# 10w30-10w40 motor oil



## JustinRaney (Jun 1, 2018)

I have a 2007 g6 with a 182k miles. It calls for 5w30 but i usually use 10w30. As it leaks a quart every 1000-1500 miles from a small valve cover leak. Is it okay to switch to a thicker oil 10w40 to help prevent any leaking or is it best to use the 10w30 for bearing clearances.

Ive used synthetic blend 10w30 supertech 5k mile oil last year but walmart doesnt stock the supertech synthetic blend 5k mile oil anymore. So i purchased quaker state conventional 10w30 this time around the problem is conventional is a 3k mile oil and synthetic blend is a 5k mile oil.
Just curious if i should just go with what i got the 18$ quaker state conventional 3k mile oil 10w30 or switch to a 10w40 or a synthetic blend which says 5k miles which i think is for any synthetic blend oil.
The thing is you get 2k extra miles on the synthetic blend which is worth the extra 5$ and not having to change the oil as often.

I was using walmarts supertech 13$ conventional 5 quart oils before but had to switch to there 16$ synthetic blend last year 5k mile but found out this year they dont stock the synthetic blend supertech anymore and on the website says not available at any store so that left me with 18$ quaker state conventional. It appears that quaker state conventional 16$ oil isnt available anymore on walmarts shelf so the all mileage is what ill have to use.

Heres direct links The first is the cheapest available option the last 2 arent available anymore at both local walmarts. Is it worth it to get a synthetic blend which should be expected to last 5k miles as per walmarts supertech 5k mile synthetic blend advertisement.
Quaker State All Mileage 10W-30 Motor Oil, 5 Quart - Walmart.com 











Super Tech All Mileage Synthetic Blend Motor Oil SAE 10W-30, 5 Quarts - Walmart.com 









Quaker State Motor Oil, Conventional 10W-30, 5-Quart - Walmart.com


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## chandler48 (Jun 5, 2017)

Why don't you do it right, replace the valve cover gasket and go back to the specified oil? Seems like a logical way of doing it.


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## JustinRaney (Jun 1, 2018)

There is the valvoline high mileage synthetic blend for 23$ would this be better to use and run it to 5k mile oil changes. I cant say how long synthetic blend is to be changed as im assuming 5k miles just as walmarts old synthetic blend jug advertisements. My 99 corvette according to the manual is 7500 miles on full synthetic.
Valvoline High Mileage MaxLife 10W-30 Synthetic Blend Motor Oil 5 QT - Walmart.com


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## JustinRaney (Jun 1, 2018)

Oh no i was simply referring to running different weight oil as well as conventional to synthetic blend. On my 66 fairlane with a 351 cleveland i think i may have ran 10w30 in the winter and 10w40 in the hot texas summers when i was 17 in 2007. I think quaker state conventional oil was around 2.20$ at that time in 2007 a quart.

The question was more about how walmart doesnt stock its 13$ conventional supertech anymore and just this year stopped having there 16$ supertech synthetic blend 5k mile oil so i was forced to the next cheaper option quaker state all mileage conventional for 18$. I still havent done the oil change so i can return the 3k mile oil and swap to a 23$ valvoline synthetic blend if all are 5k mile oil changes that leaves me 2k extra miles without having to change the oil. Its for my younger brothers daily driver 2007 g6 he uses for work. I have a 99 corvette no oil leaks that i run quaker state full synthetic in but on an economy cruiser i dont see a point in running race oil. See my above post about the other option valvoline synthetic blend for 23$ if all synthetic blends are 5k mile oils and not 3k mile as conventional saves me time then doing the oil change sooner.


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## MIShopDude (9 mo ago)

The difference between 10-30 and 10-40 is almost nothing until the weather gets really cold or really hot. 

Sometimes I think the engine manufactures decided which oil they recommend by throwing a dart at a wall with little pictures of different grade oils. 

Synthetic oil is far superior to conventional oil in every way.


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## Randy Bush (Dec 9, 2020)

The 3k on conventional oil is a myth. Pretty much all newer cars can go much longer depending on the type of driving you do. My 2000 buick with 260k on it and my 2009 buick I go by the revolution counter of the computer to change the oil. Never have had a problem. Older carb engines yes to 3k ,but not newer ones.


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## chandler48 (Jun 5, 2017)

But using a thicker oil or even an oil additive to thwart the inevitable repair needed to stop the leak where the prescribed oil can be used is ludicrous. Fix the car and use the right oil.

That WAS your original question: "Is it okay to switch to a thicker oil 10w40 to help prevent any leaking "


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## Randy Bush (Dec 9, 2020)

I had a guy that dealt in oil a lot tell me that most all engine oil anymore is synthetic to some degree because of the way it is made.


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## Msradell (Sep 1, 2011)

MIShopDude said:


> The difference between 10-30 and 10-40 is almost nothing until the weather gets really cold or really hot.
> 
> Synthetic oil is far superior to conventional oil in every way.


10W-30 and 10W-40 will behave exactly the same when the weather is cold (that's what the 10 indicates) and will only very slightly at high temperatures.

You may have done yourself a slight disservice by using 10W-30 instead of the recommended 5W-30. Newer engines are made to tighter tolerances and the 5W-30 it slightly thinner at startup so provide better lubrication immediately when you start the engine.


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## FM3 (Aug 12, 2019)

Justwayne said:


> Is it okay to switch to a thicker oil 10w40 to help prevent any leaking or is it best to use the 10w30 for bearing clearances.


What does the car's manual say to use? Use that. Unless it's something ridiculous like 0w16. Then I'd think twice.

Even modern conventional oil is much better than oil from decades ago. 3k used to be a thing but now isn't. And, yes, some/many/all(?) "conventional" oil now is a form of synth blend. I've seen a couple people quite upset about that for whatever particular use they wanted full conventional for -- the oil maker changed the formula but didn't put "synth blend" anywhere on the bottle.

If no one wants to change the valve cover for some reason, the best hope you'll have of helping the leak is using the high-mileage oils. They really can work.


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## JustinRaney (Jun 1, 2018)

Oh not necessarily i may have messed up mentioning the leaking part i merely meant switching to a thicker oil from 5w30 or 10w30 to 10w40 for whatever reason higher mileage and such maybe thicker oil. Its almost at 182k so if i use the 4 quarts of the 5 quart jug of conventional quaker state 10w30 i have itll be good to 185k miles.
My brothers 06 saab 9-5 2.3 turbo i like to use full synthetic as the oil flows thru turbo adding heat to the oil i assume.
My 98 z28 ls1 when i was 19-23 in 09-12 i used valvoline full synthetic not sure if 10w30 or 10w40 was along time ago autozone oil and filter special with cam headers 375whp 375 wtq and 501whp 465wtq 6lbs turbo s475 and 9lbs maybe 550whp/500wtq till 169k miles when it threw the stock shortblock wristpin thru the side of the block boosting 9lbs in 4th at the end of the track SAR here in san antonio late 2012 when i was 23 im 33 now.

I had read an article about an ls1 engine and running different oil weights months ago. They had a 300k mile + ls1 engine and ran the same 5w30 for bearing clearance purposes and recommended the same oil versus switching to a thicker oil. Thicker oil would cause more wear on the oil pump or stress the bearings with tighter clearances not sure what all the article contained or how to go about getting 300k+ miles.
That was some of my concern when switching from 30w to 40w.
What are you saying conventional oil is good for mile wise when used on a car thats shifts around 2-3k on an auto?


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## JustinRaney (Jun 1, 2018)

Msradell said:


> 10W-30 and 10W-40 will behave exactly the same when the weather is cold (that's what the 10 indicates) and will only very slightly at high temperatures.
> 
> You may have done yourself a slight disservice by using 10W-30 instead of the recommended 5W-30. Newer engines are made to tighter tolerances and the 5W-30 it slightly thinner at startup so provide better lubrication immediately when you start the engine.


Are you saying to use 5w30 instead of the 10w30? Yes all 3 cars the 07 g6 06 saab 9-5 and my 99 corvette say 5w30. On the saab with 156k miles i used 5w30 full synthetic for specific expensive saab reasons and 5w30 on my 94k mile corvette for expensive specific corvette reasons.

Youre saying to use 5w30 on the 07 g6 i would have to confirm the oil cap says that vs the 10w30 thats on the shelf? Its possibly 5w30 not be available but i would have to check walmarts stock on their website. This is texas weather its about to get into the 60s-50s-40s-30 degrees in dec to feb this winter.
Its not a problem adding a little oil here and there my main concern was as i was grabbing 10w30 someone else at walmart was grabbing 10w40 made me think maybe the 10w40 was a better oil. Could be an older 80 90s vehicle for all i know.


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## FM3 (Aug 12, 2019)

Justwayne said:


> What are you saying conventional oil is good for mile wise when used on a car thats shifts around 2-3k on an auto?


When in doubt, change it at 5k unless there is an obvious reason to change it earlier such as lots of blow-by making the oil look bad prematurely. It could probably be changed later than 5k, but probably a max of 7,500 miles, and cleaner oil is always better than dirty oil, so 5k is a good rule of thumb that makes most people feel good. 

Can change it less of course if the car is losing a good bit of oil from a leak since new oil has to be added before oil change time anyway.

For the couple dollars difference, I'd certainly use a labeled synth blend than labeled conventional. Locally, I usually can get synth blend for cheaper than conventional for whatever reason. And I've seen enough synth blend oil wear tests to not worry about needing full synth unless it's for atypical use.


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## peter1122 (8 mo ago)

there is never any reason to deviate from what the manufacturer recommends,

your oil pump is designed to pump the viscosity of the recommended oil,

when it has to pump a thicker oil, it put more strain on it,

also, a thicker oil is not going to leak any less, or any more

i used to work at a shop, when a customer asked me "what grade of oil should i use?"

i used to answer "what does it say on your oil cap?"


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## 660catman (Aug 25, 2019)

Justwayne said:


> Are you saying to use 5w30 instead of the 10w30? Yes all 3 cars the 07 g6 06 saab 9-5 and my 99 corvette say 5w30. On the saab with 156k miles i used 5w30 full synthetic for specific expensive saab reasons and 5w30 on my 94k mile corvette for expensive specific corvette reasons.
> 
> Youre saying to use 5w30 on the 07 g6 i would have to confirm the oil cap says that vs the 10w30 thats on the shelf? Its possibly 5w30 not be available but i would have to check walmarts stock on their website. This is texas weather its about to get into the 60s-50s-40s-30 degrees in dec to feb this winter.
> Its not a problem adding a little oil here and there my main concern was as i was grabbing 10w30 someone else at walmart was grabbing 10w40 made me think maybe the 10w40 was a better oil. Could be an older 80 90s vehicle for all i know.


As said already, use what is recommended for your vehicle. I’m in Canada where temps get to -30 to -40 below and I used full synthetic 5w-30 in my 2013 Silverado gas. I now have a Duramax diesel and use 15w-40 year round but that’s also full synthetic. I use nothing but full synthetic. 


Retired guy from Southern Manitoba, Canada.


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## JustinRaney (Jun 1, 2018)

660catman said:


> As said already, use what is recommended for your vehicle. I’m in Canada where temps get to -30 to -40 below and I used full synthetic 5w-30 in my 2013 Silverado gas. I now have a Duramax diesel and use 15w-40 year round but that’s also full synthetic. I use nothing but full synthetic.
> 
> 
> Retired guy from Southern Manitoba, Canada.


Yes my father was just telling me the 5w was for colder temperatures. I live in texas where it doesnt get below 30 degrees rarely in the winter between dec-feb. He also stated that wouldnt the added extra oil weight say 10w30 vs 5w stay on the engine parts longer. The cars daily driven. I think the 5w is for colder temperatures such as 0 degrees. Ive been using 10w30 the last 25k miles just on the saab 06 9-5 2.3 turbo i used full synthetic 5w30. Walmarts supertech filters are the cheapest and say 10k miles on them. I really am trying to keep the car running and get the most miles out of it i just read over on the g6 forum a guys at 266k miles. My grandparents owned the 2007 G6 since 2008 when it was a year old car and id like to keep it running.

Maybe ill see if the valvoline high mileage synthetic blend 5w30 is available. Ive used quaker state conventional in my classic 66 fairlane when i was 17 in 2007 for high school and never had problems with it. Quaker state conventional is the cheapest option at walmart for 18$

Debating whether i should return the 10w30 for a 5w30 jug from the local walmart 5 minutes up the road.

I also use full synthetic on my 99 corvette with cam headers.The recommended oil change is 7500 miles. Now with that being said the walmart jug says 5k or 10k miles full synthetic or after a year to do an oil change. I used quaker state full synthetic oil last march after doing the cam swap.

According to walmarts supertech do i need to change the oil yearly or at the mileage. Its my daily driver i bought it at 91k 16 months ago changed the oil at 93k miles its at 94k miles now. I doubt that ill get to 7500 miles before next march-april so i need to change that yearly according to walmarts supertech jug but as i used quaker state full synthetic which doesnt say what mileage or year whichever comes first.

Would anyone happen to know if you do have to change oil yearly or at the certain mileage as i hate to waste oil if i only put 3-4k miles on the car within the year a 7500 mile full synthetic.


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## JustinRaney (Jun 1, 2018)

Now about this thicker oil debate say 30w-40w im sure bearings do show a little wear above 150k miles or atleast normally you can see the first layer worn off this wouldnt possibly require the use of possibly a slightly thicker oil or are you referring to smaller oil orifices and oil paths requiring the 5w vs 10w.


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## JustinRaney (Jun 1, 2018)

Yeah i see i may have mentioned it wrong i was simply referring to 182k mile car and possibly 10w40 vs 10w30 for possible bearing wear and such. Hot temperatures in texas summer 107 degrees and coldest it gets in winter is 30 degrees.


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## JustinRaney (Jun 1, 2018)

Now this is terrible autozone has the same oil for 26$ vs walmarts 17.97 quaker state all mileage. Autozone has this all mileage quaker state listed as a synthetic blend is this a misreading or false advertisement or is this oil a synthetic blend that can be run up to 5k miles vs the standard 3k mile conventional oil.
Guess walmart is cheaper by 8$ for the 5 quart jug and possibly a synthetic blend which is usually run up to 5k miles.

Quaker State All Mileage Engine Oil Synthetic Blend 5W-30 5 Quart (autozone.com)










Quaker State 5W-30 All Mileage Motor Oil, 5 Quart - Walmart.com


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## Oso954 (Jun 23, 2012)

There is a difference between a synthetic oil (100% synthetic) and a synthetic blend (A mix between synthetic and mineral oil).

Autozone has it right, the Quaker State All Mileage oil is a synthetic blend.


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## JustinRaney (Jun 1, 2018)

Hey yes im aware of full synthetic, synthetic blend differences and just what is called conventional oil. Thanks for the confirmation.


So its safe to assume this qauker state all mileage is a nice synthetic blend that can be run up to 5k miles? Or is can it be run higher mileage 6-7k? I may just return or swap this 10w30 ive been using for the 5w30 to walmart though ive been using 10w30 the last 30k miles on the car because of the texas heat. Only thing that caught my eye is i was changing the 06 saab 9-5 turbo oil and seen it was 5w30 so went specifically with a full synthetic 5w30 supertech 10k mile oil last year when i was changing the oil on that car as the oil is also run thru the turbo oil feed/drain extra added heat protection from full synthetic. Really am trying to make sure to get the most mileage out of these engines as i was disfigured in a car wreck in 2017 age 27 after someone had rear ended my 2001 ford escort so im somewhat disabled why i prefer doing less oil changes and get the expected mileage out of the oil its a real pain for me. Im somewhat mechanically inclined at age 17 but after having been disabled from that car wreck left me paralyzed a bunch of slipped disc and permanent spine ribcage pain.


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## SeniorSitizen (Sep 10, 2012)

Oil viscosity will never solve the oil leaking problem on a 15 year old engine so replace cover gasket then determine if the crankcase vacuum is correct .


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## lenaitch (Feb 10, 2014)

I have a hard time following the OP's posts - too much irrelevant data and irrelevant other vehicles. I don't really have a position on conventional vs. synthetic oil; I've always used conventional in my vehicles (except my newer Honda which calls for 0wxx) and changed it and the filter per the book if not sooner.

If the goal is keep an old blister running as long as possible, don't make your decision based on price. At best you are saving a handful of dollars per change.


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## chandler48 (Jun 5, 2017)

Justwayne said:


> Debating whether i should return the 10w30 for a 5w30 jug from the local walmart 5 minutes up the road.


Debate??? With whom?

Change your oil when you can't read through it on the dipstick.



Justwayne said:


> Now about this thicker oil debate


Again, there's no debate on thicker oil. Use the oil called for by the manufacturer and fix your leak. Bearings wear. Oil won't help it.


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## JustinRaney (Jun 1, 2018)

Ah here it says my g6 owners manual use 5w30 or 0w30 if -20f degrees. Do not use thicker oils 20w50. Doesnt mention anything about 10w30 or 10w40.

Here on ls1 v8 says 5w30 above 0 10w30 can be used for 99 corvette or camaro ls1 5.7 im hoping when i did the last oil change i did use 10w30 full synthetic quakerstate after the cam swap last march. Im pretty sure i didnt select 10w40 as the car has 94k miles pretty low mileage. I think i did go with 10w30 vs the oil caps 5w30 but it never gets below 0 here in texas coldest is 20f degrees in the winter rarely.

SAE30 can be used. I still think itd be fine to run the 10w30 opposed to the 5w30. 5w30 or 0w30 is in reference to -20-0f 10w30 is recommended around 40f or above.

just make sure not to sae50 or 20w50 it.

The thinner oil less friction more power.


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## chandler48 (Jun 5, 2017)

Justwayne said:


> Do not use thicker oils 20w50. Doesnt mention anything about 10w30 or 10w40.


That's about the (I can't think of a word) comment of the day. It says "Do not use thicker oil" Gee, what do you need?



Justwayne said:


> SAE30 can be used


No it can't. SAE 30 is a non detergent oil and will kill your engine.


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## JustinRaney (Jun 1, 2018)

I still think in 80 degree heat 10w30 would work fine lol.


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## JustinRaney (Jun 1, 2018)

chandler48 said:


> That's about the (I can't think of a word) comment of the day. It says "Do not use thicker oil" Gee, what do you need?
> 
> 
> No it can't. SAE 30 is a non detergent oil and will kill your engine.


It says here if it falls below -20f 5w30 or 0w30sae can be used is 0w30 not simply sae30?


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## chandler48 (Jun 5, 2017)

WIth all the good advice given to you on this matter, and you still want to do the wrong thing, I think you should run the 10W30 in everything until they won't run any longer. You will have gotten all the money's worth from the cars and you can scrap them for $10 each. You already have your mind set on doing it anyway, so don't listen to good advice.

You have absolutely zero knowledge of the oil matter, but are hell bent on doing it. No you can't use SAE 30 except in a lawn mower. 



Justwayne said:


> if it falls below -20f


 If, If , If....if frogs had wings, they wouldn't bump their butts when they landed.


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## JustinRaney (Jun 1, 2018)

Man here is my proof is 0w30 not SAE30? I may be mistaken not sure what sae means straight 30 weight no with a 0?
5w30 or 0w30 0 degrees or below. 5w30 for 0 and above this is the g6 manual not the 20w50 or higher viscocitys.

Use only 5w30 synthetic oil below 0-20 degrees or 0w30 for extra added lubrication. May i ask is there a 0w30 or is sae30 which i always thought meant straight 30weight meant simply 30weight oil.

Is the sae 30 or sae50 simply a 30w30 and 50w50 on cold starts?
Read the second paragraph about 0w30. 0w30 means theres nothing if you ask me for the first start as in 0 viscosity? Depends i dont know specific oil grade scales when it comes to 0 viscosity.


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## JustinRaney (Jun 1, 2018)

I was using 10w30 the last 20k miles its 107 degrees here in summer texas heat. Im going to return the quaker state 10w30 in favor for a 5w30 i hope they have one on the shelf. A guy over on the g6 forum has 266k miles on his 06 g6 v6 3.5l im hoping to get the same mileage. The 2007 g6 isnt driven hard its my younger brothers daily driver for work i just do that mechanics to it. That little article from the owners manual in the glove box should give all the information needed.

I probably do need to figure out how to do a transmission fluid change on this car as its at 182k. Im hoping there a bolt drain plug would be nice to change the auto trans filter to get the most life out of the transmission.


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## JustinRaney (Jun 1, 2018)

chandler48 said:


> WIth all the good advice given to you on this matter, and you still want to do the wrong thing, I think you should run the 10W30 in everything until they won't run any longer. You will have gotten all the money's worth from the cars and you can scrap them for $10 each. You already have your mind set on doing it anyway, so don't listen to good advice.
> 
> You have absolutely zero knowledge of the oil matter, but are hell bent on doing it. No you can't use SAE 30 except in a lawn mower.
> 
> ...


Im pretty smart dont drop your finger dude i seen jeepers creepers 3 sucked and an axe ended up in his head.

Ive been tied up in a big audit for the last 10 years from late 2012 i havent been around to see these new spaceship type of vehicles? May i ask are you military or receive military contact?

Yes im going by what the owners manuals i have here go by need to return this 10w30 for a 5w30. Not sure why it says full synthetic 5w30 or 0w30 below 0 degrees- -20f.
Read the paragraph in the photos from the manual i uploaded.
This was a good conversation the owners manual wins the debate or solves the question. Dont mess up my ride dude.


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## JustinRaney (Jun 1, 2018)

Im all for a good oil discussion but youre tearing into a lawnmower at this point.


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## notnew2diy (Sep 1, 2017)

A simple google of... What does SAE stand for? 
Answer... _Society of Automotive Engineers_ 

SAE30 = straight 30 weight oil.
xxWyy oil = detergent oil. It also has additives to reduce friction at start up in cold weather (the xx). 

Older engines leak. I, personally, would not use synthetic in a used engine unless it had synthetic from day-1.

Back in the day, dunno if it still applies, Pennzoil had a wax substance within the refined oil. 

I always use mfg recommendation on what weight oil to use cuz they have spent tons-o-dollars on research.

FWIW.... I knew a lady who drove a Cadillac close to 100K miles. Wondered why her car would not start one very cold day. Come to find, she had never changed the oil....believe it or not.

It's your toy. Play with it how you want....Don.


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## peter1122 (8 mo ago)

Justwayne said:


> I still think in 80 degree heat 10w30 would work fine lol.


if you think you are smarter than the engineers who designed the engine, then use whatever you want


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## JustinRaney (Jun 1, 2018)

Yeah i bet i use to use the 10w30 10w40 quaker state in my 66 fairlane 351cleveland 4v 9" with 4.10s 4 speed toploader when i was 17 in high school class of 2007.
I since bought a 95 z28 6 speed at 18 not sure what oil i used there but purchased a 98 z28 hardtop 6 speed with 119k miles for 3800$ with ttl from a small car lot. Its was in great condition bone stock. I used autozones valvoline i believe full synthetic 10w30 which is recommended for 0-40f above in the ls1 5.7 manual. Made 375whp 375wtq smaller cam then the corvette, headers and ud pulley. I later thru a s475 borg warner 1.32 ar turbo on it made 501whp 465wtq at 6lbs and possibly 550whp 500wtq 9lbs. Ran 126mph-131mph 128-129mph in 30-40 degrees midnite weather at san antonio raceway. Didnt use slicks or drag radials so the 60fts were slow 2.2. That was from 2009-2013 when i was 19-23. Im 33 now and suffered severe body damage from the idiot that ran into the back of my 2001 escort daily driver.


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## JustinRaney (Jun 1, 2018)

peter1122 said:


> if you think you are smarter than the engineers who designed the engine, then use whatever you want


Its hard to say thats what recalls are for. Some things could be designed better.


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## chandler48 (Jun 5, 2017)

notnew2diy said:


> Older engines leak. I, personally, would not use synthetic in a used engine unless it had synthetic from day-1.


I had toyed with the idea on my 2001 Cummins, but at 561,000 miles, and it ain't broke, don't fix it.


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## JustinRaney (Jun 1, 2018)

notnew2diy said:


> A simple google of... What does SAE stand for?
> Answer... _Society of Automotive Engineers_
> 
> SAE30 = straight 30 weight oil.
> ...


My father thinks synthetic is bad as well as thinner oil leaks. I personally use and always used full synthetic in my cars except for my 66 at 17 i used conventional quaker state.

Yes ive heard of the same issues or similar certain oils were bad. Are you saying this wax substance pennzoil had was a bad deal? Ive always used and trusted valvoline or mobile 1. Now for the not hard driven daily driver i think conventional or synthetic blend is fine.

The 2007 g6 and 06 saab 9-5 turbo are both my younger brothers and fathers. I just do the oil changes on them.


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## JustinRaney (Jun 1, 2018)

well swapped the 10w30 for the 5w30 problem solved 5 minute trip up to walmart.


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## FM3 (Aug 12, 2019)

Justwayne said:


> Yes im going by what the owners manuals i have here go by need to return this 10w30 for a 5w30. Not sure why it says full synthetic 5w30 or 0w30 below 0 degrees- -20f.


It says that because it's recommending in really cold weather to use full synth 5w or 0w instead of conventional or blend or a higher w. 

Lawn mower manuals say similar things. Not sure why anyone would be using a lawn mower at -20f, though I have cut the lawn when it was snowing.

As mentioned, lawn mower engines can usually use straight 30. Though I would avoid putting that in a mower, and certainly wouldn't put it in a car.

You asked about oil age. Age of oil basically doesn't matter. There's no reason to "change it at least once a year." I guess I can see it maybe being decent advice for people who drive short distances which then potentially accumulates water in the oil. 

I laughed when you said you should look into changing the transmission fluid because I was going to reply to an earlier post about the car's high mileage and say I'd be more concerned about when the trans fluid has been changed last than about minor oil quibbles.


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## notnew2diy (Sep 1, 2017)

chandler48 said:


> I had toyed with the idea on my 2001 Cummins, but at 561,000 miles, and it ain't broke, don't fix it.


I bought a new pickup in 07. Dealer supplied 2 oil changes. I used Mobil-1 there after. Decided I'd use Mobil-1 in the wife's 1999 Isuzu. It leaked. Went back to conventional, no leaks. Around the same time, decided I'd try Mobil-1 in my 1996 Craftsman riding mower. Was surprised it did not leak. Maybe it was me, seemed like it ran a bit better. I also use Mobil-1, 10w30, in my 2 stage air compressor. Supposed to run 30w, but I use the machine in winter. Knock wood... no issues.

FWIW...Don.


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## Old Thomas (Nov 28, 2019)

I would fix the oil leak and use what the owner’s manual says for oil.


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## HotRodx10 (Aug 24, 2017)

For anyone still confused, 5w-30 is a multi-viscosity oil, that means it flows more easily, as a 5 weight oil, when it's cold, but doesn't get thinner than a 30 weight oil when it gets warm. Same deal for a 0w-30 oil - flows like a zero weight oil when it's cold; maintains the viscosity of a 30 weight oil when it gets warm. SAE30 is a single weight oil - it flows like a 30 weight oil when it's cold (which is to say, not very well) and when it's warm.


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## JustinRaney (Jun 1, 2018)

Ah i see thanks for clearing up the SAE30 straight 30-30 and 0w30 differences.


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## lenaitch (Feb 10, 2014)

Forty five posts to solve what a simple Internet query would have revealed. Entertaining, though.


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## SeniorSitizen (Sep 10, 2012)

Justwayne said:


> Im all for a good oil discussion but youre tearing into a lawnmower at this point.


Your oil problems solved at the end of this STP history lesson . 






The history of STP® | STP®


For over 60 years, STP® has been one of the most trusted names in automotive care. Find out more about STP® history here.




www.stp.com


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## Matt1963 (5 mo ago)

Msradell said:


> 10W-30 and 10W-40 will behave exactly the same when the weather is cold (that's what the 10 indicates) and will only very slightly at high temperatures.
> 
> You may have done yourself a slight disservice by using 10W-30 instead of the recommended 5W-30. Newer engines are made to tighter tolerances and the 5W-30 it slightly thinner at startup so provide better lubrication immediately when you start the engine.


I agree and most people don't understand that multi grade oils get thicker after heating so the 10-40 oil will probably cause the valve cover gasket to leak more.


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## JustinRaney (Jun 1, 2018)

Any idea at what point or temperature the 5w30 or 10w40 turns from 5-10w to the 30-40weight?


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## chandler48 (Jun 5, 2017)

Justwayne said:


> Any idea at what point or temperature the 5w30 or 10w40 turns from 5-10w to the 30-40weight?


It doesn't "turn" into anything. What difference does it make? Use the right oil, repair the leak and live long and prosper.


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## JustinRaney (Jun 1, 2018)

lol im asking at what point does the 5w30 go from a cold start 5w to the hot 30w?


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## chandler48 (Jun 5, 2017)

WHen it gets hot. Again, why are you jousting at windmills. The engineers have you covered.


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## SeniorSitizen (Sep 10, 2012)

Justwayne said:


> lol im asking at what point does the 5w30 go from a cold start 5w to the hot 30w?


Most anything you would want to know is on this link .



oil viscosity vs temperature chart - Google Search


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