# Help identifying this part on a 1998 Mercedes s420 engine.



## tireshark (Aug 17, 2014)

Neighbor has had issues starting his car for a while... thinks it might have something to do with this part. He said it is squealing like a bearing or something might be bad. There are two of them, one on either side of the engine... thanks for any help identifying what it is!


http://i.imgur.com/SEtq3u2.jpg?1


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## Windows on Wash (Aug 30, 2011)

Looks like the motor is a variable valve timing motor.

https://www.fcpeuro.com/products/mercedes-engine-camshaft-timing-adjuster-1190510077


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## Brainbucket (Mar 30, 2015)

I believe that is a 'left camshaft adjuster'. Do not let a shade tree work on that. Only a tech who has worked on Mercedes Benz should or get ready for the excuses and cost. That is an all day job for the experienced tech. That engine has 4 camshafts. 2 on each side:vs_coffee:


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## tireshark (Aug 17, 2014)

Thanks guys.

A little more info:

He has sporadically been unable to start his car over the last few weeks. Sometimes i will boost him, even though the battery appears decently charged... when boosted it will crank very strong, but never turn over. We thought it might be the alternator, but seeing how strong it cranks made us think that it might be something besides the alternator or battery.

We were thinking something like a fuel or other issue, and he seems to think it has something to do with this part, since it was making a high pitched whining noise.

Does anyone know if this part would be related to those symptoms?

Still researching it, but thanks for pointing me in a direction, and thanks for any more advice. 

Interesting what you said Braintree... he was under the impression that he might be able to just swap the new part in easily... maybe not, from what you have said. Dude is really tight on cash and has 5 kids, and this is his only vehicle... so he is trying to keep from having to take it to a shop.

Thanks again.


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## Brainbucket (Mar 30, 2015)

To a good tech, this job is hard but not bad. From reading the procedure, it doesn't seem all that hard. BUT if you haven't work on a complex engine as this one, well one mistake and a few grand later it would seem that hind sight is better. If he wants to tackle it, get the procedure and do it exactly. And get the adjuster from the dealer. Also, JMHO if you can't afford a repair with 5 kids, well get a much cheaper car that he can work on as Mercedes Benz take more to repair that most vehicles. Did you know that you can't buy a tie rod end and repair you front end? You have to buy the whole assembly from Mercedes Benz. Not this car but I just repaired one, and the tie rod assembly, whole steering linkage, for round $750.00 just for the assembly. Not including the labor and alignment. Chevy tie rod end, not the whole assembly is $28.74. So when they come into my shop and say "I'm really tight on cash and has 5 kids, and this is my only vehicle", well I look at them and then at the car. Who's living beyond their means? I will try to help but I can't do it for nothing.:vs_coffee:


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## tireshark (Aug 17, 2014)

So just to clarify, the camshaft timing adjuster could possibly be related to the engine not turning over?

Yeah he thought that you could just unscrew the adjuster and screw the new one in... but it sounds like it might be a little more detailed than that from what you are saying. He used to be a truck driver, and has a little experience doing DIY stuff, so not sure if he will tackle it or not.

The car has like 200k miles on it or something, and i think he only paid a couple grand for it a few years ago, so it isn't really a luxury thing... but at the same time, he has recently been wanting to get something else because of how expensive these things are to work on, like you were saying.

Thanks again for your input.


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## tireshark (Aug 17, 2014)

I've been talking to some other people, and they said that part (camshaft sensors magnet timing, or whatever it's called) shouldn't cause the car to not start if they are defective.

They also mentioned that it might be the crankshaft position sensor, and now that i have read up on those it sounds like it might could be a possibility.

One reason is because i have read several people talking about how replacing the cps fixed a problem where the car wouldn't start when WARM... which reminded me that yesterday the car started up fine and idled for a few minutes, then he turned it off and tried to restart it and that's when it wouldn't turn over and we couldn't boost it. So, might be the cps.


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## Windows on Wash (Aug 30, 2011)

The camshaft timing would not prevent the engine from turning over unless the camshaft timing were so messed up that it was creating an interference issue with the motor. If that is the case you've already, at minimum, ruined the cylinder head and possibly ruined the motor.

If my turning over you meant starting, then the lack of proper camshaft timing can definitely prevent the engine from starting.

You have to start with the basics though. You need to in sure that you got fuel and spark. 

Once you verify dad you can also start looking at camshaft timing.

I agree with brainbucket though that this is not a Shadetree mechanic repair.


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## Brainbucket (Mar 30, 2015)

No start is when the engine is cranking (turning over) but will not start/run. No crank means the engine will not crank (turn over). If it will not crank, then starter or pulley on the drive belt? If it won't crank, pull the drive belt then try it. If it cranks then turn off engine and reach down and turn all the pulley in the drive belt area. One that's locked up will stop it from cranking. If it will crank but not start then most likely the check engine light is on. It's a 98 model so it has OBDll. Look at the codes and tell us what they are.:vs_coffee:


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## tireshark (Aug 17, 2014)

My mistake, i now realize that 'cranking' and 'turning over' mean the same thing. Yes i meant that it would crank, but it wouldn't start. Yeah i will tell him we should check fuel/spark also.

I've read a lot of people saying that a bad crankshaft position sensor will cause it to not start, and it seems like a pretty easy repair job plus it's only $25-50 depending on the quality of the part. Actually they have them on ebay for $9... if you wanted to get real cheap with it.

Thanks


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## Brainbucket (Mar 30, 2015)

Please don't throw parts at it. You are wasting money. I get that all the time. "I put this and this and that on there and I've spent $(who knows how much) on this car and I don't have any more money to put in this car!" Then I check it and it's usually 1/4 to 1/2 the amount they put in it guessing. If it is the crank sensor then a code is in the ECM and the check engine light is most likely on. Read the codes first. When cranking, the tach usually will move a few hundred RPM's if the crank sensor is working.:vs_coffee:


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## ukrkoz (Dec 31, 2010)

Read what the "other people" - me - said at the other place. It's part of ignition system and apparently high voltage producing one. What might that be then on 87 car?


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## Brainbucket (Mar 30, 2015)

ukrkoz said:


> Read what the "other people" - me - said at the other place. It's part of ignition system and apparently high voltage producing one. What might that be then on 87 car?


An 87 what?:vs_worry:


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## tireshark (Aug 17, 2014)

ukrkoz said:


> Read what the "other people" - me - said at the other place. It's part of ignition system and apparently high voltage producing one. What might that be then on 87 car?


When i said 'other people' i wasn't referring to you, or the other site.

The part i initially asked about, that you are talking about, is the valve cover.

Dont know where you are getting 87, it is a 98.


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