# 80W-90 Non-Detergent Oil for Pressure Washer



## m_ridzon (Sep 29, 2017)

My pressure washer manual says to fill the crankcase with 80W-90 *non-detergent *oil. I am having a hard time finding this. A Google search produces 80W-90 gear oil, but I don't see any that specifically says *non-detergent*. I studied my bottle of Chevron 80W-90 oil in the shop and also called the local Chevron supplier who wasn't very helpful. There are no notations about the use of detergent or not. The Chevron supplier said he's never heard "detergent" and "gear oil" in the same sentence; rather, usually only in engine oil discussions.

I know the different between detergent and non-detergent. I realize engines from decades ago had no oil filters, but the eventual transition to incorporate filters into the engine design, brought on the advent of detergent engine oil. Since 80W-90 is typically used in closed gear cases without filters, and without combustion byproducts that exists in engines, I wonder if all 80W-90 oil is non-detergent by default. Can any oil experts chime in to share feedback?


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## mark sr (Jun 13, 2017)

Double check your manual as that doesn't sound right. I run detergent oil in my PWer's crankcase. I think the pump uses hydraulic fluid.


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## Old Thomas (Nov 28, 2019)

The crankcase of the engine? I never heard of an engine using that oil. I would check with the engine manufacturer, if the manual says to put that in the crankcase I would suspect a misprint and I would confirm it before filling it.


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## m_ridzon (Sep 29, 2017)

mark sr said:


> Double check your manual as that doesn't sound right. I run detergent oil in my PWer's crankcase. I think the pump uses hydraulic fluid.


No question about it. The manual says to use non-detergent in the water pump's gear case.


Old Thomas said:


> The crankcase of the engine? I never heard of an engine using that oil. I would check with the engine manufacturer, if the manual says to put that in the crankcase I would suspect a misprint and I would confirm it before filling it.


Sorry, no it is not the crankcase of the engine. (it doesn't have an engine; rather, it's power by an electric motor). It's the water pump's gear case that requires 80W-90 non-detergent oil.


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## Randy Bush (Dec 9, 2020)

A misprint 80-90 w is not made to run in a engine. Are you sure it is not talking about the oil for the washer pump, seems some use a oil.


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## Randy Bush (Dec 9, 2020)

m_ridzon said:


> No question about it. The manual says to use non-detergent in the water pump's gear case.
> Sorry, no it is not the crankcase of the engine. (it doesn't have an engine; rather, it's power by an electric motor). It's the water pump's gear case that requires 80W-90 non-detergent oil.


In that case any parts store will have 80-90 w gear lube.


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## m_ridzon (Sep 29, 2017)

I've attached an electronic PDF of the owner's manual. Page 11 of the manual (bullet number 12), specifically says to use *non-detergent *oil for the water pump's gear case.


Randy Bush said:


> In that case any parts store will have 80-90 w gear lube.


Yes, I agree. But the question is "is ordinary gear oil *non-detergent*?" I cannot find anything in the parts store, or the internet that specifically denotes 80W-90 gear oil as "non-detergent." Oil manufacturer's do not seem to mention this in their product specifications for gear oil.


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## Old Thomas (Nov 28, 2019)

Detergent oil keeps crap in suspension so the filter can strain it out. Gear boxes benefit from crap settling out and not being held in suspension. I have no proof but it makes sense to me that gear oil would not have detergent. I would fill it with regular gear oil.


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## m_ridzon (Sep 29, 2017)

Old Thomas said:


> Detergent oil keeps crap in suspension so the filter can strain it out. Gear boxes benefit from crap settling out and not being held in suspension. I have no proof but it makes sense to me that gear oil would not have detergent. I would fill it with regular gear oil.


This was my sentiments too. It seems logical that gear oil would NOT have detergent.


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## huesmann (Aug 18, 2011)

You probably also want to avoid gear oils with limited slip additive.


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## bob22 (May 28, 2008)

Amazon has this:
https://www.amazon.com/Briggs-Strat...ressure+Washer+Pump+Oil&qid=1608055395&sr=8-5


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## m_ridzon (Sep 29, 2017)

Well, case closed, I think. I drove to the nearby pressure washer repair shop to ask them. I showed them my pump. They said they put 30W non-detergent in ALL of their rebuilds. I recoiled a little bit and asked if the lighter weight was okay. They assured me it was fine and they've been doing it that way for several decades. They then sold me a pint of pump oil for $5 (spec sheet HERE). What they sold me is actually 50W (not 30w) according to HERE. But that certainly won't hurt. So I think I'll run with it and close this chapter.


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