Help with pump oil

Okay ladies and gents. I am in desperate need of somewhere to buy some oil for my pump. I’ve have searched high, and I have looked low and found nothing that my pump calls for. It’s a legacy 3500 psi 4.8 gpm. On the pump it says “use legacy pump oil# 8.901-0.770 non foaming” I have entered every combination of the sentence and only thing that comes up is sae30. Now I already have a bottle of that stuff and it’s looking like I’m going to have to use it temporarily till I find the oil my pump calls for. Can someone please post a link if they have one? Appreciate it greatly…

I run 30w non-detergent in my udor pump. I think a lot of people on here do


Part # ND30-QT


Call the manufacturer but pumps use nondetergent oil. My hardware store sells two brands of it and one looks like water got into my pump after it runs for 2 days.

I use 30w non-detergent that any parts store will carry.


Ditto. Guy at Autozone had to dig around in the back to find some.

Yeah, I’m able to easily find 30, but my pump calls specifically for 20w/40. See the picture

I can’t find any info on manufacturer


I appreciate you posting the link like I asked, but the oil is for my pressure washer pump. It need to be non foaming or non detergent.

Yeah sorry I missed that. Long day. I’ve started really digging out of curiosity and I’m not finding any.

Yeah no worries thanks for the attempt though. But now you see what I’m going through lol

A 30 weight oil will be fine. You’re not talking about much of a difference. The 40 weight is just a tiny bit thicker. That pump isn’t designed any different than any other pump so I wouldn’t worry about it at all. You could even use the 40 weight that isn’t non detergent. Not really going to hurt anything either. You might just get some foaming of the oil when running. I’d going with the non detergent 30 weight though.


Alright thank you. My system only has about 40 hours on it. I bought it with much less than that, but I go to check the oil the other day and the level was too low to hit the dipstick. It had been sitting unused for about 2 years before I purchased it so I’m not to sure what happend to it all. Thank you for your response. I appreciate it

I would completely drain the old oil before adding new. Mixing different weights of oil won’t hurt anything but you might as well start fresh. 40 hours is nothing on a machine so it should last you a long time if you take care of it. Get in the habit of checking oil levels every morning before starting it for the day. Low oil is the number one killer of an small engine. It usually overheats and ends up throwing a rod.

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Oh okay, so is my dissapeared oil a common thing and not to be worried about or investigated?

Don’t worry about now because you don’t know the history. Just drain and refill and keep an eye on it. And as everyone said, the 30w nd is fine. They sell pump oil at Northern Tool also if you have one close.

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Only northern tool around me is their webpage on my phone Haha. The pump (as well as engine and heater) had around 9 or 10 hours on it when I got so now much history, I was thinking a seal went bad from just sitting for so long and leaked out but idk. Anyway I’ll go ahead and try the 30. Thank you sir and thank you to everyone who chimed in, I appreciate it