Generator and Pressure Washer 10W-30

Joined
Nov 5, 2022
Messages
80
I have a generator and a pressure washer that both came with 10W-30 oil.

The pressure washer was filled with the oil that came with it and is now ready for a change. The generator has not been filled yet. I want to put the highest quality oil in it especially for the first few runs. What is the best oil to run in these small engines?
 
Joined
May 30, 2010
Messages
15,639
Location
North Carolina
I run 15w40 in my pressure washer, as it is always used in warm weather. I'm going with 0w40 in my generator going forward as it rarely gets below 0 F here.
 

HondOtaChOrd

Thread starter
Joined
Nov 5, 2022
Messages
80
The coldest it gets in my area is the upper 20's at night during winter. In summer it can get to 110.

What would you suggest running for both seasons? What is the general rule for going with a different weight than recommended by the factory?

I just bought a lot of 5W-20 synthetic blend for my car, would I be able to run that in the small engines as well?
 
Joined
Aug 20, 2003
Messages
18,951
Location
NE,Ohio
15w40 in the pressure washer
5w40 in the generator or seasonally 5w30 and 15w40(above 40f)
 
Joined
May 30, 2010
Messages
15,639
Location
North Carolina
I just bought a lot of 5W-20 synthetic blend for my car, would I be able to run that in the small engines as well?
Your car is water cooled and has temperature management via the thermostat and radiator. Your generator probably is air-cooled unless its an expensive whole house genset, and many of them are air cooled. Your pressure washer is air-cooled.

I would not run 5w20 in a generator or pressure washer, especially in summer. It will run, but it not the best choice for longevity. See above suggestions.
 
Last edited:
Joined
May 28, 2020
Messages
203
Location
MS
Read your owners manual on the generator. Your not specific but seem to say it has never been run. Generator makers usually require some form of break in. My generator manual was very specific as to what grade of oil to use and specified an oil change after 5 hours of run time.
 
Joined
Aug 11, 2011
Messages
5,553
Location
N.C.
I’ve ran Rotella T5 15w40 in my Troy Bilt 10 hp Briggs 5,500/8,500 generator for 20 years…still starts and runs like new.
 
Joined
Mar 30, 2015
Messages
9,975
Location
Lake Havasu City, Arizona
I run Valvoline 15W-50 in all of my air cooled 4-stroke power equipment. It rarely gets below 45 F out here in the Winter. (65 F in the garage where everything is kept). But in the Summer it can easily get to 118 F, and sometimes even higher. The 15W-50 is perfect for that weather, and high oil temps.
 
Joined
Feb 4, 2020
Messages
419
Location
MI
Look in the manual. I bet they specify 10W-30.

I agree with many of the posts on BITOG about pressure washers. There seems to be evidence on BITOG that a 15W-40 or some flavor of -40 oil is beneficial. Pressure washers operate full speed and high loads while in operation. Change oil early and often during break-in.

The generator can use any generic 10W-30 for break-in. Usually people change the oil early and often during break-in to flush out any manufacturing debris and also the initial metalic wear-in particles. After a few oil changes, then run whatever you want. I've run Mobil 1 10W-30 for decades, but I'm switching over to Mobil 1 5W-40 on the next oil change to allow easier starts in the winter.
 
Joined
Jul 30, 2015
Messages
1,206
Location
Pennsylvania
I have a generator and a pressure washer that both came with 10W-30 oil.

The pressure washer was filled with the oil that came with it and is now ready for a change. The generator has not been filled yet. I want to put the highest quality oil in it especially for the first few runs. What is the best oil to run in these small engines?
You didn't mention the brand of engine on either machine. Briggs and Stratton recommends anything from 5w-30 to 15w-50 for their OPE engines, depending upon the application and climate. I regularly use 10w-30 Mobil1 High Mileage in both of those applications here in southeastern PA. The pressure washer has a Honda GCV160 and the generator is a Chonda or Chinese Honda knock off. A 15w-40 wouldn't be a bad idea when running the generator continuously above 90 degrees.
 
Joined
Dec 22, 2002
Messages
4,752
Location
The Garden State
My 10 year old Briggs 5500W generator started it first six years of use using Briggs synthetic 5W-30 oil, I got a bunch for less than $5/qt. I'm now using Valvoline Synthetic MaxLife HM 10W-30. I have the "standard" Briggs crankshaft seal leak. The Valvoline MaxLife has helped minimize the leak. It doesn't get too hot or too cold where I live and the generator is kept in the garage, that's below the house and kind of climate controlled in the summer and winter. My power washer is a Troy-Bilt with a flat head Briggs engine. That's only gotten SAE30 HD oil because I only use it in the warm weather. Though I would have no problem using the Rotella T 10W-30 that I use in my snowblower.
 
Joined
Sep 30, 2013
Messages
15,252
Location
Indiana
0w40 if you aren’t concerned with running what the manual says otherwise a gas/ diesel rated 10w30 or a 5w30 A3/B4.
 
Top