20w-50 over kill?

[Chris142]

The power company is working on poles in my area. They have been turning the power off as needed. Was off 9 hrs Tuesday!

I plugged the swamp coolers and refrigerator into my 4k harbor freight generator. After the power came back on I changed the oil in the generator so that it's ready to go for the next time.

I had some Valvoline 20w50 so I put that in. I assume since it's 100+ and air-cooled this oil would be fine.

 

[Kamele0N]

Yes.....its totally fine!!!

 

[Linctex]

Yes... even straight 30W (Like Rotella T1) will run that engine just fine.

I'm currently using "clearance" 10W-40 oil in mine, though I usually run 15W-40 "truck oil" .

 

[fdcg27]

In your climate, I'd probably favor something like a 20W-50 grade, although I'd prefer M1 15W-50.
I've used both Valvoline syn 20W-50 bike oil and M1 15W-50 in my OPEs and they seem to do well with either.
Considering how hot these little air-cooled guys get in warmer weather, I'd personally consider the recommended thirty grade too thin.

 

[philipp10]

Originally Posted by fdcg27
In your climate, I'd probably favor something like a 20W-50 grade, although I'd prefer M1 15W-50.
I've used both Valvoline syn 20W-50 bike oil and M1 15W-50 in my OPEs and they seem to do well with either.
Considering how hot these little air-cooled guys get in warmer weather, I'd personally consider the recommended thirty grade too thin.

then why are they recommending 30 grade?

 

[talest]

I think you are okay there, Chris142.

 

[Cujet]

Originally Posted by Chris142


I had some Valvoline 20w50 so I put that in. I assume since it's 100+ and air-cooled this oil would be fine.


It is a good thing to use a robust oil in air cooled generators. Here in hurricane central, I typically use 15W-50 M1, and change regularly.

I learned my lesson with hard working, air cooled engines under insane conditions. Trashed 2 Honda engines, running them 24/7 at full output. Generators work exceedingly hard when heating water or running the AC. It's not unusual for oil temps to exceed 265F, even on Honda/Kawasaki engines. (that's way above the operating range of most low viscosity, low HTHS automotive oils)


Let's look at it another way. An HTHS of 3.8 or so is sufficient for hard working air cooled engines. In years past, the recommended straight 30 was pretty darn close at 3.5 and it's a very shear stable 3.5. The 5W-30 so common today may test below 3, and be less shear stable. Not a good choice for the OP.


HTHS being the viscosity at 150C/302F.

 

[Chris142]

Originally Posted by Cujet
Originally Posted by Chris142


I had some Valvoline 20w50 so I put that in. I assume since it's 100+ and air-cooled this oil would be fine.


It's not unusual for oil temps to exceed 265F, even on Honda/Kawasaki engines. (that's way above the operating range of most low viscosity, low HTHS automotive oils)


thanks for posting actual numbers. I think I will switch it out at for synthetic oil next time as a precaution.

 

[Whimsey]

Originally Posted by Chris142
Originally Posted by Cujet
Originally Posted by Chris142


I had some Valvoline 20w50 so I put that in. I assume since it's 100+ and air-cooled this oil would be fine.


It's not unusual for oil temps to exceed 265F, even on Honda/Kawasaki engines. (that's way above the operating range of most low viscosity, low HTHS automotive oils)


thanks for posting actual numbers. I think I will switch it out at for synthetic oil next time as a precaution.


You sound like a good candidate for Mobil 1 15W-50. It'll take the heat. If you can pull start the gen with 20W-50 conventional oil then the synthetic 15W-50 should be easier to pull start. The only thing using a 50 weight oil MIGHT give you less run time for fuel used. But with your heat that's a moot point it seems

.

Whimsey

 

[DoubleWasp]

If you look at the generator manufacturers who really get detailed on their recommendations, you will find that 5W-30 is preferred for subzero, SAE30 for normal weather and conditions, and 20W-50 for high heat and extended operation.

Most of these engines hit the oil pretty good with the fuel dilution when being run hard. A thicker viscosity oil is preferred. Go thick and change often.

 

[Lawn_Care]

Originally Posted by Linctex
Yes... even straight 30W (Like Rotella T1) will run that engine just fine..


For summer use - I'll go against the grain on this one. Working on cleanup from Hurricane Katrina, I saw quite a few (and talked to many owners of) generators that failed due to overheating (most likely candidate) from near-continuous use in horrible Louisiana summer weather - swamps, humid as can be. Most of these generator owners were using 30-wt oil, because that's what their owner's manuals recommended.

Those running a 40-wt (or higher) had a MUCH lower failure rate running in those conditions for days on end. (actually weeks)

All of my OPE gets a 15w40 and a 5w40 in the winter - and that's in the St. Louis area.
If I lived much further south, I'd run a 20w50 in the extreme heat of the summer.

 

[Astro_Guy]

My Champion 3500 Watt generator calls for 5w-30 synthetic from -20 to +120 degrees F. It also calls for dino 10w-30 from 0 to 120 degrees F, and dino 10w-40 from 70 to 120 degrees F. My post warranty interpretation of that has been to use synthetic Rotella T6 5w-40 year round for the last three years. My generator does not see a lot of run time hours, but it is my only piece of OPE that might be called upon to run at either zero or 100 degrees F. The synthetic 5w-40 allows for easy pull starting in winter and also seems to keep it running smoothly in the summer heat. If I were to reach two days of nearly continuous running in summer heat with no end in sight to the power outage, then I probably would change to a thicker oil. Hopefully I won't need to worry about that any time soon.