10W40 in Air Cooled Engines - What Happens?

[Best F100]

Calling all Air Cooled Engine users. Landscapers, Porsche owners, contractors, doesn't matter. I've got a question for you:
I know many air cooled engine manufacturers recommend either a straight 30wt or a 10W30 (synthetic).

I have a 13kw, air cooled, Generac generator that is used for power outages. Manufacturer recommends a 10W30 year round. 2 quart oil capacity with filter.

In my local Kroger grocery store, I scooped up 6 Havoline mineral based 10W40 in the clearance bin for $1/qt. I know Havoline produces some of the best UAO's in a car. But what will happen if I try to use this in my generator year round, here in Michigan?

Background on this generator:

- If I use Mobil 1 10W30 (as most owners do), the generator will run until oil is "consumed" (around 24 hours into a power outage), and the generator will shut itself off with the "low oil level" light glowing. So you need to go out in a 10F icestorm and refill or change oil & filter. Same refill deal on a 85F day (after 20 hours).

- If I use straight 30 wt. It works great (is cheap, & stays in the generator) until winter rolls in. Then you have start up issues.

Questions:

A) Will a 10W40 work as well as a 15W40 HDEO that is commonly used in air cooled engines? (Being cheap to buy, good protection at high temperatures)

B) Will the 10W40 be "pumpable" down to 0F?

C) I know the 10W40 will shear (to a 30 wt - maybe a 20wt?). Will that cause a problem that I would notice longterm?

 

[Oldmoparguy1]

The only way you will ever know is to try it. Won't hurt it any, probably won't see much difference from your 10/30. In your place, I would use a good syn 5W40 HDEO like RTS or Delo, won't cost that much more and should stay in the engine.

Having said that, I run M1 10W30 in all my lawn equipment with excellent results, but I don't have to run them in the winter, and the winters down here are quite mild anyway.

 

[Pete591]

I tried Amsoil ASE 10W-30 after using M-1 15W-50 Goldcap. The engine has 500+ hours on it. Was smooth and quiet with 15W-50; clanky with tappett noise on the 10W-30...back on 15W-50 it's perfect again.

My .02

 

[kd5byb]

I just changed the oil in my 12.5hp Kohler-powered John Deere tractor with 5W-40 Rotella T Synthetic. Seems to work fine. Can't really tell if it's any better or worse than the Mobil1 10W-30 that was in there. Might be a tad quieter with the 5W-40, especially at idle.

I will note that the 10W-30 was extremely dirty. Usually I don't do mid-season changes like this as the mower is run less than 50 hours per season...

later,
b

 

[Pete591]

Amsoil has 0W-40 ATV oil; I used it in a Briggs 16HP v-twin..runs great.


0W or 5W is best for winter below 30*F

 

[addyguy]

10W-40 is 'pumpable' down to about -30 deg. C....so it will be fine in the cold.

Modern 10w-40, especially Havoline, is good stuff. The 10W-40 grades will have slightly higher add levels than 5W/10W-30, so they will protect well.

For the price you paid, you got a great deal on a supply of oil that will last a while.....

 

[FrankN4]

My new John Deere called for 10W-40 so I use a 10W-40 motorcycle oil. I was going to use 10W-30 motorcycle oil but after eading the owners manual I decided to go with the 10W-40. I just got the mower in June. i changed the factory oil at 5 hours. I now change every 15 hours.

 

[Best F100]

Originally Posted By: addyguy
10W-40 is 'pumpable' down to about -30 deg. C....so it will be fine in the cold.

Modern 10w-40, especially Havoline, is good stuff. The 10W-40 grades will have slightly higher add levels than 5W/10W-30, so they will protect well.

For the price you paid, you got a great deal on a supply of oil that will last a while.....




Yeah, I know Havoline 10W40 is good stuff, and "May" pump down to -30C. (I think that temperature is a stretch). But what I want to know is:

1) Since it is an air cooled engine, is the oil overmatched in a hotter running engine? (because of of wide 10W40 spread, mineral base, etc). Liquid cooled engines are like "easy" women - no challenge.

2) Will all kind of nasty deposits be left behind if it has to run for several days at a time?