Oil recommendation needed for Van-air w/ Kohler CH18

[Hohn]

OK, Interesting info. LS JR. did not point out this nuance. Do you know which oils are dual rated? It has an API rating on the package starting with an "S"? Not to extropolate too much here, but I am going to assume all of these guys on tractor and small engine forums suggesting everyone to use a diesel oil in their small air cooled gas engines do not know the difference you are pointing out.

I can see how that type of oil appeals to a fleet manager. They can inventory fewer oils.


Keep in mind this is a small air cooled engine. I would be willing to bet it has flat tappets. Kohler does use roller followers on larger water cooled engines. You may be able buy aftermarket roller follower kits for these engines. This is what the racing guys do. I doubt it was speced out on this Van Air application. But I do not know for sure..

At this point, I think the OP has his answers.

Yes, on small engines most are still flat tappet because of the cost of rollers and the absence of CAFE rules. You are correct that an API rating with "Sx" indicates gasoline suitability ("S" for "service", not "spark" as is commonly held).

Chevron Delo, Valvoline Premium Blue, and some grades of Delvac (1300 super) are all dual rated for gasoline and diesel. You can even get full synthetic 15w-40s that are dual rated now.

The gasoline-rated HD oils are a hidden gem because the higher viscosity gets an exemption from many of the neutering effects of ILSAC and Energy Conserving designations. So an API rated 15w-40 or 5w-40 is almost always a better oil by additive package than a 5w-30 or 5w-20 in the same or similar product line. This is because the formulator isn't obliged to honor arbitrary rules like capping Phosphorus at 800ppm; they can set it wherever their own testing deems it appropriate.

Valvoline's full synthetic 15w-40 Heavy Duty oil carries all the usual and expected diesel certifications, but it also meets API SN and has a very stout full-SAPS additive package with 1100ppm phosphorus and 1240ppm zinc. The 5w-40 full synthetic Premium Blue also has a similarly stout, full-SAPS additive package.

The Delo 400 XSP is a similarly excellent 15w-40 with very stout full SAPS additive package (1100ppm phosporus, 1200ppm zinc) and also meets API SN Plus.

Finally, Delvac 1300 Super in 15w-40 meets API SP. It's a 0.9% SAPS oil that, while only a syn blend, is an excellent overall choice and is probably the champion of performance-per-dollar on normal drain intervals. It's excellent but cheap enough you can drain it without feeling guilty.

 

[diesellover]

I used to service Miller / Lincoln equipment and most were Kohler. Did you look up the engine / equipment manual?

Most of the time we would use 10w30 SN oil but if it was mine I would use 0/5w40 or Valvoline Restore and Protect 5w30 (very impressed with that one).

I will make sure to thank you. I am very familiar with the ch-18 manual, specs, and such from the build date of my 1994 cub cadet era and there may be differences with the van-air kohler engine so it never hurts to research.

 

[diesellover]

Sorry for the screenshot regular picture will not upload. For now at a 100 hr oil change service I'm going to use 5w40 with an SN rating. Due to where I live it's still dipping below freezing so I need something with good cold flow characteristics. In addition, after may I plan to change it to something else with long-term plans for warmer weather like a fully Synthetic 15w40 with an sn rating or something else. (15w40 is a better long term oil than 0w40 or 5w40 when considering the additives required to make that large viscosity change. Although I am no expert.)

This fram oil is the same as the argos. Even has basically the same part number. For what it's worth, advanced auto was paying to use the fram name and has now stopped paying for it so this is marked down in price.

I tend to believe the previous tech that drove this service truck used 0w40 European oil because I found the jug in the truck. However I don't know what oil is actually in this truck so I bought the new 5w40 jug.

Thanks for the replys! Loaded with info on cold vs warm and appropriate hour intervals between oil changes.

 

[Sam_Julier]

Mobil I 5W-40 Turbo Diesel Truck or equivalent year round.