Oil recommendation needed for Van-air w/ Kohler CH18

[diesellover]

Hello everyone. I have a van-Air in my service truck. It has a Kohler horizontal shaft engine similar to a ch-18. It's a v-twin but it's actually fuel injected and takes fuel from the service trucks gas tank to run.

These poor van-airs run often. Long idle periods in the winter. They operate as combination unit to run a high amp battery jump start, generator, air compressor, as well as being a stick welder!

Requirement for oil changes is every 500 hours which is crazy high. I'm going to change the oil and filter now at 100.

It previously had 0w40 European oil. What would be an appropriate engine oil for this air cooled v twin engine? I was thinking 15w40 fully Synthetic or 10 w40 fully Synthetic and an oem or other oil filter. A 15w40 is less likely to fall out of range due to the low temp and high temp numbers being closer...

But maybe there's a Lucas small engine oil or other small engine specific oil I should grab? These do require a multi weight oil. Still falling below freezing here.

 

[martinq]

What does Kohler spec for the oil?

If this is a new unit I would do break-in oil change at something like 10 / 50 / 100 hours. 500 hour OCI could be doable after that but it does sound like a stretch. If you want to be sure then I'd get the oil tested.

Personally I would run a quality 0/5/15w40 depending on your operating environment, that meets the spec from Kohler. What's the coldest ambient temperature for this unit during the year?

 

[38Chevy454]

I would suggest any 5W-40 synthetic diesel oil.

 

[Opelman]

Kohler has a full syn 10w50 blended by Amsoil 25 357 72-S specified for long oil change intervals. 300 hrs instead of the usual 100. There is a special filter too , 25 050 53-S.

 

[meep]

Pretty solid thoughts with a X-40 synthetic. Unless cold start is an issue I’d very much favor the 15-40.

 

[nbpt100]

How cold does it get in the winter when you run the engine? How hot in the summer? You can not wisely choose a viscosity range with out knowing this. You can run the Kohler oil and use the viscosity they suggest. Kinetix makes very good small engine oil 10w-30 or 10w-40. Someone mentioned Amesoil and I would not hesitate to use their products. If running more in hotter temps going to a 40 or 50 weight is common. It will reduce oil burning.

The Kohler CH-18 manual recommends an OCI of 100 hours. More frequently under heavy conditions.

Below is the Kohler temperature viscosity chart. The Kohler Pro 10w-50 is a full synthetic oil and they say you can have extended OCI. Upto 300 hours. I would not do that. I would stick with their 100 hour oci recomendaion. Or sooner.

I am not an oil expert but I listen to and read them. Tribologist Lake Speed Jr. says never use diesel oil in a gas engine. I know a lot of people will do it for the higher ZDDP(zinc) values. He had run tests and collected data that says it is not better. It showed more tappet wear. He emphatically says more ZDDP is not always better. It can be worse depending on the application. According Speed, Gas engine oils with viscosity OVER 10w-30 can have more ZDDP and still maintain the API rating. Both videos are a bit long but full of relevent info.

 

[thastinger]

Kohler's 10w30 is actually a good oil. A search on here will reveal a VOA of it. Same for substitute filters for the factory kohler filter.

 

[Fordiesel69]

Small engines will not experiance that ring land failure as shown in the video. Running a diesel oil in a direct injected gasoline engine may be a problem as he shows. I have ran T4 Rotella 15w-40 in all of my air cooled briggs, tecumseh, honda, kohler, and my vulcan 900 and 1900 stratoliner motorcycles without any type of lube related failure.

In your kohler ch18 you could also use a motorcycle oil. The jaso ma / ma2 rating will be of no use, but it does have awsome zinc and moly that will help the flat tappets in that engine.

 

[Fordiesel69]

And diesels usually have flat tappet cams with super high lift on their lobes. Diesel oil indeed protects them, so why would it protect a carbureted or port injected gasser?

 

[martinq]

Because this engine is EFI it probably has an O2 sensor and possibly a catalytic converter. If this is the case it would be wise to use a modern formula that is SN / SP rated. I'm sure this is mentioned in the equipment / engine manual.

 

[Opelman]

And diesels usually have flat tappet cams with super high lift on their lobes. Diesel oil indeed protects them, so why would it protect a carbureted or port injected gasser?

Most pushrod diesels have roller cam followers, even the updated Olds 5.7 in the 1980s.

 

[diesellover]

What does Kohler spec for the oil?

If this is a new unit I would do break-in oil change at something like 10 / 50 / 100 hours. 500 hour OCI could be doable after that but it does sound like a stretch. If you want to be sure then I'd get the oil tested.

Personally I would run a quality 0/5/15w40 depending on your operating environment, that meets the spec from Kohler. What's the coldest ambient temperature for this unit during the year?

Coldest temps are below 0 degs F. I just got this service truck a few weeks ago. I assume the 0w40 European oil was what the last guy put in the kohler (found a jug of it in the truck). Actually not a terrible idea for how cold it can get here. I'd hate to starve an engine of oil during a cold start due to having the wrong type in there.

Yes the 100 hour service isn't too terrible. I don't see the 500 hour service intervals though! Just not the best idea, but I do believe that's what most guys do unfortunately. I personally think 100 or something over that is plenty. I've gone 25 and 50 hours with my Kohler CH18 in my cub cadet. Air cooled engines really appreciate new/ clean oil! I mean it's only 2 quarts so I'm not sure why people skip oil changes on generators, expensive zero turns, snow blowers etc as it is.

 

[repairman54]

Since you do change the oil then 0w-40 for winter starts and 15w-50 for summer would be fine. and both oils should work just fine for the seasonal overlaps between changes.

 

[Hohn]

I would suggest any 5W-40 synthetic diesel oil.

As would I, especially one that also carried the API SP gasoline engine endorsement as well.

 

[Hohn]

Most pushrod diesels have roller cam followers, even the updated Olds 5.7 in the 1980s.

It's hard to find a non-roller engine now, diesel or not.

 

[Hohn]

How cold does it get in the winter when you run the engine? How hot in the summer? You can not wisely choose a viscosity range with out knowing this. You can run the Kohler oil and use the viscosity they suggest. Kinetix makes very good small engine oil 10w-30 or 10w-40. Someone mentioned Amesoil and I would not hesitate to use their products. If running more in hotter temps going to a 40 or 50 weight is common. It will reduce oil burning.

The Kohler CH-18 manual recommends an OCI of 100 hours. More frequently under heavy conditions.

Below is the Kohler temperature viscosity chart. The Kohler Pro 10w-50 is a full synthetic oil and they say you can have extended OCI. Upto 300 hours. I would not do that. I would stick with their 100 hour oci recomendaion. Or sooner.

View attachment 327596

I am not an oil expert but I listen to and read them. Tribologist Lake Speed Jr. says never use diesel oil in a gas engine. I know a lot of people will do it for the higher ZDDP(zinc) values. He had run tests and collected data that says it is not better. It showed more tappet wear. He emphatically says more ZDDP is not always better. It can be worse depending on the application. According Speed, Gas engine oils with viscosity OVER 10w-30 can have more ZDDP and still maintain the API rating. Both videos are a bit long but full of relevent info.

Let's not extrapolate too far from LSJr's data.

Diesel ONLY rated oils might not be ideal for a modern gasoline engine, especially if that diesel-only oil uses a very high calcium base that competes with the antiwear package.


But there are several "diesel" oils that use Magnesium-heavy additives packages and/or carry dual ratings as gasoline oils as well. They are perfectly fine to use in gasoline engines and a great choice for many small engines of precisely the kind at issue to the OP.

 

[nbpt100]

Let's not extrapolate too far from LSJr's data.

Diesel ONLY rated oils might not be ideal for a modern gasoline engine, especially if that diesel-only oil uses a very high calcium base that competes with the antiwear package.


But there are several "diesel" oils that use Magnesium-heavy additives packages and/or carry dual ratings as gasoline oils as well. They are perfectly fine to use in gasoline engines and a great choice for many small engines of precisely the kind at issue to the OP.

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.

It's hard to find a non-roller engine now, diesel or not.

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.

 

[diesellover]

Fwiw, I had my cub cadet engine apart twice, a Ch18s Kohler command. It has hydraulic lifters if that helps answer any questions about the top end. I've been told they are the same as or very similar to gm engine hydraulic lifters like a Chevy 350.

I've also read that due to the hydraulic lifters, it benefits from a multi weight oil. I had to research into that previously due to thinking a straight 30 was always best for Air cooled small engines in the summer time.

The engine does have an oxygen sensor and possibly a catalytic converter I believe. I know for a fact they have an oxygen sensor.

 

[BrendanC]

i vote to continue on with euro 0/5w-40 motor oils. before becoming an active member here all i used was 5/15w-40 diesel oils before learning about euro oils.

 

[martinq]

Fwiw, I had my cub cadet engine apart twice, a Ch18s Kohler command. It has hydraulic lifters if that helps answer any questions about the top end. I've been told they are the same as or very similar to gm engine hydraulic lifters like a Chevy 350.

I've also read that due to the hydraulic lifters, it benefits from a multi weight oil. I had to research into that previously due to thinking a straight 30 was always best for Air cooled small engines in the summer time.

The engine does have an oxygen sensor and possibly a catalytic converter I believe. I know for a fact they have an oxygen sensor.

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).