Good day,

Please your help
I just noticed from the the API Motor oil guide that categories CI-4, CH-4, CG-4, CF-4 are recommended where the older versions are required including the former API CE and CD; however they don´t list the API CF.

The description of API CF is "For off-road, indirect-injected and other diesel engines including those using fuel with over 0,5% weight sulfur".

What is the reason that API CI4, CH4, CF4 don't include API CF . What could happen if API CI-4, CH-4, CF-4 are used in engines requiring API CF, considering that sulfur content is < 0,5%

Thanks in advance

Hi Enrique,

Please see this PDF, third page. It shows the retrospectivity of the diesel specs.

http://new.api.org/certifications/engineoil/categories/...gineOilGuide2006.pdf

Although they do not explicitely mention the CF at higher grades, they do refer to CD, which is a predecessor.

API CD was the original spec for turbo charged diesel engines, the engine used in validating became obsolete and so engine oils could no longer obtain this useful spec. API CF was as near to this spec as could be achieved using a different test engine.

The CI-4 is backwards compatible to all but the 2 stroke engines where the CF-2 is required.

True, but I would be careful using a CI-4 in a API: CB engine ;-)

I assume EM is relating to Bore glazing in nat. asp. and lightly turbo charged diesels. I'm a bit out of touch, but assume the problem is still about.(in the UK still some old buses in use)EM or others might like to confirm?

@:Roger

I was more aiming on the fact that older engines which require API: CC or even lower can have problems with sealings/gaskets when using a pretty doped oil like CI-4.
Sometimes an OEM limits the quality of the oil in its recommendation.
For example the Nissan Terrano II from 2002, diesel, is limited to CF-4 as a maximum, which means you may not use a CH-4 or CI-4. I'm not 100% sure if this is to prevent glazing, I have to dive into some archives and get back on it...

Well that would make the API system pretty useless then since each newer category of oil is supposed to be backwards compatible. I can't say I have ever run into something that said you couldn't use a newer oil. I would be very interested to see that.

Well it can be said for practically every classic from before '65, at least for European brands...

I'm not saying that the retrospectivity of API must be doubted, but possible reaction with materials in seals and gaskets is often forgotten in these cases, so therefor it's advisable to be extra careful when using a brand new (high API) oil in a old (low API) engine. This risk can vary per company as each has it's own phylosophy (thus base oils + additive packages) to meet the API approval.

I use CI4 Delo 400 or Delvac MX in two engines which are quite old in design. One being the MB OM616 IDI turbo and other being the HINO W04D DI, the HINO has crossed 178000 miles and the OM616 has crossed 110,000 miles exclusively on Delvac or Delo since day one of ownership and I have not had a single issue of leaking seals or glazing. My engine internals are pristinely clean and my cams hardly show any wear. I have no oil consumption issues whatsoever at all.

Like I said, it depends on OEM and Oil. Mobil has one of the best baseoils, that can help. And my reply was more an advice, not a fact...