I know the diesel specs go back to overlap with what we call PCMOs, Most PCMOs carry some old light diesel specs. So, where is the dividing line in regards to the Forums? Is it just that this area is for the same PCMOs that are dual-rated and the HDEO forum is ....umm. That's where I am lost because HDEOS are dual-rated too, most of them that I know of.
Are diesel PCMOs different from HDEOs?
- Thread starter Audi Junkie
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Diesel oils are usually a bit different. Many aren't as friction modified I believe and they usually had more ZDP although that is now changing also. For older engines with flat tappet cams, many diesel oils are preferred because they have higher levels of ZDP. Strong detergency also.
typcally a Multi fleet HDEO/PCMO has a higher TBN and more dispersant.
a Regular PCMO only less YBN and less dispersant.
FM can be in either depends on low temp vis grade as in 0,5,10W.
bruce
a Regular PCMO only less YBN and less dispersant.
FM can be in either depends on low temp vis grade as in 0,5,10W.
bruce
Based on my own situation, I categorize motor oils as:
--HDEO (such as Rotella).
--PCMO (such as any conventional or synthetic oil with an API SL or SM but lacking a CI-4 or CJ-4 rating; most synthetics will be CF rated).
--VW 505.01 for my PD engine. It doesn't matter what the API rating is. It so happens I'm now using a mix of Castrol 5W-40 and 5W-30 rated SL/CF in the VW.
So oddly enough, I'm running CI-4+ HDEO oils in two gasoline engines while running "only" CF in the VW TDI. Go figure.
--HDEO (such as Rotella).
--PCMO (such as any conventional or synthetic oil with an API SL or SM but lacking a CI-4 or CJ-4 rating; most synthetics will be CF rated).
--VW 505.01 for my PD engine. It doesn't matter what the API rating is. It so happens I'm now using a mix of Castrol 5W-40 and 5W-30 rated SL/CF in the VW.
So oddly enough, I'm running CI-4+ HDEO oils in two gasoline engines while running "only" CF in the VW TDI. Go figure.
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