Originally Posted By: merconvvv
Originally Posted By: SonofJoe
Originally Posted By: Linctex
Originally Posted By: SonofJoe
.... any
light-ends boiled off ..... to the cylinders to be burnt. The sticky deposits left behind from the incomplete combustion of oil
Has this claim been proven, or just speculation?
I equate "light ends" (especially in vapor form) to combust quite easily,
and any deposits are usually not "sticky"
Shannow has just put up a link to an obscure book called The Chemistry of Engine Combustion Deposits. You can find it on Page 4 of the 'High Noack Oils And Dirty EGR Valves' thread. It was written by a guy from Exxon called Lawrence Ebert (we must have overlapped but I don't ever recall meeting him).
Anyway this book is a real page turner! I so wish I'd known about this before because it confirms a lot of what I saw when I was playing with oils. If you want answers to your questions, have a read and make your own informed judgement as to whether it's all speculation or not.
Used to run a lot of m1 0w40 etc and burn quite a bit and sure enough the egr ports had to be cleaned on the expedition at 120k miles. Ofcourse most motorcrafts oil are around 14 percent noack and the dealers clean quit a bit of egr stuff.
That's interesting, our '02 Expedition had zero burn-off between runs of M1 0w-40 when I ran it
The NOACK of the previous version of M1 0w-40 was 8.8%, which is quite low. Not sure what the new "FS" version is sporting in that department, but I believe it has to be below 10% to meet some of the approvals it has.
Also, I never cleaned the EGR passages and it had over 200,000 miles on it when we sold it.