best engine oil???

[dieselwagen]

what's the best oil to use on diesel engines?
regular or synthetic?
5w/40 or 15w/40?

[DCC]

I use Mobil S semi-synthetic oil, with a 15w40 rating (warm climate, slightly worn engine).

I think in USA you have Mobil Delvac 1 available (fully synthetic), which is a reformulated Mobil 1 intended for diesel engines.

[jtanguay]

probably the best oil is ELF (now Total)

if you have a diesel just make sure it has the C rating (compression ignition engine)

i think its CJ-4 or something now??? the old manual for the 1.6TD's said CD oil, and even had a sticker on the valve cover.  i don't know if the non aspirated diesels had this warning though, as there isn't really the same problems as oil coking up in the hot turbo.

i'm currently running amsoil 5w40 100% synthetic (full synthetic does not mean 100% synthetic btw) diesel oil.   it's designed for ultra low emission diesel engines, meaning it can cope with more soot due to EGR systems, but since my car doesn't have EGR, it just means i can leave the oil in longer.  oil change intervals if used with the EA filter is about 25'000km or 1 year.  i'm using that filter & their oil so i'll take it for a year.  works out to be cheaper than doing regular intervals with dino oil, and is better for cold starts, and doesn't coke up as bad (if at all?).

other oils should net you good oil change intervals, especially mobil 1.   i was using their 0w40 and 5w50 before this, and i noticed almost no oil burning with the 5w50 (my engine has a little piston slop, but new rings, and only burns oil when i go above 10 psi boost), but it didn't specifically say designed for diesel engines.  it just had the compression ignition certification, which is what matters.

i just like the idea of using amsoils EA (absolute efficiency) filter.  its a high flow filter that filters down to 15 microns, whereas other filters only go to about 30 microns.  only way to get even deeper removal from 15 microns is through bypass filtration.

[Possum79]

Im in California and all I can really find is Chevron CJ-4 (15w40)and Shell's Rotella T stuff. If your looking in store and not online that may be all youll find. I havent found anything else but I havent looked hard.

I use the chevron CJ-4(15w40). You can get it anywhere, even at walmart.

I have some blow by(or at least I think I do-havent compression tested yet) but It hasnt eaten much oil sense my last change. 1/2 quart or a little more in 1k miles.

[Ziptar]

I think in USA you have Mobil Delvac 1 available (fully synthetic), which is a reformulated Mobil 1 intended for diesel engines.

Yup, we do. Mobil Delvac 1 Synthetic is also sold in quarts and 4 gallon jugs as "Mobil 1 Turbo Diesel Truck 5w40". It's what I use in the TDI and TD. I've found it at Advance Auto Parts in quarts or 4 Gallon Jugs at Wally World.

[Matteo]

Am I correct in assuming the Synthetic is more desireable in an IDI engine also, for longevity. Can you filter and reuse?

[dieselwagen]

thanks for all the reply,
my car is due for oil change before the end of the month, and my diesel engine will find out what synthetic taste like..

[Pat Dolan]

For those of us who are faced with the ugly reality of cold starts, Delvac 1 (5W-40 "real" synth) is available almost anywhere with a little searching.  It is also useable fleet wide in gassers as well.  I use it on everything except real beaters (15W-40 dino) and race karts (0W-20 synth).  Don't think it is qualified for PDs though.

[rallydiesel]

I use Rotella T SB 0W40. Works well.