I just had my oil changed in my 1990 300D TurboDiesel and the place where I had it changed recommended Valvoline synthetic motor oil (5W-30), so that's what they used. I haven't had this car long so this is only the 2nd oil change I've had, and the first time (about 2,000 miles ago) they also used synthetic oil, but someone who claims to be pretty knowledgeable about diesel engines told me I used the wrong oil and it could actually harm the engine. Is this true? Should I be worried about this? Or should I just switch back to a different oil on my next scheduled oil change? The car only has 100,000 miles on it, so I want to make sure I'm using the right stuff.

Thanks,
Jeff

 

Well, I checked Valvoline's website (I also called the shop where I had it done), and the oil that was used is fine for this car (may not be best, like the Premium Blue Extreme Engine Oil, but won't harm it, either). From the PDF on their site:

 

Well, many people think that a 30 weight oil is too light for our older diesels.

Plus, the oil you used I think is CF rated. Modern oils are CI-4 and CJ-4 rated.

So will 10-30 harm your engine? I don't know for sure but oil is relatively cheap (compared to engine damage). You might be better off getting yourself some 15w40 or 5w40 diesel rated oil. You can keep the old filter in there since it is new it sounds like but be sure to drain the oil filter housing so that you can replace as much of the oil as possible.

I use a 15W40 dino in mine btw.

I think we have the same engines, 2.5L?

 

diesels have much higher compression so a higher shear strenght is needed. That is were most of the oils fail which will lead to rod and main bearing failure. thats why your looking for the diesel rating

 

I'll go along with that but the shear strenght is also part of it.

 

FI,

Not to hijack the tread, but
What makes Rotella "Junk" ? I am currently using 40 Wgt in my 6V92TA, which was recommended. Alot of reasons I am still using the 2 stroker, but I will continue until it dies, not economical to replace otherwise.

Thanks,

 

You make me laugh on the 2 Stroker being a leaker. Many are just that, mine is tight, and if I keep the speed down (64) it burns less. It was a recent (less than 30K) rebuild at Stewart & Stevenson, Denver.

I use the Rotella, cause it is diesel rated & the straight 40W. It meets, albiet barely, the rated requirements, and I replace every 12K or 12 months. Any suggestions on alternate straight 40 wgt ??

I do only use Mobil1 in my '99 E300D. Been replacing @ 10K, but thinking of going to 15K miles, as the dealer recommended.

Thanks,