I just bought a 1995 940 turbo wagon with 209,000 miles on her. Been maintained by a former diesel mechanic for the past 10 years. He uses Valvoline synthetic, and lucas oil stabilizer. He failed to tell me what weight. My question is...Does it need, or do you recommend staying with synthetic? What weight, and is the lucas a good thing or a bad thing?? Appreciate all suggestions.

 

10W30 full synthetic for turbos under most climate ranges.. I have been using mobil 1 for the past dozen years with good results so far, but any major brand synth is fine.

in the desert southwest in the summer, you might want a slightly heavier, 15W40 at most. in the arctic north, you might want lighter in the winter, but not by much, maybe 5W30 synth. otherwise, 10W30 covers pretty much the whole temperature range.

I never use any oil additives, any major brand synthetic oil is just fine, adding stuff to it just messes with its balance.

 

synthetic is better, period. If you can afford it, use it. Is it really worth the cost????? I can't say yes or no. No test data on engine wear over the life with both,.

Weight whatever the manual says.

Can't say ether way if an addtive is good or bad. Never seen an additive ruin an engine...... Use "cleaners" with no issues.

 

turbos TRASH oil..... you definitely should use a synthetic with them, conventional dino oil will coke up in the turbo after a hot shutdown.

a standard redbrick? geez, you could use crisco and it would probably last long enough.

 

coking is a thing, but it's over-hyped and misleading you had to have driven the vehicle super aggressive in boost immediately prior to turning off the car for it to be an issue.

 

your exhaust manifold is red hot after driving even at moderate throttle... all that heat bakes the turbo after the oil flow and water flow stop. I live at the top of a mile of 8% grade, and even if I baby my car up the hill, its pretty darn hot. I coast into my driveway and let the car idle for 30s or so before I shut it off, but that doesn't cool it off that much.

 

Synthetic is better considering today's technology. As far as cost, you go twice the distance so you save the change of the filter and the labor, so actually it's cheaper over the long run. I'd never use any additives unless I want to thicken the oil or some other short cut. 10-30 seems to work well in b230, I tried a little heavier oil, slowed the engine, lowered the rpms...

 

For any turbo car I would use nothing but synthetic. Any new car on the market today that sport a turbo specifies nothing else but synthetic oil.

 

My rule of thumb is synthetic every time, unless the car uses oil, in which case $7-9/qt can get expensive. Unfortunately, my turbo does use a bit of oil, so I go with the factory recommendation of 15w/40 conventional oil, which is the same weight that goes in most heavy trucks, like the Freightliner I used to drive. I use Delvac, but Rotella is probably good, too.

 

15w40 is a little heavy for these engines, and for the turbo, but its probably OK in texas summers.

 

So I am seeing this new mobile one extended performance synthetic that says you do not have to change it before 15000 miles or one year. Would that be frowned against in a car with 210000 miles? Im thinking so!

 

with a turbo I would not likely use that more than 10000 miles.

but I'd watch it, if it didn't turn nasty black, and still felt like it had decent viscosity, I dunno, I *might*

 

Well, I don't think the mileage on the car matters... Still, 15,000 miles is a lot! How much are they asking for that oil? Hard to say at this point--may be after a couple of motors get ruined... And even then it's hard to know for sure. Do what works. I usually wait for new technology to prove itself by all those "early adapters", then may be... I hear there are phones you don't need a cord for; I am waiting to see how that turns out before I take the plunge.

 

I had the same thought, but that's what's recommended in the owner's manual.