My 850 runs great and burns no oil! Recently a mechanic said "With 185,000 miles, You should change to synthetic Oil" Like a FOOL I listened, it burned four quarts of oil in 3,000 miles, a freind says it was due to the synthetic oil being thinner and leached past the oil rings and out the exhaust.
Probably cleaned up the inside a bit , hope it didn't loosen anything big enough to clog an oil port or filter on the pick up.
Arghhh !
Any Ideas, suggestions or comments?
Did I ust take 50,000 miles off my babies life?
Mick

 

I would drain the oil and go back to your old oil. Going to synthetic at 185K is a bad idea.

 

I did change the Oil and went back to the old oil. Thanks. what about loosening big chunks of crud that are going to cause the bearing failure or ?
FOOOK!
Mick

 

I do not believe there was damage done to your motor.

I would change out the filter too, and use heavier weight oil (10W-40).


JPN

 

You are not a fool using synthetic oil, just need to use the right one. Try high mileage synthetic, in which chemicals are added to swell the seals.

 

It is a common misconception that suynthetic oils are thinner than conventional. If that were true, then it wouldn't have the same rating, would it? If you buy a high mileage 10W-40 synth, it will have the same viscosity as conventional 10w-40 (even better at high temperatures)

 

It is always good to search this forum before you do something to your car. This subject was discussed many times. My conclusion is: Don't do synthetic switch on high millage cars or do only with ''high millage synthetic". Synthetic oil has additives in it that dissolve organic buildup and that may result in leaks.
Hope it worked out for you after switch back.

 

hm. my 83 240 turbo wagon uses full synthetic 10w30 here in texas. the particles in synthetic arent smaller, theyre all *the same size*. in conventional, the particle size is varied. not by much, mind you. i burn maybe 1/2 quart of oil between 4k mile oil changes (i dont drive the brick that often anymore, so ive cut back from 3k mi oil changes)

i run my 850 non-turbo on the same, mobile 1 full synthetic 10w30. if you blew smoke after you changed to synthetic, its very possible you have bad piston rings, bad valve stem seal rings, bad rear main seal, bad oil pan gasket.. basically a number of gaskets could be on the verge of failing.

i would get it checked out. there is absolutly no reason you should start burning oil by just switching to the same weight oil, only synthetic.

you should never have 'big chunks of crud' in your engine. if the synthetic oil knocked it loose, good! it didnt belong there. all it was doing was masking an underlying problem, IE a blown piston ring or some other seal in your engine.

 

Here is one thing that I heard though, might be a myth...

Someone told me that Mobil 1 very silently changed their products and the Mobil 1 Synthetic isn't really a full synthetic oil, it is now a blend of synth and conventional.

Myth or truth?

 

i would say myth. theyre the top name for oils, next to royal purple.

 

I run amsoil 5w40 european car formula and i havent noticed any excess oil loss and i switched at 160k on my 850. its all in the oil you buy.

 

I would like to know the "someone"'s background, knowledge levels in automobiles and where he/she's got that info. I would say it is a myth but then I do not have oil analyser so I am not 100% positive. However, if Mobile Full Synthetic oils were really synthetic blend, it is a fraud and they got to be on some drugs to push their luck that far.

As already stated, synthetic oils are not thinner but have better lubricating characteristics. They are usually most suitable for extreme heat & pressure conditions (jet airplanes' gas turbine engines use synthetic oil; Mobil Jet-II, BP2197, BP2380, etc...). Engines with turbocharger/variable valve timing mechanism would be most suitable for synthetic oil.


JPN

 

Ok...disregard my last thought about synthetic being just as think as conventional.
Maybe it is thinner...
I have owned my car for 6 months. It has always had a leaking RMS...I switched to Mobil 1 10w40 High Mileage and thought everything is business as usual - still leaks the same.
Maybe it's leaking more than I think. You don't notice it on short distances, but today I drove 400 miles and I think I lost about 0.5qt. I'll be able to tell exactly how much in the morning. It's not burning it, it's definitelyy leaking. Damn RMS!!!

 

The RMS is known to leak with age/mileage. A member by the name of Robrike has posted a great write-up on RMS replacement with pics.


JPN

 

I changed my 850 to Amsoil 10-40 in March. I noticed a performance improvement right away.
Don't put too many miles on it, but I notice when I crank it to 5k through 1st and 2nd to keep it cleaned out I do lose oil pretty fast. Under normal light-foot driving though it still seems to hold oil quite well.

Related question: Will a clogged PCV cause oil loss? I'm beginning to notice fumes that
remind me of crankcase vapor.

When I bought the 850 last November, I did a finger sweep in the tailpipe and the finger was plenty black, I could see the soot. I still have that. I assume that's what's left of oil that goes through the combustion chamber.
JB

 

YES!
In fact, it is the root cause for the RMS leaking and others. You might want deal with it before your RMS goes.

 

Hello,
I have much more bmw experience but I am constantly amazed at how similar parts and oem providers are the same for the two makes.
Anyway, after paying 95$ for a mobil1 oil change in dallas I decided to go back to home oil changes. I have 01 s40 and s80 and 3 and 5 series bimmers and a 4xsuburban in the family all with well,an average of 120,000mi
SO I put 10w30 valvoling synpower in the wifes s80, which BTW had a new head at 85k after premature belt failure (3k miles BEFORE expiration of extended warr!!Yeah for once it worked!)but it should have top end oil issues
none of the cars ever used oil,(actually the 5 series has aleak from the oil breather assmbly) frankly, I hardly ever check it, that's an old timers habit with modern casrslol) Now in two days, to austin and back, 450 miles, it used 1 1/2 qts. I know cause I checked as she started out and was surprised it was low so I added some up to 1/2 down and today it hardly showed on the dipstick. I changed it a month ago. IT IS NOT dripping it except maybe some on the exhaust cause there is a hint of that burned oil smell but it is NOT dripping from the filter thanks, and leaves no wet spot. I haven't driven behind it but it does not fog the neighborhood going down the street either
So, I will change it back to a 10-40 castrol conventional or something and see.
I put a new o2 sensor on the s40 today of my daughters and oil was on the list but I decided to hold off.
And also, yes the particles may or may not be different, the rating is the flow characteristics at various temps, related to but different from film strength. Yes synthetic is a bit more consistent in size. It is the detergency of the synthetics that causes the leaks, and maybe a little difference in the capillary flow but no they are not thinner.
The mention of "loosening chunks of crud holding things together" reminds me of the debate on changing auto trans oil at high mileage IF IT HAS NOT BEEN DONE IN A LONG TIME. We did that on the s80 at 120k, but it had been done at least once in the 50k to 100k window.so far so good
We will see.

So, thats the long version. My question is;
bmws have been sent out the door with all synthetic since about 99-01, and thats all one is suppossed to use.
What oil are volvos born with? what did the dealer use when we took it there under warranty? Have these 01s not had synthetic in their youth?
What do you all volvo enthusiats use mostly?

 

this is frustrating
you guys mention rms??
I searched and it doesn't want me to find it, caps or not,
with spaces before and after??
something that a failed pcv valve will cause to fail?
like an oil separartor from the blowby perhaps?
thanks

 

rear main seal = RMS