Have a 500SEL with 192000 miles which has been progressively using more oil since about 140000-150000 miles and smokes so badly the car is no longer driveable. Valve job was done at 101000 miles but seals were checked and again replaced at 191000-no problem with guides or seals noted and no effect on smoking. Problem not likely related to guides or seals.
The engine has been dismantled and all looks good for the mileage. The only area that shows any likely cause of the problem is the oil rings appear to be worn noticeably.The expanders show wear at the gap and the ring has about .055-.060 end gap at the bore top. Max bore wear is only about .001 and the pistons and bores look very good.
My question is can we expect to resolve the problem by replacing the rings in this engine? It would help to hear if anyone has had a similar situation in one of these engines and successfully corrected it. At teardown this car was using about a quart of oil every 200 miles. Smoking most excessive cold and moderately accelerating. Any suggestions would be appreciated
Art Ziesk

It sounds to me like the engine was overheated at one time. I hope the tech knows not to touch the cylinders with any kind of machine. There are only a few places in the U.S. that can bore/hone these. I'd be curious to know of the overheating.

------------------
Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

If this car was overheated it occurred before I acquired it at 101000 miles. It had a broken guide rail which caused the chain to skip and bend valves on one bank. The oistons were not removed at that time and the car ran 40000-50000 without using any significant amounts of oil. It definitely has not overheated since nor even lost water of any significance.


[This message has been edited by Webmaster (edited 02-21-2000).]

I feel rather stupid but I found the problem after inspecting a new set of rings. The drainback groove openings in the oil rings were so badly plugged that it was not obvious that there were any openings. It required considerable scraping to expose the opening. We did try some cleaner prior to teardown but it would be virtually impossible for any solvent to remove this carbon. There is no doubt that a new ring set will restore this engine to normal for many more miles. I guess it is possible that this engine was overheated earlier in its life to cause such severe carbon buildup. It has had regular oil changes over the last 90000 miles and the interior of the engine was very clean.
Thanks
Art


[This message has been edited by Webmaster (edited 02-21-2000).]