bhpplease

Hey guys,

I have narrowed down my oil burning issue to worn valve stems seals. Engine is the M272.983 (CGI) Variant and 200k miles.

Wondering if I can do the valve stem seal job in situ in the car by taking off the valve covers and using "the roper method" to fill the cylinder to prevent dropping the valve?

Any body got any ideas or pointers?

The alternate options are just to throw some additive at it and let it run until it burns out the cats, or take out the engine and rebuild the head and probably pistons/cylinders too (because it's out).

How long does it take to burn out the cats? I am doing about 5k miles per year at the moment.

nota_amg

wait...burn out the cats??? huh? why would you think that would be something that would help your valve seals? It would reduce backpressure, but the valve seals will still leak. also, "burning" the cats out would take an enormous amount of heat and wold not be good for other components on the car. Seems like a really bad idea...

chassis

Remove the cylinder heads and rebuild them, have them rebuilt, or buy replacement heads.

bhpplease

Oh sorry for the confusion.

I was coming at this from a solution of last resort. Meaning that I don't pour loads of money into the car and just drive it until I can no longer drive it. By that I mean drive it until the consumed oil ends up burning out the cat and it fails the emissions test. Here in the EU we have a test each year. It passed without issue in September so there is another year at least.

I bought the car two years ago with 190k miles, i've done 10k on it (5k year) at a cost of £5k against usual market price of £12-14k. So economics comes into play here and could suggest that if I get another year or two out of it, could work out as not totally expensive driving.

Bit of a coin toss really. A pity though as I love the car and had planned on keeping it 10 years or so as a daily whip.

911st

My guess: If you do not want to have the heads rebuilt, do a leak down test to check to see if it is worth it. Most cars, and my old 190E, the stem seals are replaceable without removing the heads. But there is a lot of plumbing and electrical on the top of that motor that will have to come off. Not to mention the cams. Taking the heads off is not much more work (exaust and coolant). Me, I would rather cut my losses, sell with full disclosure and start over. Still, there is somthing to be said for doing no more than you have to and try for another 100k miles.

nota_amg

if cost of ownership is your main concern, this may be the best option, honestly. Or, try to find a used catalyst section of exhaust and just swap that out when/if the cats die?

Trevor Hadley

Use the thread from an old spark plug ,,weld this to a metal tube. Now you can fit a rubber hose on to the end with a good clip ,,it will need to be airtight.This then screws in to the plug hole , next thing is to pressurize the tube you made so the pressure holds up the valve your working on .No compresor dont worry remove an oldb tyre valve ,fit this to the other side of the rubber hose with another good strong clip ..it too must be airtight .Do this and check it after its been pressurized with a tyre pressur gauge you can do this with a tyre gauge to see if it is loosing pressure before you start the job. Good luck this can be done on conventional engines might be possible on yours ..

bhpplease

I'm not really interested in selling. I don't think i'd find a buyer that easy for a 200k miler that is burning more than it's fair share of oil.

I have considered compression + leak down tests.

Cost of ownership isn't really my main concern, but I don't want to start throwing thousands at this problem. I kind of figured that buying the car at well below the market price of a similar 100k miler, I was getting a good deal etc. (£5k versus £12/14k) I don't want to negate other wise it kind of makes this a fools errand, in my opinion.

I like the sound of swapping out the cat sections. Overall I really love this car. The colours, spec and that V6 really does it for me. In January I will have it 2 years and I have often said I will keep it for many years. I suppose with that attitude I should be doing the engine job. But on the other hand doing nothing and seeing how long I get might be the most economical.. There is something sorry about knowingly driving a car to it's death though.. especially a beauty of a MB V6 and the notion that 200k is "small mileage".

Imagine I rebuilt the engine. Whole kit and caboodle (Block + Head) inc valve train, timing pistons etc.. Is it fair to say the engine is like new and good for another 200k miles?

Very good idea.. the spare tire sure does come in handy.

Frank W

Wow congrats! Super clean low miles, not too many left out there.