Piston ring soak?

[JOEPRO]

I have a 1990 Mercedes 300E-24 with the straight 6 m104 petrol engine.

It has sat around for over 10 years now It's starting to smoke when started up I think it's maybe got a stuck ring or two from sitting around.

Are there any recommended products in the UK I could remove the plugs and pour a little into each cylinder and let it soak for a week or so before starting the car again? I can drain and change the engine oil after this is done to flush out whatever product is used.

 

[dave h 2]

It's got compression on some cylinder's at least or it wouldn't start at all.
Hopefully this is blue smoke. Cause white is either a new bloke dressed in white or the head gasket has gone.

Pull a plug in turn when running and see if the smoke goes.
If the smoke goes after running a while or leaving traffic lights it's the valve guide seals.
Don't forget if you end up using stuff to free the rings it removes all the oil on the bore walls.

 

[Barking Mat]

Atf and acetone.

 

[james butler]

was going to say atf and diesel

Atf and acetone.

 

[Dozzer]

Another for ATF & Acetone, the Acetone is only used to thin the ATF to get it into the rings.
you can use anything that will thin it.

 

[JOEPRO]

Thanks all, yes it's burning blue smoke so engine oil. The engine had a top end rebuild some years back. Pics from the time- still had hone marks in the cylinders. Only did about 5k miles since that

 

[Kram]

Stick a bore camera down the holes. I can only think that rings may stick due to rust in the grooves and thats not coming out with ATF.

3 options as I see it.

Do a few miles and it may clear up.

Strip it and manually clean the ring groves, reassemble. Thats the only proper fix?

I watched a video a while back, that Merc experimented with some cheaper bore coatings, to avoid liners or nikasil, and they were not all that durable. Is this engine, one of those?

 

[tom2207]

run it on two stroke mix for a while , good quality fully synthetic I use Silkolene ,,, good for the rubber seals too , if youve time to soak it ,,,, has to be a drop of ....ACF50

 

[8ob]

The bores dont look in good shape, they have had a hone down them at some point and its left witness marks on the high spots.

Bob