W124 M111 Head gasket questions

[columbiers]

Thanks. Yes, going to take it to be tested/skimmed as soon as somewhere is open after new year.
That's what I hoped, that pistons would be OK. I suppose if it was running with them before it will be fine once the head is back on!

 

[BlackC55]

Those dents are supposed to be there.

 

[columbiers]

Thats a relief!! Had a cambelt go before on a car which left similar looking dents in the piston, assumed it was the same. Thank goodness for that.

 

[Will]

Was about to say - those are not dents, they are pocketed pistons so that they clear the valves at TDC. Many cars/MBs have pistons like that

 

[grober]

Might just be the camera angle but that rear piston looks a lot blacker than the others? If that's the case that might just be your suspect cylinder. The gasket on the rearmost cylinder often goes on straight 4 engines= furthest from the water pump+ engine compartment air inlet so runs hotter?? Sounds as if the cylinder head gasket went before and a cheap and nasty repair was done- poor quality cylinder head gasket/ old stretched bolts reused/ failure to check the head mating face to be true=not warped and planed flat. All cost cutting which means repeating the exercise after 6 months. Unscrupulous or impecunious owners sometimes do this type of repair before moving the car on??

 

[columbiers]

Yes, that's my thoughts too. Bought the car a month ago-when i looked it over there was no oil/water mix and no overheating. there was a little white smoke which I put down to condensation as everything else seemed OK. The old gasket is certainly different to the new Mercedes one I bought...
Still, it was cheap enough and bodywork is very good. Once this is fixed it will still be a good buy and will hopefully then be good for thousands more miles

 

[streethawk]

Hi whilst off I'd re-lap valves and new stem seals as seems a half done job if you've took head off! Also get head skimmed by fly cutting on a manual milling machine with someone who knows what there doing! By that I mean clean rocker gasket face and only rest on parallels at each end of head front to back! as if there is any warp it will clamp strait and not under stress if the parallels were along the length. Done many heads as am aerospace engineer! But don't tell the boss haha.Never done a merc and hope not to do mine unless needed. I'd carefully de-coke pistons and stone top of block too! Plenty of rags and watch for foreign bodys scratching bores! I normally bring each piston to tdc an clean then suck bits out with an old Hoover then thick oil and as piston goes down the oil holds any other bits at top and then clean away. Hope this helps.

 

[kth286]

as a mercedes tech (master certified) who has been fixing cars for 40 yrs id like to say this about the ANY apparant head gasket problems on ANY car..When u get to be my age ive always tended to try usuual procedures over the years just to get a feeling for things that really work and things that dont..Ive honestly CURED MANY head gasket problems simply by retightening the head.. especially when i first started replacing head gaskets and noticing that the gasket really wasnt BAD (actuall sections missing from the material) almost all looked as though the combustion and or coolant was leaking OVER or under the gasket itself.. i also noticed that in almost EVERY repair the headbolts themselves seemed way too loose.. so as a true mechanic and not justa parts changer one time i tried tightening the bolts making sure i loosed each up up at least one turn before cinching it back down.. to this day i do NOT use a tourque wrench.. prefering to use common sense and i 3/4 inch breaker bar with an adapter down to half in.. let me say that out of several hundred... honestly at least 200 retourques the only mishap i had was once recently a bolt snapped onna 98 5cyl volvo . i was able to use a left hand drill bit to remove the bolt.. now im sure most of you will say im crazy and risking whatever damage or just plain stupid.,. but im just sharing with the forum what ive learned over the years.. i was the salary troubleshooter for 8 yrs at a MB DEALER here in Arkansas so ive discovered some programming tricks on later model benz's that WILL be of use to ANY owner of a MB from 92 and later.. i left the dealer in 07 so anything newer than that id not ne of much help.. but otherwise id be glad to offer my opinion of any dillemma presented to me..

You created a lot of interest I'm sure.

Question: when you say you first loosen each bolt first, and tighten down
again - do you mean you loosen all bolts one turn first, and then proceed to
tighten each bolt in proper sequence again ?

OR

do you mean you deal with one bolt at a time by loosening it and then tightening it, and then move onto another bolt and do the same; until all bolts have been loosened and tightened in sequence.

Thanks