Rebuilding the 602

[Monomer]

I've got a '92 300d here that has one of three things: Blown head gasket, warped head or (I hope not) a cracked head.

She got me home. 120c does a lot to a car.



What else should I replace while I'm in there?
-Timing chain/Oil chain
-Cam gear
-Vac pump rebuild
-Valves
-Lifers
-Nozzles (OK, it's needed them since I got the car.)



Any other Engine mechanical I should look at? I want another 400K out of this car!

[oldiesel]

Before you remove the head check the chain wear by the dial indicator method,less than 4deg dont worry about it.Cam gear examine it carefully for wear and then decide.Lifters if you have no lifter noise when you start it after sitting overnight and none of the lifters are concave no worries there.If you find a lifter that is concave on the top where the cam pushes on it,measure that cam lobe carefully and compare it with a lobe that has a good lifter,a new lifter on a cam lobe that is worn will not last.Mark each lifter so it goes back with the cam lobe it has been running with,this is important! If your engine has been using oil it probably would be a good idea when you take the head to a machine shop to have it checked for warping assuming the head is good, have the valve guides and seals replaced.to do this they will have the valves removed and can advise you as to reface or replace them.Insist that they only cut the head if it really needs it and then the very minimum to true it! The Vacuum pump, take it off and inspect the bearings and the face of the timer part that it runs against,there are plenty of posts here for what to look for there.Im sure someone will have some good advice to add here. My $.02 Don

[Monomer]

It has a TON of lifter noise/injector noise.

[pawoSD]

How did you overheat it? What happened? Sorry to hear that!

[oldiesel]

something i came across when i first got my 2.5 that i thought might be a good method of diagnosing engine noises. As so many here had reported good results with diesel purge and even though i never put much faith in "mechanic in a can" i did give it a try,as soon as the diesel purge reached the injectors all fuel related Knocking (nailing) went away and all that was left was the sound of a nice smooth running diesel.Once it was back on D2 all the clatter and knocking returned as quickly as it had gone. My point being that if you are not sure which noises are real mechanical such as collapsed lifters or other internal noise try the diesel purge to eliminate the fuel related noise so you can hear what ever other noise there might be and you might be lucky as i was and not have any mechanical defect noise.If you are not familiar with the diesel purge method do a search her there are plenty of posts outlining the procedure.A new set of nozzles was all that was needed to eliminate all the racket,ihope you are as lucky. My $.02 Don

[Monomer]

Originally Posted by pawoSD

How did you overheat it? What happened? Sorry to hear that!

Blown coolant return hose. She didnt leave me stranded.



I've done DP on her a few times. Noise did not stop. The car has 421K on her - Due to neglected other routine maintenance; I'm sure injectors are past due.

[Hatterasguy]

Considering the mileage, and if you plan on keeping the car I'd get a long block.

The pistons, rings, all the bearings and seals are shot. If the IP and turbo are original those are due to. Everything involving the timing chain and oil pump is probably shot.

I'd swap in a long block, and call it good for the next 400k miles. Or send your engine to Metric for a rebuild, but that would cost more.

For a rebuild I would:
Send the turbo and IP out for overhual.
Send the head to Metric and expect to get all new valves, seats, seals, springs, prechambers, injectors and a new cam.
Pound the pistons out, send the block and crank to a good machine shop that knows Mercedes engines to see if you can use them. If so have the block re sleeved. Order all new bearings, pistons and rings. Also get a new oil pump. Replace all the rails, associated with the timing chain and oil pump chain.

[pawoSD]

Thats going to cost some $$$ Yikes.

[Hatterasguy]

Its a Mercedes, they are not cheap.

[pawoSD]

Originally Posted by Hatterasguy

Its a Mercedes, they are not cheap.

Very true. I know that all too well. I think its a disease. I haven't had to fix much on my car lately, so instead I've been buying and accumulating parts. I stripped a euro 500SEL of a huge amount of parts a couple weeks ago at the u-pick, and just bought a spare tranny w/160k on it and a nice heater core from a guy here locally....I need to stop!

Later this week I am replacing my aux water pump and thermostat. Something to fix! Horray! Maybe I will glue my glovebox wood back down too....and clean the car or something. With all the parts replaced it has become in too little need of fixing!

[Hatterasguy]

I'm starting to get the parts together to do the paint job/exterior resto. I just got the sill that sits below the rear windshield. I figure by the time I paint it next year I'll have most of the exterior chrome and seals on hand.

After the next closing I think I'll get all the chrome on the trunk lid, and around the rear windshield.

Little at a time.

Luckly a rock cracked the windsheild before I put it away, so when I paint it I'll get the insurance company to handle that.

[mcguirjf]

Sorry for your loss Monomer.

Before pulling anything apart get some compression numbers. If they still look close and around the 400 range do the head work, but if they are in the basement don't waist your money. When I purchased mine and got it running there was more exhaust out the oil cap than tail pipe. I found a 87 190D turbo engine with 90K miles for $800.

Best of Luck!

[pstutcher]

I'm sorry to hear about the catastrophe. I miss that old girl. Please keep us updated on the progress,

[Monomer]

Originally Posted by pstutcher

I'm sorry to hear about the catastrophe. I miss that old girl. Please keep us updated on the progress,

She'll get fixed.



I think you would have kept her if you figured out the boost problem she had. It'll get ripped apart when weather allows, then I'll either decide to rebuild or find another 602.