Howto change a head gasket on a 12v 3ltr M103

[grober]

Great post Ian-- immortality beckons --- at least in MB circles. Once everyone has commented and its tidied up--i.e. a few pictures of the cleaned up head +gasket etc and the rebuild details especially the timing chain tensioner reassembly sequence where many re-builders get it wrong and the "piece de resistance" -the completed rebuilt engine picture--- its should take pride of place in the HowTo section.

 

[dka-66]

I just found the site, read through this post, and had to register so I could ask if there has been any progress on this and if there has if the poster going to give an update.

 

[ps2cho]

Hello UK from California!
Got sent this link by dka-66 above me

I'm doing my first head gasket job next week and I am sure this thread will see me through everything!

Gotta get the gasket done on my 1988 300TE M103 engine 90k miles.

Just wanted to say thanks for the thread!

 

[ms500]

If only the M104 was as simple

 

[nick mercedes]

Hello UK from California!
Got sent this link by dka-66 above me

I'm doing my first head gasket job next week and I am sure this thread will see me through everything!

Gotta get the gasket done on my 1988 300TE M103 engine 90k miles.

Just wanted to say thanks for the thread!

Don't forget that you can leave the manifolds in situ, there's no real need to take them off.

 

[dka-66]

Don't forget that you can leave the manifolds in situ, there's no real need to take them off.

I heard it was a real pain to pull the head with the manifolds still on.

 

[nick mercedes]

I heard it was a real pain to pull the head with the manifolds still on.

Just lift it up.

Putting the head back needs two people to line it up.

If you strip everything off it you're just making work for yourself.

 

[coupe deville]

well done mate, good job, I wouldn't tackle that for immortallity in a french knocking shop

 

[ps2cho]

Don't forget that you can leave the manifolds in situ, there's no real need to take them off.

Ok I'll take your advice!

I start tomorrow evening

I have a oil pump seal to do as well....with the head off...how much more time would I be looking at to get at the seal?

 

[dka-66]

Finally got around to pulling the Head today and all I have to say is "Thank you"

I printed this out and kept it on the Fender.

Ian B Walker is my personal savior

 

[Ian B Walker]

I just found the site, read through this post, and had to register so I could ask if there has been any progress on this and if there has if the poster going to give an update.

As far as I am aware everything is ticking over nicely. Ask JPSKiller, it was and is his car. I always leave the exhaust manifold on the car as it gives you some purchase to break the head gasket seal. There is enough room to unbolt the inlet manifold and pull it to one side. Doing this helps with vac line assignment.

 

[Ian B Walker]

If only the M104 was as simple

Actually it is. The secret of a 104 engine is to set the crank at 30 degrees and lock the cams in the locating holes. After that, the procedure is very similar. However be warned that the chain idler cog retaining screw is a left handed thread. Next time I do a 104 head I will write it up.

 

[ps2cho]

I'm starting my Head Gasket replacement today...finally!
I'll let you guys know how it goes. Gonna try and take your advice about leaving the intake stuff on.

 

[ps2cho]

Mid way through. Coffee break!

Possible Misfire cause? Cracked!!

New Belt going on now

Gonna remove the head without the intake side attached. As far as I understand it is possible, but a little more tricky. Less removed = less potential lost items and problems in general.

Thinking of getting my valve cover and exhaust manifolds powder coated too. Silver valve cover and black exhaust manifolds. What do ya guys think :naughty:Mid way through. Coffee break!

Possible Misfire cause? Cracked!!

New Belt going on now

Gonna remove the head without the intake side attached. As far as I understand it is possible, but a little more tricky. Less removed = less potential lost items and problems in general.

Thinking of getting my valve cover and exhaust manifolds powder coated too. Silver valve cover and black exhaust manifolds. What do ya guys think :naughty:

 

[Dieselman]

I don't see how you're going to have the exhaust manifold powder coated, the plastic would melt and set fire.

The misfire could well be caused by the distributor backing disk, we had a member with just such an elusive misfire caused by it.

Keep plodding on and Have Fun..

 

[ps2cho]

Sorry I didn't mean powder coating...Forgot the name, but get it painted basically.

I hope that the distributor suppressor housing/backing disk WAS the cause of the misfire and the head gasket will leave me with a dead perfect, no-longer-leaking engine

Well...

Here she is!!

Here are each of the cylinders in order 1-6. How do they look?

Here is my coolant leak it looks like:

----------

Overall took me about 8hours including breaks. Didn't run into any major problems which was nice. A bit fiddly taking off the head without the intake manifold and items attached, but I think it was well worth it. Less hassle on putting everything back in.

Gonna take the head to a machine shop on Monday and get them to skim it and check everything over.

 

[ps2cho]

Where can I find the threaded Freeze plug that is for Cylinder #6??? All I find is the non-threaded one that goes on 1-5...but I need a new one for 6. Finally got it off and there is so much corrosion inside its completely blocked. That freeze plug was my coolant leak 100% sure.

 

[grober]

which of these do you mean? http://www.detali.ru/cat/oem_mb2.as...GM=717.433&CT=M&cat=505&SID=01&SGR=065&SGN=07

There is a threaded plug to the oil gallery on the rear end of the cylinder head???

part no 000908010004 screw in plug

part no 007603010103 seal

its a M10X1 thread fastened to 15Nm

Could it be that your corroded freeze plug is plug that has already been replaced by a non standard item? Folks tend to forget that 15 year old + cars may have had extensive repair work done already and some components may not be MB and possibly of inferior or unsuitable materials??

 

[Dieselman]

Before having the head skimmed check whether it is actually warped at all, it probably isn't.
Was the coolant leak the reason for changing the head gasket..I hope not..but the gasket does look in good condition.

 

[ps2cho]

which of these do you mean? http://www.detali.ru/cat/oem_mb2.as...GM=717.433&CT=M&cat=505&SID=01&SGR=065&SGN=07

There is a threaded plug to the oil gallery on the rear end of the cylinder head???

part no 000908010004 screw in plug

part no 007603010103 seal

its a M10X1 thread fastened to 15Nm

Could it be that your corroded freeze plug is plug that has already been replaced by a non standard item? Folks tend to forget that 15 year old + cars may have had extensive repair work done already and some components may not be MB and possibly of inferior or unsuitable materials??

It is on the Cylinder Block under Cylinder #6 at the back.

Before haviong the head skimmed check whether it is actually warped at all, it probably isn't.
Was the coolant leak the reason for changing the head gasket..I hope not..but the gasket does look in good condition.

Well we were told by at least 2 different Indy's that the head gasket was leaking and there has been hissing between two cylinders when we did a leakdown test (cyl 1+2)...but after looking at the head gasket it looks reasonably good as you said. Maybe it is leaking...maybe its not. Either way the engine just doesn't sound happy, my MPG sucks, I've been told my car feels about 40HP less than it should be...so its sluggish and I'm losing coolant from the back and oil somewhere else that we need to investigate.