C280 Head Gasket R&R
 

I have to replace the head gasket on my 1994 C280. Can anyone tell me what other areas should be addressed while it is apart? Also are any special tools needed?

Ah the infamous M104 head gasket rears it's ugly face again !!!

Since you're going to go through the trouble of removing the head to replace the gasket, by all means, spend a couple hundred dollars more and have the head sent out and checked for straightness and honed, new valve guides and valve seals.

Also, when the car is put back together, have new resistor boots installed for your 3 coil wires. They are about $10 each. Your coil wires are made of solid copper and are very likely still good.

Do you know if your engine wiring harness has been replaced?

If not, symptoms of a bad harness might rear its ugly head. The harness has to be moved aside when the head is removed, and because of that insulation flakes off the wires.

Engine wiring harnesses from 93 to 95 were bad, so if yours is original, you may have to replace it. Cost? $500.

While the head is off I'd be tempted to throw a new timing chain and tensioner in too, but not required if the chain is in spec. Just might be a good time to do it budget allowing...

I wouldn't waste my money grinding the seets and replacing the guides. It's more than just a few hundred $ on the 104s. every gasket i've done with even up to 150k on it the valves themselves and the seets look perfect. just my 2 cents.
paul

If you are replacing a head gasket, and you don't want to get into replacing valve guides and grinding valves what type of head work is prudent to do to? I would assume that you would clean the carbon off the combustion chambers and clean the piston heads. Would it also be wise to clean the carbon off of the valves and maybe lap them in again?

Wouldn't it be foolish to at least not replace the valve guides?

The valve seals can be replaced with the head on the engine, but the head has to be removed for valve guide replacement.

Agreed ....

This head design has minimal vave stem/quide side force [ cam-valve swipe] . They seem to have solved the common 103 guide problems with this far superior design and it is not unusual to see them still tight into the 200K figures.
The 104s have a very strong top end....along with some pretty good breath....

The problem was the Gasket, not the Head....

O.K. I'll buy that. Thanks Arthur. In fact, I think you explained that concept to me over dinner at your restaurant in Milford, NH.

Paul,
I remember talking about it with someone, so now I remember
it being part of our meeting here in NH.
Good Time...

Jetforman is up this way visiting, so we may do the same ..
[ You don't want to be here now... it is a BAD winter ]
...unless you are a Skier....I'm not cuz the only time I want something that long for leverage is when I put a pipe on a breaker bar ...not my Ankle !!!!!
I am out of here for Ocala in a couple of weeks and won't be back til spring.. can't wait....

See ya
Arthur