blown head gasket........again! - Page 2 - PeachParts Mercedes-Benz Forum

whunter · #16 02-04-2014, 04:56 PM

Quote:

Originally Posted by Rooster300SD

I pulled the head and took it to the shop.
No cracks but it is 4 thousands out of spec for flatness.
They are going to fix that and redo one of the valves.

Once I pulled the manifold, I could see there was oil & coolant leaking from
the HG. I'm going to clean out all the bolt holes with a tap before installing
the new bolts. I'm using a calibrated torque wrench borrowed from my neighbor who's a retired mechanic.

I'm going to surgically clean those mating surfaces.
Hopefully, this will be the last time for this head!!

Thanks for all the advice.

Jeff

I sincerely hope this is the last time..

.

dieseldiehard · #17 02-04-2014, 09:33 PM

Sorry to hear of your problem. I might have missed it but did any one ask what type of gasket you used? I was told Victor Reinz is the best and that's what I've always used. And be sure to back fill the head with coolant first time you fire it up you don't want any bubbles in it, Search burp the engine for a lot of discussion on that. There is also a vacuum backfill kit made by MityVac but simply adding water into the head thru the heater hose, not just thru the reservoir is easy and effective.

Trying to remember how I cleaned out the bolt holes when I installed a rebuilt head on my '87 300D but I had a long brush I think I found it in a hardware store, probably made for some household chore but it was about 3/8 in across the nylon bristles, it was a tight fit. I used some solvent and rotated the brush out like a screw.
Following that I inserted a long thin air tube and blew out the holes from the bottom up. You'll probably see lots of stuff will emerge.
I would be careful if using a tap not to take out any metal as the torque process might be modified (less metal). I did use some 30W oil as I recall on the bolts, do not fill the holes, you can't compress that stuff!

I did the work under the wing of an old European mechanic and he refused to reuse stretch bolts and FWIW its held up for 6 maybe 7 years now and is still running great except another Glow Plug failed recently. Damned thing is I have an '85 OM617 turbo engine in my '79 300TD with parallel glow plugs fed by the original GP timer and those plugs have been good for over 20 years now, I just checked them and I expecting at least one of them to have opened up but they are still AOK! and that car has about 110K miles on it since the GPS were installed at a major rebuild. Quite a lot of time for those glow plugs don't you think? so why has the '87 had three GPs fail in a fraction of the time? and I have not made the GP afterglow mod to it either. Oh well as they say YMMV.
DDH

Quote:

Originally Posted by Rooster300SD

I pulled the head and took it to the shop.
No cracks but it is 4 thousands out of spec for flatness.
They are going to fix that and redo one of the valves.

Once I pulled the manifold, I could see there was oil & coolant leaking from
the HG. I'm going to clean out all the bolt holes with a tap before installing
the new bolts. I'm using a calibrated torque wrench borrowed from my neighbor who's a retired mechanic.

I'm going to surgically clean those mating surfaces.
Hopefully, this will be the last time for this head!!

Thanks for all the advice.

Jeff