There are more photos at photos.yahoo.com/tabijan in the 91 300SE other head and manifold shots album.

I'm curious about the varying surface textures and colors of the coatings on the exhaust valves. I'm particularly curious about the loose carbon-like scale in the #6 combustion chamber. It flakes right off.

A local indy serviced the car before I got it in June 2000. The green stuff that was in there wasn't so green anymore as you can see from the residue in the coolant passages. Is this what green stuff turns to over 3 years and 25K miles? No wonder I'm changing a head gasket.

Greg in Oz, pulling the head with manifolds wasn't so difficult. In retrospect, maybe I could have left the manifolds in the car. The only really difficult job would have been detaching the EGR pipe from the bottom of the intake manifold. There isn't room for a big enough wrench between the intake manifold and the crossmember.

Sixto
91 300SE
87 300SDL
83 300SD

Leaving the intake in place is the way to go on the 103.

It is not uncommon when antifreeze is not kept changed for corrosion at #6 to eat right through. If it has, you can find a shop that can weld it up with no trouble.

When the head is off, don't even think about putting it back together without new valve guides.

Good luck,

As Larry suggests, the M103 is fussy about coolant quality. When I pulled the head off ours the gasket was badly corroded and was allowing oil from the oil feed at the rear corner into the water jacket. Fortunately nothing else was corroded. Maybe the gasket works as a sacrificial anode. In your case it appears you may have been getting coolant into #6 cylinder. The problems often occur back at this end, initially with oil leaking from the rear corner.

I can see what you meant with the EGR pipe, our Oz delivery does not have EGR so it was easy to pull the head and leave the inlet manifold in the car. Unlike you, I only removed the rocker shaft and camshaft and left the rest for the shop that did the head for me. They removed the valves, cleaned everything, crack tested the head and skimmed it to ensure it was flat. They then reassembled it with new stem seals but claimed it did not need guides (140,000km approx.). When I got it back everything looked like new. All this including the VRS gasket set cost me less than $400 AUD. Three years on now at 175,000km it is still perfect. Not a single leak nor any oil consumption.

Good luck with the rest of your overhaul.

__________________
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.

FWIW I pulled the cam before pulling the head because I didn't want to risk clipping an open valve in case I had to 're-lower' the head because something was hanging.

Sixto
91 300SE
87 300SDL
83 300SD

Speaking of the camshaft, what opinion do others have as to when it should be torqued down, before the head is refitted or after? Discussing this with others, I did it after the head bolts were torqued. The idea being that if the camshaft was torqued down first then the head bolts were torqued, it could stress the camshaft. Torquing the camshaft down after the head bolts have not caused me any problems. What opinions do you guys have?

__________________
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.