1990 190E 2.6 headgasket

[04 Diesel]

Finally got the head off the 190E today, car has 205,000 miles on it. The car allways sounded like it was missing, I found out why. There is a piece of the exhaust valve on #3 cylinder that is broke off, you can see it in the picture. What would cause this?

[Adler]

Thermal shock may be reason of missing bit on valve .Was the piece still in the bore area and any damage ?
Do keep us posted with photos as you progress . Condition of seals and
guides ?

Regards
ad

[04 Diesel]

Originally Posted by Adler

Thermal shock may be reason of missing bit on valve .Was the piece still in the bore area and any damage ?
Do keep us posted with photos as you progress . Condition of seals and
guides ?

Regards
ad

I could not find the piece, the piston bore is fine. More to come.

[04 Diesel]

I have a spare 2.6 m103 with 140,000 miles in my garage, the motor that Im working on has 205,000. I was thinking about putting the head from the spare motor (140,000 miles) on the bottom half of the motor (205,000 miles) that is in the car now. What do you think? Or I also thought about just putting the spare motor in the car, I know nothing about the spare motor. The guy I bought it from told me it had 140,000 miles and it ran.

[ps2cho]

Unless you have any reason to do it, I wouldn't. We all know the bottom ends are near damn bulletproof. I would recommend you rebuild the head though. At 200k the guides + seals will be toast, your valves need to be replaced or lapped, and everything cleaned and skimmed.

Looks like a ton of carbon buildup on those pistons too -- get a dremel with a cleaning attachment and carefully get rid of that (TDC piston of course)

Whats that green crap too
Drain the block, flush everything and get Zerex G05 in there.

[04 Diesel]

Originally Posted by ps2cho

Unless you have any reason to do it, I wouldn't. We all know the bottom ends are near damn bulletproof. I would recommend you rebuild the head though. At 200k the guides + seals will be toast, your valves need to be replaced or lapped, and everything cleaned and skimmed.

Looks like a ton of carbon buildup on those pistons too -- get a dremel with a cleaning attachment and carefully get rid of that (TDC piston of course)

Whats that green crap too
Drain the block, flush everything and get Zerex G05 in there.

I was planing on rebuilding the head myself, I have the new valve seals, planning on checking the valve guides and lapping the valves. My son over heated the car so I guess I will take it to a shop and have them vacuum and pressure check it. I guess I will get a exhaust valve from my spare motor or buy one from someone on here. I didnt put the green crap in there my son bought it that way, all my Mercedes get G05. Thanks.

[04 Diesel]

If I would buy a used exhaust valve from someone, would I have to replace the valve seat or valve guide, or anything else?

[ps2cho]

You really wanna get all the guides replaced regardless for oil consumption reasons. The valve stem seals mask the oil consumption due to worn guides. The guides usually last 100k, but don't cause issues other than oil consumption anyway so new stem seals usually holds you over until the heads off.

I recommend you find a good machine shop (emphasis on good with experience /w older MB head's) and have them just do it all for you. Supply them the parts. I had my head skimmed, cleaned, pressure tested, valves lapped and guides + seals replaced for $215 (I supplied parts).

My guy did a great job:

[Hirnbeiss]

I suspect detonation from low octane gas at least contributing to the problem. The high carbon buildup suggests low-detergent gas also - I recommend Shell and Chevron.

[04 Diesel]

Made some progress today, valves are out and soaking in gas. Valve guides are fine, going to replace valve seals and clean valves and put all back together. Then going to the shop.

[04 Diesel]

Ready to go to the shop.

[04 Diesel]

I have a question for you guys, while I have the head off I noticed that the pully for the air pump is damaged. What does the air pump do, I also noticed that the metal line coming from the air pump looks cloged, is that soot? How do I clean that out?

[pawoSD]

Originally Posted by 04 Diesel

I have a question for you guys, while I have the head off I noticed that the pully for the air pump is damaged. What does the air pump do, I also noticed that the metal line coming from the air pump looks cloged, is that soot? How do I clean that out?

The air pump's original intention is to add extra air to the exhaust during startup. Its an emissions thing. I removed mine and put on a shorter belt.

[04 Diesel]

Originally Posted by ps2cho

You really wanna get all the guides replaced regardless for oil consumption reasons. The valve stem seals mask the oil consumption due to worn guides. The guides usually last 100k, but don't cause issues other than oil consumption anyway so new stem seals usually holds you over until the heads off.

I recommend you find a good machine shop (emphasis on good with experience /w older MB head's) and have them just do it all for you. Supply them the parts. I had my head skimmed, cleaned, pressure tested, valves lapped and guides + seals replaced for $215 (I supplied parts).

My guy did a great job:

How do you get the tops of the pistons that clean? I can get #1 and #6 but how do you clean the other tops without damaging the liners?

[04 Diesel]

Originally Posted by pawoSD

The air pump's original intention is to add extra air to the exhaust during startup. Its an emissions thing. I removed mine and put on a shorter belt.

What about the metal line that goes to the head? That metal line also goes all the way around the back of the block, cant see where it goes from there.