I found a head at a salvage yard/recycler about an hour and 20 minutes away.

Overall condition of the head appears to be nicer than mine, and included cam, injectors, etc. I looked it over but was focused on the underside of near the valves, and did not recognize anything to be alarmed about so I made the purchase and brought it home. I was kind of in a rush to get back home with it as I had to be to work in less than 2 hours.

Yesterday when I was cleaning the gasket material off the face I noticed that the large coolant passages near the outside of the head between cylinder 3 & 4, and the one between 4 & 5 were plugged with an orangish, hard scale.

I started poking at it and broke it free, then decided to look very closely at the area around the valves on cylinder 4.

I began cleaning with a wire brush on my Dremel, and found a little more pitting on this cylinder versus the others, so I removed the valves from that cylinder and found rust on the intake valve stem, up in the port,and the seat is pitted, and wet with what looks like coolant.

Next I wire wheeled around the valve on the face and I think I found a micro crack in about the 2:00 position, but I'm more concerned about the rust up in the port, and on the valve.

I called the recycler, and he said to go ahead and bring it back as he wants me to be happy with it and would refund my money.

A few minutes later he calls me back and says he had just received a call from a guy in GR that owns a 10 bay service shop that only does German cars looking for a part for a client. While he had him on the line he asked if these old Mercedes diesel heads were known for cracks in the heads.

Supposedly, the shop owner told him that every one that came in his shop had small cracks. It was just the way it is with these old MB heads. He said I would probably never find a head without some small cracks in it.

They weld the cast and in 20K miles they would come back cracked in the same place, through the welds.

The recycler even offered me the guy's name and number to talk to him myself.

I told him that I wasn't as concerned about the micro-crack I could see as I was about the scale completely plugging the coolant passage around #4, and the rust up in the intake port on that cylinder and the crack that I couldn't see. If I had recognized the scale in those ports while I was there I would have left it and not purchased it in the first place.

He accepted that and said to go ahead and bring it back.

BTW, I just wanted to mention that there was no evidence of scale in any other port on that head. None. Very clean in all respects.

Am I being too critical and cautious, or am I right in assuming there is a serious issue up in the intake port that can't be seen with the naked eye?

Will post the pics of this later, as I need to get this back to them by noon today. Gotta go.

Thanks.

Rick