Tom's 300SDL with OM603 engine was leaking coolant and occasionally running warm , in time (3,200 miles from home) it became clear the cylinder head was bad so I began hunting for a replacement one .
These InLine 6 cylinder Diesel engines came with a defective cylinder head from new , few still have the original head , Tom's did and it failed although it lasted some 200,000 miles .
Step one : find a same year , same color , decent condition car for a donor , must have the latest and greatest version of the cylinder head on it . .
Finding one with the improved # 022 head already 1/2 removed was nice , this saved me serious labor .
The # 6 cylinder looked like it might have coolant leaks in it but the Machine Shop pressure tested it and said it's fine , they did a valve job and installed all new valve stem oil seals and new improved bucket typ cam followers sourced from The Mercedes Classic Center , transferred the cam from Tom's car as the new (used,#22 replacement improved) head had a bad camshaft and returned it to us , the car should be buttoned up and running this week .
Best of all , the $uper $pendy new head only co$t us $35 (
!) as the junkyard had not a care what it was , just another 28 year old Mercedes wreck

.
After the valve job , gaskets and so on , it will not have been a inexpen$ive repair but less than 1/3 the price of having a shop find us a good used head ~ the cheapest used head I'd been able to find was still $700 + freight , only warrantied to be crack free , not a fresh valve job nor the all important valve stem oil seals , they prevent exhaust smoking .
Meanwhilst Tom's old '81 300SD has been pressed back into daily service .
-Nate