Yup. Starting in the late 60's, Benz took over design and production
of their cylinder heads from the company they had been buying them
from. It seems they were quite rude about it, and the original design
stayed with the original company, and cooperation was, well, mostly
non-existant.
The result was very short lifetime -- severe cracking problems,
particularly on the small diesels. It got to the point that my friend
Hans said his father wouldn't buy one with less than 20,000 miles on
it, on the theory that if it was still running, it was a good one and
would go quite a while more. Hans eventually recommended that they use
something else for their taxis until Benz got the problem solved.
There are at least four head designs installed on the 615, and not all
heads are compatible with all blocks, and I believe there are several
head gaskets as well.
Eventually, they became quite reliable.
Peter
