350SDL Engine Question
Robert Condon
engine was put in by a Mercedes dealer and it now has 32K on the engine.
After I bought it, I learned that the 350SDL engine model had significant
problems. Does anyone know if a replacement engine put in in '97 would be
subject to the same problems -- or did Mercedes fix this engine by then?
In either case I suspect I am lucky to have purchased one with a relatively
new engine -- or am I? The part number on the work order for the engine is
603-010-69-00-88 if that makes a difference.
Thanks
David C. Allen
Contact Gary Corley <cor...@texoma.net>, they are doing some checking
into the 3.5 liter turbo diesel
David
W140 Web Page:
http://www.primenet.com/~davida/140start.html
VCopelan
>I just purchased a 1990 350SDL with 150K miles on the body. In 1997 a new
>engine was put in by a Mercedes dealer and it now has 32K on the engine.
>
>After I bought it, I learned that the 350SDL engine model had significant
>problems. Does anyone know if a replacement engine put in in '97 would be
>subject to the same problems -- or did Mercedes fix this engine by then?
>
>In either case I suspect I am lucky to have purchased one with a relatively
>new engine -- or am I? The part number on the work order for the engine is
>603-010-69-00-88 if that makes a difference.
From what I understand, all the 603 type diesel engines have lots of problems.
The first generation 603 engines in the 300SDL and 300TD had cylinder head
cracking problems (reportedly the head has since been redesigned). These
engines also have lighter head bolts, smaller oil filters, thinner injector
lines (which often break) than the earlier 5 cylinder diesels. In addition
these engines don't have the separate cam bearings like the early 4 and 5
cylinder diesels and they have one piece Aluminum oil pans (don't hit any
rocks). Apparently, the later 3.5 liter 603 engines have even more problems
with reports of ovalized cylinders and bent connecting rods (I suspect the 3.5
liter 603 engine uses lighter connecting rods). Personally would not drive a
3.5 603 engine to high mileage but you might get lucky and not have problems.
If you can still sell the car for a good price, consider another Mercedes.
Marshall Booth
etc.) in the "new/rebuilt" engines they have installed to replace the failed
OM603.97xs. Whether these changes will prevent premature failure of these
engines is open to question since it is not entirely clear what the root
cause of the original failures is/was (it's been widely argued, but not
proven, that it's an inappropriate bore/stroke ratio). It has also been
suggested that low "quality" US diesel fuel is the "cause" of the problem
(MB has insisted the premature OM603.97x engine "failures" are confined to
engines imported to the US - but further insists that there is NO defect in
the engine design). This fits with the fact that European #2 diesel is
typically 50 or higher cetane, while US #2 is largely 40 cetane with minimal
quantities of 45 and 50 cetane fuel available at premium prices in a few
locales. There is an anecdotal report of a US delivered 3.5 liter engine
that has been run on NOTHING but 50+ cetane fuel reliably running more than
250kmi (the highest mileage 3.5 liter engine I know of) without evidence of
impending failure. I know of NO failure of replacement engines so far, but
most of these have less than 50kmi on them (that about when the original
engines started to fail, though most of the failures were at closer to
100kmi).
Marshall
--
August M. Booth, Jr. Ph.D.
Univ. of Pittsburgh School of Medicine
"der Dieseling Doktor" mbo...@pitt.edu
'87 300TD 139Kmi,'87 190D 2.5 189Kmi, '84 190D 2.2 233Kmi TERMINAL,
'84 190D 2.2 210Kmi, '85 190D 2.0 144Kmi, '87 190D 2.5 turbo 200+kmi
MBCA, GWSection
http://www.dhc.net/~pmhack/mercedes/mbooth1.htm
VCopelan
>MB has made a lot of changes (rods, pistons, cylinder liners, oil system,
>etc.) in the "new/rebuilt" engines they have installed to replace the failed
>OM603.97xs. Whether these changes will prevent premature failure of these
>engines is open to question since it is not entirely clear what the root
>cause of the original failures is/was (it's been widely argued, but not proven
that it's an inappropriate bore/stroke ratio).
How do you "change" cylinder liners on a 603 Mercedes diesel engine to prevent
premature failures? I can understand changes to the connecting rods. And...
I guess it's possible that Mahle didn't know how to make pistons for the 603
engine (unlikely but all things are possible). However, what possible changes
could Mercedes make to a cylinder liner? Just wondering.....
rfburnz
"Marshall Booth" <amb...@email.msn.com> wrote:
> it is not entirely clear what the
root > cause of the original failures is/was (it's been widely argued,
Mechanics (more than one) I spoke with say the vacuum pumps in early 6
cyl diesels were of an inferior design, they self destruct and bits of
metal lodge in the oil passages, etc. Why would MB replace or repair
engines at their cost if they thought the problem was due to low cetane
American fuel?
Reid
Three diesels and counting (all W123)
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Before you buy.