jmwathen

The problem is it will not start it will crank but won't start. It has been sitting for a while (appr. 2 yrs,) I do not know much about diesel engine but have done alot on gasoline engine. Thought someone might have a answer. The person that has it for sale say's it has blown head gasket would cause it not to start???

TMAllison

Start with teh basics first; check GP's and relay with a multi meter (see dieselgiant.com W123 tutorial), crack IP fuel lines one at a time while cranking until fuel leaks from each to confirm its primed and then check comp.

You can spray a continous stream of WD40 in the intake while cranking if it seems like it wants to start but won't. No ether...!!

If it still won't start you may have to pull tthe head to determine if it is the gasket or the head that cracked.

jmwathen

I will try it!!!

beeman

If anybody out there can supply me with the MB part number for the adapter that screws into the pre chamber to remove with slide hammer I would greatly appreciate it. Thanks.

TMAllison

What was the compression? Knowing compression will tell you if that cyl is capable of firing. If indeed the comp is low, a leak down test will help determine if it is valves, gasket, rings, etc., etc.

Unless you can hear the ball on the end of the PC bouncing around inside that cyl like a marble then pulling the PC is going to be a waste of time.

See page 56 for the PC tools....... http://www.peachparts.com/diy/mb_too...ls.php?page=56

beeman

I will do a leakdown test first but I would still like the tool just the same. Peach Parts doesn't regretably ship outside of the US and I am looking for an MB number. The local MB parts man will not do this but will order in the tool if I can come up with the number.

TMAllison

Email Phil and tell him your issue. He'll prob be able to read it off to you.

beeman

Hi TMA, and thanks for the reply. I do not have Phil's Email address.

TMAllison

Bottom of page I linked. Tell him your problem, and ask if he can assist.

Say one of the guys from "mercedes shop forum" told you to "call".

beeman

Thanks I now have the number.

beeman

And then the line went dead. I am ordering a leakdown tester from Zdmak and I will test further before taking anything else apart. I am determined to find out why #5 cylinder won't fire. I will post when I have something to report meanwhile my '85 300sd runs fine and I am parting out an 85 300sd. Thanks for your support TMA.

beeman

I have taken a leakdown test on missing 5 cylinder to discover a leaking valve. Valve adjustment was correct and so the valve is the problem, intake as you can hear the leak at the intake maniflold. Thanks TMAllison for your advice. My 85 300sd runs fine hopefully I can peal off the bad head at my leisure and go from there. I will do a leakdown test on all pots first. My head machine shop man wonders if I should automatically change all head bolts. Would that be the right thing to do?

TMAllison

Making progress.

The head bolts are designed to stretch. They can be reused if still within tolerance. I don't know the spec.

You need a triple sq bit. Dont try removing them with a trox bit, they'll strip.

beeman

Thanks for the advice as I intend to do the head if the leak down test on all other cylinders are alright at least and take it from there. One more thing, is the engine in my 80 300 sd the 'same' as that in the 82 300sd? Some of the vacuum plumbing is different etc.