My diesel starts first time when cold (immediately).
When hot it will start immediately if switched off and then back on right away.
If left for a few minutes it needs to be cranked over many many times before starting, usually I have to switch off at least twice between repeated cranking over of the engine (very frustrating).
I have also noticed since this problem started that the engine tends to run on a little after switch off (maybe my imagination).
I changed both fuel filters and the problem persists.
After the engine cools down for approx 30 minutes it will start immediatly again.
The station wagon has run for 250K miles and is still in nice shape, I love it except for this problem.
I would appreciate if anyone has any suggestion as to what the problem may be.

TonyR,

This is not a sympton of plugged fuel filters as you found out.
Symptom of plugged filters is loss of power when engine is under a heavy load such as going up a steep hill
.
I would look it as a GP problem. Are the GP coming on when the hard start problem is present? Are you waiting long enough for the GP to heat? Don't rely on the dash GP light. It can be out of calibration like one of mine and cause you to try to start the engine too soon.

Try waiting about 30 seconds for the GP to heat and see what happens.

P E H

Tony R.,

Did things work out? This seems to be a common problem, actually, and if the issue could be nailed down a little bit with a definite series of steps to fix it, a lot of W123 Diesel owners would benefit. Jim

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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Tony
Pull off the vac pipe from the shut-off diaphragm (arrowed in the attached image), look for signs of oil and see if it will start immediately disconnected.
If so:
1) Turn ign. Switch on to # 2 position.
2) Use an aerosol can of penetrating fluid to blow thro the vac line to the switch and wash out the oil and then turn the can upside down to blow out the fluid. (You will need to remove the dash panel under steering column and wrap a rag around the switch to catch the mess – no need to pull the pipes off.) This is a common problem with these engines.

If no start we will need to look elsewhere:-). Let’s know how you get on.

Don't know what happenned to my original post, I edited it but must have deleted it accidently!!
Beagle

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Beagle