revelation about "only clicks when starting hot engine" problem
 

I've seen several posts over the past few months discussing problems with starting a HOT 617 engine. In all cases the common issue was that the user reported the starter solenoid clicked but the starter motor did not turn over.

Well, on my road trip across the snowy Rocky Mountains I figured out what my issue was, as I've had the same problem. It's me, not the car.

In my case I was being too impatient in trying to immediately start a hot engine and not waiting for the glow cycle to complete. From time to time it's clear that there is insufficient power for the battery to power the glow plugs and turn the engine over at the same time. Wait for the glow cycle to complete and my "intermittent hot start problem" went away!

Hopefully this will help some other members reporting the same problem.

Sounds like a bad battery or alternator to me.

No, the glow plugs are de-energized when you release the key from the starting position. The FSM says "If the key is turned to position "3" (start), the power relay (a) remains retracted, activated by terminal 50. The glowing process is continued until the key is returned to position "2". [Source: Service Manual, Diesel Engines 602, 603 by Mercedes-Benz of North America, 1990.]

Caveat: some earlier Mercedes diesel engines may have a different pre-glow relay that does not work in that manner.

Unfortunately, this puts me in the position of disagreeing with Toronto's statement. If the car has recently been driven (and therefore has a "hot" engine), it should have a fully charged battery. So there should not be a problem unless the battery is old/weak. Therefore, I am puzzled by what is causing a hard-starting problem that is fixed by waiting a few seconds after turning the key to position "2."

Jeremy

Energize???:D

Well I'm puzzled too.

The alternator is new and the battery is good - started the car in low temps several times on a trip last week across the Rockies from Calgary to BC. Turned over like a champ in -11C temperature after sitting in a lot in Calgary for a week.

All I can tell you is that if I let the glow cycle complete she turns over perfectly.

If I rush it when the engine is warm, it fails to turn over once every 10 or so starts - just get the solenoid click.

I am no expert but I have had lots of engines in lots of equipment. Whether it was diesel or gas in a truck car or boat. A poor starting engine hot as always been the starter just my few cents

I agree. But, also clean/check all electrical connections in the starting circuit.