It is my 81 240
After a drive that got the temp. up to 82*, I shut off the car, ran a quick errand of 1 minute and returned to the car.
When I switched back on, the temp was up near 100.
As soon as I got moving ther temp returned to 82.
Is this a normal situation?
For the past year, after a rad change, new hoses, tstat and coolant, the car would run near 90 and quickly rise to 100 when climbing or hard running for a while.
Forum members opined trapped air as a possible reason.
I have done no cooling system work since last years work so if it was trapped air, it was not purged by me.
Last month, I finally bled my slave cyl, after over a year of soft pedal and grindy reverse and got my clutch back and simultaneously my 90-100* running was gone replaced by the current 82*.
Is this just coincidence or was the unbled slave causing clutch slippage and thus overheating under load?
What say youse?

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1981 240D 143k 4 spd manual -SOLD

2004 VW Jetta TDI 5 speed 300k -still driven daily

Does the circulation of coolant stop when the engine is shut down?

I assume such, so you are saying it is normal?

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1981 240D 143k 4 spd manual -SOLD

2004 VW Jetta TDI 5 speed 300k -still driven daily

Yes

My car does this. No need to worry unless the engine exceeds 120* C, which I doubt will happen.

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-Typos courtesy of my mobile phone.

Before my radiator started to go (last year) this would happen. It has not happened since the new rad.

I had a very fine crack on the top tank. It was very difficult to see and rarely leaked enough to see it. The coolant level never really dropped a substantial amount either.

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AJ

1985 300D (SOLD)

You know, I noticed a bit of coolant at the very top of the radiator near the hose that connects to the coolant tank. I check my engine bay very often (once a week ocd ) and it comes and goes. It isn't big at all, but just enough for the area to be moist. Tightening the hose doesn't seem to do anything.

Coolant level hasn't changed at all.

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-Typos courtesy of my mobile phone.

It's just heat soak is all

Yup, mine do it too. It's not a problem.

It's normal. The engine is cooled via the coolant in the radiator and the water pump pumping coolant through the system. So if there is no air flow through the radiator, and the engine is not running the hot engine will heat up the water instead of the in flowing cool water cooling the engine.

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the moist spot at the little hose to the reservoir means the nipple has a crack in it or the hose is dry rotten. replace the hose if its old, careful w/ that stupid little nipple, very fragile and prone to break off. mickey mouse fix is jb weld, otherwise replace radiator.

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1984 300TD "MAX" 303K+ still going...
fast '70 Chevelle 200k+
home built Shovelhead chopper

It's perfectly normal, but for a literal one minute errand I think Id've left the car idling. Shutdown/startup is one more cycle on the starter/battery life and for just a minute, it's not going to hurt anything even if you are in the *just because people have left diesels idling for fifty years doesn't make it a good idea* group.

My $0.02. Either way, one more vote for the heat soak being normal.

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~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

Heat soak is normal. Some turbo motors have a shut down timer to save it from over heating. If you take any car for a good hard run on a very hot day & then shut it off without a time at idle it generally boils in the top of the motor & radiator.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

Turbo timers are meant to cool the turbo down from white hot to something less, before oil stops flowing through it. If you are the kind of person who pulls off the highway from having just passed a bunch of traffic, for a pit stop, and turn the car off immediately when coming to a halt - you'd benefit from a turbo timer. It's nothing to do with coolant overheating, or the rest of the engine for that matter. It's more about keeping oil moving around the turbo bearing.

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Cheers!
Scott McPhee

1987 300D

It is approved after hard running to allow the block temperature to equalize before shutting down. Eliminates hot spot warpage. Actually recomended by most old time diesel mechanics.

Certainly harms nothing in my opinion and perhaps extends engine life.

As Barry 123400 alludes to: Another benefit of a "turbo timer" is allowing the coolant temperatures to stabilize throughout the engine - which can potentially extend the service life of the head gasket on engines with dis-similar metals, i.e., iron block & aluminum head (which obviously have different thermal expansion rates). In theory...

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Current rolling stock:
2001 E55 183,000+ Newest member of the fleet.
2002 E320 83,000 - The "cream-puff"!
1992 500E 217,000+
1995 E300D 412,000+
1998 E300D 155,000+
2001 E320 227,000+
2001 E320 Wagon, 177,000+

Prior MBZ’s:
1952 220 Cab A
1966 300SE
1971 280SE
1973 350SLC (euro)
1980 450SLC
1980 450SLC (#2)
1978 450SLC 5.0
1984 300D ~243,000 & fondly remembered
1993 500E - sorely missed.
1975 VW Scirocco w/ slightly de-tuned Super-Vee engine - Sold after 30+ years.