Have 1984 300 d turbo 186k - experiencing slight coolant
seepage -
- acc/heat working but temp gauge not
ever going above 80c - even after 1hr at highway speeds
maybe thermostat needs replacing ?

any ideas appreciated!

I'd not expect the coolant temp to go over thermostat opening temp this time of year, even (maybe especially!) on the highway. The only time mine goes higher is in traffic in the summer with the AC on.

The thermostat is easy, though, so you could replace it very simply if you want, so long as none of the bolts is seized in the aluminum housing! Use anti-sieze on the bolts when you put them back in.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

is it coming out of the little holes on the water pump?? these are called "weep holes" and when you see coolant seeping from here, it is early warning sign of leaking internal shaft seal...time for new water pump.

Your coolant temp. is low...put in new thermostat...normal dash temp with new thermostat is 90-95C.

__________________
1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)

I thought there were different thermostats for different running temperatures: one for 80C and one for 90C, with the temperature stamped on the thermostat itself. If 84300D has the 80C thermostat then wouldn't it be fully open at 80C, keeping the operating temperature in that range?

In any case, a higher temperature gives a better combustion cycle, so you'd want to swap it out with the higher temp T-stat anyway.

- Nathan
'83 240D "Steiner"
'00 New Beetle TDI

[Edit: I may be incorrect; read MarkM's post regarding coolant temperatures.]

thanks MarkM + ncarter
- no coolant coming from water
pump which was replaced about 1.5 yrs ago -
coming from one of the hoses probably due to
contraction (since it's freezing down to 12 deg f
every nite here in CT !) however really not losing
much and everything tight after warmup.
not sure which temp tstat is in car now

suspect tstat maybe is the culprit - does anyone
try blocking off/restricting airflow through grille
like trucks to bring temp up in winter?

__________________
1984 300D Turbo - 231k....totalled 11/30/07 RIP

Rather than covering the rad, cover the oil cooler in very cold weather. This allows the oil to run hotter and do a better job of lubrication while keeping the coolant at the correct temp.

Do, however, remember to remove the cover is the early spring, as summer temps with the oil cooler covered will overheat the oil terribly, usually with ruined bearings as a result!

If you have a leaking coolant hose, replace them all -- it is leaking because the rubber is shot, and it will probably blow when it gets hot in the spring.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!