O.K. I replaced the waterpump but I didn't change the thermo. So now for some reason the thermo is sticking and overheating the engine. What interests me in this is that the pump I took out had exposed fins (no flat disk) in the pump vortex area whereas the jobber pump I put in had the usual looking flat disk that I presume is in front of the fins. None the less the thermo eventually opens and the temp goes back to normal.
So was my old pump a higher output design that was masking a failing thermo? Or am I just a cheap bastard who saved a few pennies when he had a perfect opportunity to change the thermo in a well lit heated garage and who is now going to pay for his miserly behavior by changing a thermo in a windchill of -40?

I agree with egs60racer.

1. Check all components of cooling system. Replace suspect elements as necessary. Test thermo or replace (cheap part).
2. Flush radiator and clean radiator and AC condenser fins.
3. Check wiring and possibly the compensating board in the instrument cluster. Your engine may not be overheating after all.
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1987 - 240 DL 76k mi

your thermostat and do try to do it in a little place :-)

Good luck,
SM
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90 BMW 325is, 98 BMW 528i, 90 Volvo 240DL

Actually that depends, what do you mean by bleed?

This may be a silly question as you just had the system open and presumably put in new coolant, but how's your anti-freeze ratio?
Slush in the system might look like a frozen thermostat.
Joe

This is going to be a dumb reply, but I replaced everything on my DL trying to figure out why it was overheating, turns out, the ground strap to the motor was off and it was tripping out the gauge. Go fig

Doug
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Sacramento VCOA President, (sacvolvo@hotmail.com) Admin @ clubvolvo.com 2001 S60 2.4t w/17' Amalthea & Premium package 82 242t 5spd (Offical Project Car!) w/ With more parts than I can list, 85 244ti~ Parts car