Running Hot

[chesterx]

I have a P23 with a 180 degree thermostat installed-brand new. Car runs hot, especially up a hill. I have replaced water pump- new, and flushed system. Verified operation of the thermostat. I was gearing up to replace the water distribution tube when I noticed that my manifold heat riser was sticking a little. Lubed it up but it seems to need a little help in moving and after reading many articles on the subject I am really confused as to what position the heat riser assembly should be in (cold and hot)???? Would this cause the car to run hot??? Any thoughts as to which way to go on this would be greatly appreciated. By the way compression is A-OK in all cylinders.

[greg g]

Rotated clockwise closes the heat riser. That is the flap wil be in aposition to NOT Direct exhaust gas into the intake heat chamber. the at rest position is the open position, the bimetalic spring shoud turn it clockwise against the counter weight when the engine is up to temp. A stuck heat riser may cause higher under hood temps as there are two cast iron masses exposed to exhaust gas temperature, but is shouldn't have much of an effect on engine colant temp. Have you checked the actual temp of the coolant with a reliable thermometer? A small cooking thermometer stuck into the radiator fill will indicate colat temp. This will be slightly cooler than the sensor temp as it is pretty close to where the coolant flow is the hottest. but your gauge may be off. Have you checked your radiator flow? High temp speed usually indicated a coolant flow situation, is your stat opeing all the way? What happens when you run with out a stat?

[chesterx]

Good ideas, i'll get on them this afternoon and let you know, Thanks

[chesterx]

Some temperatures taken with an IR thermometer after a 10 mile drive:

Top of head: 210F working back to rear which was 218F at very rear

Exhaust manifold ports were running at 345F

Exhaust manifold junction was at 465

Block temps were all 208F

Water outlet was right at 180F

Maybe its not running that hot! Temp gauge sits on the halfway mark.?????

I was able to repair the manifold heat riser with lots of penetrating oil.

[chesterx]

Thanks All,

After fixing the manifold heat riser and installing a new $15 guage the engine never got over 190F