AH3000. Heating up

[Cooperman]

Hi. I have recently got my Healey 3000 mk1 on the road after a partial rebuild. When driving it seems to get quite hot. It runs the old original gauge and that seems to fluctuate around 190 deg when driving but when parked up and the engine is turned off the gauge rises to the max. When started again it does start to fall again. Is this usual?
I've only been running the car gently on a few short runs thus far to get used to it but it does seem to get quite hot. I.e. You can only touch the top hose momentarily before it will burn you.
Thanks Richard

 

[John Turney]

If you have a 190F thermostat, it will run at about 190F.

When you shut it off, cooling ability is diminished because there is no pumping of coolant nor a fan blowing air over the radiator. Hot water rises in comparison to colder water, so the hot water rises to the top of the cooling system where the thermostat is located. So the thermostat reads higher.

Healeys tend to run hot anyway.

 

[steveg]

...Healeys tend to run hot anyway.

In the UK I would wonder if there's a problem with the gauges.

I tested my gauge with an infra-red laser thermometer and two cooking thermometers. Removed the thermostat, started cold engine, inserted cooking thermometers and watched the temps compared to the gauge. My gauge was 20 degrees high according to the other thermometers. Therefore I removed the needle and repositioned it at the correct temperature.
My typical temps went down from 190s to 175+. This with my 180 degree sleeved thermostat.

These gauges can evidently get tweaked by overheating.

 

[Keoke]

HI:

In the UK I would suspect a cooling problem:
Bad Thermostat
Slipping fan belt
Partially blocked Radiator
Coolent passages in the block partially blocked-ETC

 

[Cooperman]

Hi. Took the car for another run this evening, approx 15 miles and sure enough it edged up to around 200. (And higher when not moving)
The top of the rad is extremely hot, can only just touch it, and the bottom stone cold... Literally!
it has new rad, pump, hoses thermostat, the lot. Any suggestions please.

 

[Keoke]

it has new rad, pump, hoses thermostat, the lot. Any suggestions please.

Move House-

 

[mwagon]

Did you check the timing & if fuel mixture is correct? Too lean could cause over heating

 

[steveg]

Suggest removing thermostat and seeing if situation changes.

 

[bdcvg]

X 2 on that , hot at the top and cool on the bottom means no coolant flow. Bad stat or blocked radiator.

 

[Michael Oritt]

i
Move House-

Even easier, tape over the face of the gauge and enjoy the ride. If you have a serious overheating problem it will evidence itself by radiator boiling over--otherwise your car simply runs hot as do many Healeys.

 

[Cooperman]

Thanks all for your contributions. It was a suspect stat. Changed it today and a steady 175 has resumed. Thanks again!

 

[DerekJ]

Just to be clear, a thermostat does not regulate the running temperature of the engine. It only controls the temperature at which water is allowed to flow through the radiator. It may be that the old thermostat was permanently closed or nearly closed thus reducing flow.