Running Cold

[Novamonte]

I just took my Tricarb for the first spin for the season. We have enjoyed a great, quite warm day for the season (7C/45F) and the car ran just fine! The previous owner used a rather light, straight oil (SAE20 - 30, the marking is a bit unclear) so the oil pressure used to be on the low side when the engine warmed up. I have changed to Castrol Classic 20W50 and now it stays around 40 which seems fine.

I noted that the temperature was a bit low (160F/71C). It usually hits the 180 mark. I guess it is because the low ambient temperature. What would you experienced owners say? Is 160F normal when it is a bit on the cold side outside? The -66 Mercedes I used to have always hit 80C/178F even when it eas cold outside, but that may not apply to Healeys...

 

[John Turney]

...I noted that the temperature was a bit low (160F/71C). It usually hits the 180 mark. I guess it is because the low ambient temperature. What would you experienced owners say? Is 160F normal when it is a bit on the cold side outside? The -66 Mercedes I used to have always hit 80C/178F even when it eas cold outside, but that may not apply to Healeys...

That's about what I'm seeing at that ambient temperature.

 

[dcarlg]

What is your thermostat rating?
Perhaps 160F?

 

[Novamonte]

That may of course be the case. I have owned the car for less than a year and have not had the thermostat out, so I am not sure. I have always assumed that it was rated at 180F since that was the normal running temperature during summer, but that may of course be because the radiator is unable to keep the temperature below 180F in warm weather even with a fully open thermostat. Last year we had an exceptionally hot summer for being in this part of the world with temperatures rarely falling below 30C/85F.

 

[Michael Oritt]

What you are describing is normal assuming you now have a 160 degree thermostat.
If you would like your minimum running temperature to be 180 degrees then simply install a 180 degree thermostat.

 

[Rob Glasgow]

I have a 195 degree T-stat in my BT7 and it runs between 165 and 175 when the ambient temp is 60 to 70. I have tested the t- stat and it opens and closes about 195 so it appears to be working.

 

[steveg]

It's easy to remove the thermostat from the car and check its opening temp on the stove with a cooking thermometer.

 

[Novamonte]

I have a 195 degree T-stat in my BT7 and it runs between 165 and 175 when the ambient temp is 60 to 70. I have tested the t- stat and it opens and closes about 195 so it appears to be working.

A bit odd though that the engine won't reach the opening temperature of the thermostat. I would think it should since the water should normally not pass through the radiator until the thermostat opens? I guess this can be the case where there is a sleeved thermostat, allowing some coolant to circulate through the radiator even before the thermostat opens.

Back in the day it used to be quite common here in a colder climate to change thermostat according to season, a "winter" thermostat allowing higher temperature and a "summer" thermostat opening earlier. Many would also put a screen on the grill in the winter to reduce the amount of cool air passing through the radiator. Old Volvos (and perhaps other cars as well) even came from the factory with a curtain behind the radiator that could be operated from behind the wheel.

I am considering changing the thermostat to a 180 degree because running at 160 seems to be on the low side. Any thoughts in the ideal temperature for the Healey?

 

[Bob_Spidell]

Mechanics and engineers say 190degF is the ideal operating temperature (though newer cars may run a bit hotter; who knows, most don't have an actual temperature gauge). Healeys will run at whatever temperature they please (including cooler than the thermostat set point for reasons nobody knows). Both my BN2 and BJ8 will run below their 180degF thermostats on cool/cold days (I've tried several and 'bench checked' them).

 

[steveg]

Mechanics and engineers say 190degF is the ideal operating temperature (though newer cars may run a bit hotter; who knows, most don't have an actual temperature gauge). Healeys will run at whatever temperature they please (including cooler than the thermostat set point for reasons nobody knows). Both my BN2 and BJ8 will run below their 180degF thermostats on cool/cold days (I've tried several and 'bench checked' them).

I've got a verified 180 thermostat and my car runs at around 160 - 170 on cool days.

It would be interesting to hear from someone who's running without a heater.

 

[Deleted member 21878]

Steve/ Bob
Do you run an oil temp gauge as well?
also does your upper hose get hot even if the gauge is saying 160? in other words does you thermostat open?

i wondered if the gauges were influenced by the cast iron bowl they set in out in front of the engine???

i was thinking of trying a test on mine. one day when it is 60 out, taking a ride, say 20 miles. then when i get back, before i shut it off, take some readings off the engine with the IR gun. oil pan, top hose, the bowl, bottom hose... just a few randon spots. then one day this summer when it is 80, do the exact same test and see if the other readings vary as much as the gauge.

 

[Bob_Spidell]

Steve/ Bob
Do you run an oil temp gauge as well?
also does your upper hose get hot even if the gauge is saying 160? in other words does you thermostat open?

i wondered if the gauges were influenced by the cast iron bowl they set in out in front of the engine???

i was thinking of trying a test on mine. one day when it is 60 out, taking a ride, say 20 miles. then when i get back, before i shut it off, take some readings off the engine with the IR gun. oil pan, top hose, the bowl, bottom hose... just a few randon spots. then one day this summer when it is 80, do the exact same test and see if the other readings vary as much as the gauge.

No oil temp gauge for me (my new Mustang doesn't have one either, which I feel is a 'defect;' but it does have a vacuum gauge layful.

That sounds like a solid plan; I may buy an IR temp gauge and try it myself. But, my hunch is the engine just runs cool on cool days, which might not be surprising with a light aluminum block engine, but seems counter-intuitive on a big iron lump.

 

[steveg]

I've had 2 Smiths oil temp gauges from UK suppliers (sucked in by the low exchange rate): a mechanical one that quit after a few months, then an electronic one that read wildly high. I've been experimenting with adding resistors in series with the sender to get the normal running down to near what my HF IR thermo reads adjacent to the sender. Not very satisfactory, but one is stuck if ordering from the UK due to the cost of shipping it back.

The takeaway here, IMO, is that if one wants one of these gauges, buy it from a US supplier such as Nisonger so you can return it if necessary.