thermostat for summer use

[martinjohn]

Any one know what the thermostat rating is for a 1969 tr6 for general summer use. Just took the old one out and its rated for 74 degrees, i have another on the shelf rated as 82 degrees, any recommendations please.

Regards

[RAHTR4]

Hi Martin,

 

The period AC catalogue states 82 degrees for Summer use and 88 degrees for Winter.

 

Regards, Richard

[martinjohn]

Thanks Richard

I think i will put the 82 degree thermostat back in place,theoretically the engine should run just that little bit hotter.

Regards

Martin

[Andy Moltu]

74 for hot climates/summer

82 standard

88 cold climates/winter

 

I wouldn't go for a 74 in the UK at all.

The 88 makes a difference to the heater output.

 

Always struck me as odd to have different temperature stats for the same engine. The engine should have an optimum operating temp which you might think should be relatively independent of the outside temperature. (I acknowledge mixtures may need varying at different temperatures and pressures - as modern cars efi systems do, but not convinced the coolant temp would)

 

The thermostat isn't the rate limiting factor in terms of whether the car overheats or not. A fully open 74 degree stat should allow as much coolant to flow as a fully open 88 degree one (assuming the thermostat isn't faulty)

 

Granted in the UK we have produced cars with marginal cooling capacity that works ok over here but when put into a genuinely hot climate hasn't got the coolant flow, airflow or radiator size to dissipate the heat.

[boxofbits]

I used an 82 degree stat for the IWE weekend, and a couple of times the guage stabilized at around 1/4" off the red sector in standing traffic, i.e The bx@#y Dartford Tunnel with an 8 mile queue! I have checked the temp with a digital temp meter and know the stat is regulating correctly. On the move it is steady at just over half way.

 

Even so I used the heater a couple of times to cool it down when in standing traffic and if I did the journey again in the ambient temperature as it was of around 22/25 degrees C I think I would use a 74 degree thermostat.

 

I believe the running temperature for optimum power output is around 90 degrees, after which it falls off rapidly, but not sure what temperature has reached on a TR4A when it just hits the red sector. I am guessing in excess of 90 degrees?

 

I wondered if any other owners experienced overheating travelling over that weekend with standard fans or non standard electric fans?

 

Kevin

Edited July 23, 2016 by boxofbits

[Alfrom]

I've used an 82 deg thermostat for the past couple of years over ambient temperature ranges from about zero up to the low 30s and never had a problem - needle sits a fraction above the mid-point all the time the car is moving . Need to watch the dial a bit when getting into slow traffic after a good run though, as the temp will rise as a result of low air flow through the radiator. Switching on the electric fan as soon as the temp starts to rise has always been sufficient to keep the needle somewhere around the mid-point. There is no mechanical fan - just a Kenlowe fan under manual control.

 

Heater works OK (for a TR6) with the 82deg thermostat but was definitely not good enough with the previous 74deg

[SpitFireSIX]

Hi,

I run a modern three port 87 degree thermostat with fan switch on at top hose at 95 on and 92 off.

CP engine and VW rad. And more..

 

I would run the highest temp stat all year.

 

Cheers,

Iain.