why winter and summer thermotat temp?

[recordsj]

Why for our MGs do they specify a winter and summer thermostat temp? What is the reason?

In modern cars, this is not specified for a winter and summer thermostat.

 

[urchin]

I can't speak for Spridgets directly but here's my take on this based on my Land Rover experiences.

First the sports cars have small radiators in terms of size, surface area and capacity. Secondly, the heaters and defroster units on British cars were [are] pretty small for North American use; when our temperature ranges, such as in fall and spring, approximated the British experience, they were adequate. But when the temperatures fell in winter, the heaters couldn't put out enough heat. One answer was to raise the engine's temperature before the thermostat opened. So my Land Rover has an option for a winter thermostat.

When summer temperatures soared past those common in the UK or similar export markets, you needed a thermostat that would open at lower temperatures to try and reduce the chances of running too hot or overheating.

I still swap mine out twice a year in my Land Rover. By the time of my '80 TR-7's production the radiator and fan units could handle US conditions, winter and summer, successfully, so no swap out was required. I've driven mine year round in northern New England and the heating system and cooling system can handle the extremes successfully.

In my past life with a '63 and a '78 MGB, a '62 and a '78 Spitfire, and a '72 Mdiget, all used and all driven year round in northern New England, I always had to run a piece of cardboard in front of the radiator during the depths of winter to get enough heat into the car.

Jeff

 

[recordsj]

but even older American cars (GM, Ford, etc.) had winter and summer thermostats.

 

[Blueghost]

Keep in mind that nearly all engine wear happens if the first few minutes when dimensional clearances are not yet stabilized, and oil is not yet flowing best. Not much a problem in Florida, but in Minnesota a block heater does more than just give you faster heat, it preserves engines. Get it to temp as quick as practical. If you aren't overheating in the summer, run a 190 F all year. This is especially true for aluminum parts as they have a higher coefficient of expansion. Aircraft engines need preheat in cold areas.