16 replies to this topic

[AC&SONS]

So, with the RSP having no electric cooling fan, the temperature gauge sometimes sits slightly above normal if we are sat in traffic for a while or the engine is under load for a long time.

 

It normally drops back if we put the heater on or the traffic conditions ease but I was wondering if a change of thermostat might help.

 

I seem to recall from Minis I have had in the past that there are two different values of thermostat that can be fitted so I was wondering what people's thoughts were on the best one for the Summer months to try and help with this issue.

 

Thanks

 

[nicklouse]

Lower number for the warmer months, higher number for the colder months.

[Midas Mk1]

I run 74 during summer, 82 in the winter with a grille muff, daily driven in any weather.

[mbolt998]

In theory you should just run the right one for your car at all times (which for mine is 88, but I think I have an 82 in there atm).

[nicklouse]

In theory you should just run the right one for your car at all times (which for mine is 88, but I think I have an 82 in there atm).

Nope. The Mini was designed at a time when you changed your tyres over for winter or summer use. Running a 72 stat in the winter will lead to lack of heat in the engine. Running a 82 in the summer will lead to an engine that is running too hot.

[andyapanel]

I run an 88 in my RSP. An 88 will give you maximum economy and my extra fan rarely comes on.

Sat in traffic will definitely make the engine hot in the summer. 

 

However, the thermostat may be sticking, your radiator could be sludged up and I would change the water pump (Minispares Evo).  Change the lot if you are worried, though you may want to book in the thermostat swap to a mini expert; they can and do corrode. If you go down that route, try cracking the nuts by slightly tightening the nuts before trying to undo them. 

 

I don't think that just changing the thermostat's opening temp is going to be helpful. 

[mbolt998]

 

In theory you should just run the right one for your car at all times (which for mine is 88, but I think I have an 82 in there atm).

Nope. The Mini was designed at a time when you changed your tyres over for winter or summer use. Running a 72 stat in the winter will lead to lack of heat in the engine. Running a 82 in the summer will lead to an engine that is running too hot.

 

There's nothing in the owner's handbook about changing the thermostat between summer/winter.

[sonscar]

Is it fuel injected?The correct stat is essential for correct fuelling.Ignore this if it has a carb.Steve..

[AC&SONS]

I'll check which one is in at the moment and if it's the 82, I'll change it for a 74; thanks for the information guys.

[4130]

I was under the impression that an 82 thermostat was best for road performance based on Calver's article. Am I misinterpreting him?

https://www.calverst...nt-temperature/

[roblightbody]

I had read that for the later cars, the ones designed to run on unleaded from the start, the 88C thermostat was what they are all designed for, and gives the best balance of power and efficiency - the same reason all modern cars run at at sround this temperature i believe.  My Mini has been fitted with an 82C one, which annoys me because the temp gauge never quite gets to normal.

[andyapanel]

My gauge usually under reads, too and it has an 88.

[Ethel]

I had read that for the later cars, the ones designed to run on unleaded from the start, the 88C thermostat was what they are all designed for, and gives the best balance of power and efficiency - the same reason all modern cars run at at sround this temperature i believe.  My Mini has been fitted with an 82C one, which annoys me because the temp gauge never quite gets to normal.

 

 

This is a valid point, even if yours was designed for different thermostats, the petrol available now wasn't. Likewise engine oil.

 

Once the thermostat is open it's not going to improve cooling performance. 

 

4 litres of water  at + or - 10^c will make about 168kw difference. That's about the full power from three standard 1275s. That suggests to me the coolant temperature wont be the limiting factor in keeping it from overheating.

[68+86auto]

Just fit an 88 or 82 and leave it all year round.

[Steam]

Over here in Aus an 82 does all year round, you may need a higher one in Europe but changing it every 6 months is just a PITA.