17 replies to this topic

[minitalia1275]

I have a 1990 Mini 998. It gets very hot while driving especially up hills and excessive load but cools down while stationary in traffic etc.
I am in Italy and it has been a very hot summer, always over 30 degrees. Only hot air getting to the engine.
I have stopped the car before overheating when the gauge is at 3/4.
The cooling system is in good condition with many new parts.
I would appreciate any advice/opinions on the cause of this problem. I am assuming that it is the hot summer that is causing the problem but I have never had it on other Mini's I have had in equally hot weather.
Thanks
Rob

[Icey]

Check your timing and fueling. To retarded or lean respectively can cause overheating.

Edited by Icey, 20 August 2017 - 01:33 PM.

[Northernpower]

I have a 1990 Mini 998. It gets very hot while driving especially up hills and excessive load but cools down while stationary in traffic etc.
I am in Italy and it has been a very hot summer, always over 30 degrees. Only hot air getting to the engine.
I have stopped the car before overheating when the gauge is at 3/4.
The cooling system is in good condition with many new parts.
I would appreciate any advice/opinions on the cause of this problem. I am assuming that it is the hot summer that is causing the problem but I have never had it on other Mini's I have had in equally hot weather.
Thanks
Rob

Check the percentage of anti freeze. Anti freeze is not a good coolant and if its too strong a mix the thermal efficiency is not good.

[minitalia1275]

Check your timing and fueling. To retarded or lean respectively can cause overheating.

Yes it could be the timing. I haven't checked it yet because the car runs perfectly. The carb set up seems to about right. Slight fouling on the plugs but I will check that also. Thanks

[minitalia1275]

I have a 1990 Mini 998. It gets very hot while driving especially up hills and excessive load but cools down while stationary in traffic etc.
I am in Italy and it has been a very hot summer, always over 30 degrees. Only hot air getting to the engine.
I have stopped the car before overheating when the gauge is at 3/4.
The cooling system is in good condition with many new parts.
I would appreciate any advice/opinions on the cause of this problem. I am assuming that it is the hot summer that is causing the problem but I have never had it on other Mini's I have had in equally hot weather.
Thanks
Rob

Check the percentage of anti freeze. Anti freeze is not a good coolant and if its too strong a mix the thermal efficiency is not good.

I have used pre mixed (ready to us) antifreeze. I don't know much about it. It has been in my garage unused for 20 years!
Thanks

[bikewiz]

Is it boiling over or are you assuming it will because the gauge is reading high? The factory electric gauge in the 3 clock dash in my similar year mini is notoriously inaccurate, it will read below half way when my capillary analog gauge reads 190F/87C. If it isn't actually boiling over then it could be false readings on the gauge.

[minitalia1275]

Is it boiling over or are you assuming it will because the gauge is reading high? The factory electric gauge in the 3 clock dash in my similar year mini is notoriously inaccurate, it will read below half way when my capillary analog gauge reads 190F/87C. If it isn't actually boiling over then it could be false readings on the gauge.

No, not boiling over, but the usual overheating signs are there, the smell, the heat, higher tick over. It only happens in hot weather. Fine in the morning when I go to work but very hot at 5ish when I return home.
Thanks.

[jakejakejake1]

Worth checking the fan in mounted the correct way around (often it is the wrong way which reduces its efficiency). 

 

If you need to, set the heater to hot and put the blower on which should get rid of some of the heat (although obviously somewhat uncomfortable in hot weather!).

[minitalia1275]

Worth checking the fan in mounted the correct way around (often it is the wrong way which reduces its efficiency). 
 
If you need to, set the heater to hot and put the blower on which should get rid of some of the heat (although obviously somewhat uncomfortable in hot weather!).

The fan was actually mounted incorrectly. I have since fitted it correctly but it makes little difference.
Yes, I have have had the heater on blowing hot, it does actually work and reduces the water temp to halfway.
Thanks

[CityEPete]

Timing, valve clearances and condition of ht leads,coil and plugs would my first places to check along with making sure the radiator is letting the coolant flow through all it's cores properly. Water pump in good health?

[Magneto]

Which fan blade do you have?

 

The metal "tropical" fan (6 blade?) is supposed to be the best for hot weather.

 

Where I live the temps routinely go over 38-40*C, I had to add an additional heater core for extra cooling in the summer on my first car, I used a shut off valve to close it off in winter.

 

Another alternative is to fit an aluminum radiator - I've fitted them to several cars with excellent results - my current 89 with 1275 has one and needs no additional rad or special fan to run perfect temps - at $60 shipped to the US on Ebay, it was a great buy and I've had no trouble with any of the ones I've installed.

[minitalia1275]

Timing, valve clearances and condition of ht leads,coil and plugs would my first places to check along with making sure the radiator is letting the coolant flow through all it's cores properly. Water pump in good health?

Timing and valve clearance are spot on, I checked them today. New plugs but old ht leads, they need changing asap. New coil fitted recently. Not sure about the water pump. It turns freely without any play and without making any strange noises. The rad seems to be ok and the fluid is always clear but it would be a good idea to give a proper cleaning. It is from a Mini SPI. I wouldn't imagine that it would make much difference.
Thanks

[minitalia1275]

Which fan blade do you have?
 
The metal "tropical" fan (6 blade?) is supposed to be the best for hot weather.
 
Where I live the temps routinely go over 38-40*C, I had to add an additional heater core for extra cooling in the summer on my first car, I used a shut off valve to close it off in winter.
 
Another alternative is to fit an aluminum radiator - I've fitted them to several cars with excellent results - my current 89 with 1275 has one and needs no additional rad or special fan to run perfect temps - at $60 shipped to the US on Ebay, it was a great buy and I've had no trouble with any of the ones I've installed.

It has the standard plastic fan fitted. I was thinking of fitting an aluminum radiator. I have had them in the past and have never had problems with overheating. I have seen them fitted to many Mini's here, usually with the metal fan blade.
Thanks

[imack]

I think I had this problem many years ago of engine running hot when driven/under load but temperatures normal at idle, it was the plastic impeller loose on the water pump.
If I ran the engine from cold with the heater hose disconnected from the heater valve and revved the engine coolant would come out of the valve with force.
Do the same thing with the engine at running temperature and the coolant would dribble out of the valve where the impeller was becoming a loose fit on the pump shaft when hot.
If you try this, add a length of heater hose to the heater valve and the other end of the hose into a bucket then you can reuse the coolant and not make the mess that I did!

[minitalia1275]

I think I had this problem many years ago of engine running hot when driven/under load but temperatures normal at idle, it was the plastic impeller loose on the water pump.
If I ran the engine from cold with the heater hose disconnected from the heater valve and revved the engine coolant would come out of the valve with force.
Do the same thing with the engine at running temperature and the coolant would dribble out of the valve where the impeller was becoming a loose fit on the pump shaft when hot.
If you try this, add a length of heater hose to the heater valve and the other end of the hose into a bucket then you can reuse the coolant and not make the mess that I did!

Thanks. Did replacing the water pump to resolve the problem?