4 replies to this topic

[BechAndersen]

A couple of years ago my wife bought an automatic Mini Mayfair 1989 (998cc) for use with our Classic Car Club on the South coast of Spain. The car looks like a diamond and has no rust BUT we have an over-heating problem.

 

On the first trip out we “cooked” the car going up a mountain and the result was a blown top gasket. Our mechanic replaced the radiator with a new one with 50% greater capacity but little changed. An additional electrical fan was added but the car was only happy pottering around town and still got hot between towns not to mention up-hill. We have now changed mechanic and the new one found that the timing is way out. It should be between 5 and 8 deg., he thinks, but the engine will only run smoothly at 20 deg. which results in lack of power and over heating. The valve setting is almost correct and any discrepancy would not account for the timing being way out. The mechanic is now looking at the carburettor but he needs inspiration if not a life line. He hasn’t played around with Minis for a very long time and I wonder if you could point us in the right direction.

Best regards,
Karsten

Member of SOL Classic Car Club (Costa del Sol)

 

[wile e coyote]

First get the timing, valve settings  and fuel mixture right. Then remove the radiator  and flush the cooling system - refilling with diluted coolant not water and  fit the lowest temp rated thermostat you can - think 74 degrees is the lowest currently available and if that doesn't cure it possibly consider renewing the water pump (with a large impeller variant - see Minispares site)) - you may have one fitted that's corroded, knackered or was a cheap aftermarket one in the first place - some are really bad) and fitting a smaller pulley to get more fan speed (don't forget to buy the shorter belt)..... and if that still doesn't sort it - assuming your current fan is mounted the right way round .....(not unusual to see them on backwards) consider that temperatures where you are are generally (not right now!) higher than the UK fitting an "export" 6 blade fan (that was the 60's factory solution!).....

 

The good news is none of that is particularly expensive - and I'd bet that'd fix it.......

 

The remaining q - is you say you were going up a mountain... how high?? Pushing a carbed car where the air is thinning is guaranteed to cause higher running temperatures and wheezy performance...

[sonscar]

I am not convinced changing the thermostat has any effect on cooling except that it heats up more or less slowly before the water circulates.Could be useful in very cold climates to keep the engine hot at the slight risk of freezing the radiator.Steve..

[Cooperman]

Overheating can be caused by the following:

Blocked or damaged radiator.
Defective or poor quality water pump.
Wrong size water pump pulley.
Stuck thermostat.
Incorrect ignition timing.
Cropped fan blades.
Fan not positioned correctly with respect to fan shroud - it must sit centrally in the shroud.
Incorrect fuel/air mixture.
Blocked or corroded water ways in block.

[Spider]

With it needing so much initial advance, I'm wondering it the Distributor Advance Mech. is jammed or broken ?

 

A very common cause of overheating I've found is rusted cooling jacket in the block and head. I'd also suggest doing away with the electric fan. It will help in start  stop slow traffic, but outside of that, all it's going to do is obstruct air flow.