24 replies to this topic

[shep_cobain]

Hi guys,

I have just had my head rebuilt and fitted the engine back together myself. I have had a new rad, water pump and 72c thermostat.

I have had the car at minisport today to get the timing right so I can drive the car and bed the engine in before it hits the rolling road later in may (their tuner is currently off).

I had the first drive today and took it for a 15 minute drive. It is extremely warm today and the temp of the car got to 100c on the gauge.

I did notice when starting the car from cold and slightly rev it it sometimes squeaks but then goes.

Minisport didn't mention anything about the temp. The guy did say he's set it to run a little richer... But is fine to drive.

Any ideas?

Cheers

[shep_cobain]

Hi guys,

I have just had my head rebuilt and fitted the engine back together myself. I have had a new rad, water pump and 72c thermostat.

I have had the car at minisport today to get the timing right so I can drive the car and bed the engine in before it hits the rolling road later in may (their tuner is currently off).

I had the first drive today and took it for a 15 minute drive. It is extremely warm today and the temp of the car got to 100c on the gauge.

I did notice when starting the car from cold and slightly rev it it sometimes squeaks but then goes.

Minisport didn't mention anything about the temp. The guy did say he's set it to run a little richer... But is fine to drive.

Any ideas?

Cheers

Any ideas?

[Cooperman]

Hi guys,

I have just had my head rebuilt and fitted the engine back together myself. I have had a new rad, water pump and 72c thermostat.

I have had the car at minisport today to get the timing right so I can drive the car and bed the engine in before it hits the rolling road later in may (their tuner is currently off).

I had the first drive today and took it for a 15 minute drive. It is extremely warm today and the temp of the car got to 100c on the gauge.

I did notice when starting the car from cold and slightly rev it it sometimes squeaks but then goes.

Minisport didn't mention anything about the temp. The guy did say he's set it to run a little richer... But is fine to drive.

Any ideas?

Cheers

Any ideas?

Incorrect temp gauge? What sort do you have?
Thermostat not fully opening?
Fan fitted the wrong way around? (a very common problem and reason for hot running)
Blockage in cooling system or radiator.

[shep_cobain]

Well the temp gauge is after Market but was working fine before head rebuild.

The rad fan is the right way round but seems to be closer at one side of the rad than it is to the other, doran appear to be 100% level.

The thermostat is brand new, what could cause it to stick and not open properly and how would I rectify or know if it was?

How would I remove any possible blockages in the cooling system?

Thanks

[Cooperman]

The most common cause of 'running hot' seems to be the accuracy of the temp gauge. Standard ones are really bad for this, but after-market ones are usually better, especially if they are of the capilliary-tube type. My own 'S' started going into the 'red' a couple of years ago for no apparent reason. I changed the gauge which cured it completely.
The fan should run in the centre of the shroud part of the rad cowling. It is a ducted fan and as such it is important to have the blades running close to the shroud.
Even a new thermostat can fail and you might check that it is of the correct one for the car as the temps at which they open are not all the same. If in doubt go for a cooler opening one,like a 74 deg.
If it still runs genuinley too hot, then it's probably a radiator issue. You can buy 'radiator flushing mixture' and flush the system out, but if it's a radiator problem a new rad is often necessary.
However, a Mini should not need a 'fancy' expensive radiator. The standard rad is fine and with the correct fan and 'stat so long as the rest of the system is in good order.
The thing to do is to establish whether the engine is really running too hot. If it's too hot, then it will be almost impossible to rest your hand on the top of the radiater, whereas at the correct temp of, say, around 70 to 75 deg you should be able to touch it for a few seconds. I know that's only a very rough guide, but it may help.
I hope all this helps.

[shep_cobain]

The most common cause of 'running hot' seems to be the accuracy of the temp gauge. Standard ones are really bad for this, but after-market ones are usually better, especially if they are of the capilliary-tube type. My own 'S' started going into the 'red' a couple of years ago for no apparent reason. I changed the gauge which cured it completely.
The fan should run in the centre of the shroud part of the rad cowling. It is a ducted fan and as such it is important to have the blades running close to the shroud.
Even a new thermostat can fail and you might check that it is of the correct one for the car as the temps at which they open are not all the same. If in doubt go for a cooler opening one,like a 74 deg.
If it still runs genuinley too hot, then it's probably a radiator issue. You can buy 'radiator flushing mixture' and flush the system out, but if it's a radiator problem a new rad is often necessary.
However, a Mini should not need a 'fancy' expensive radiator. The standard rad is fine and with the correct fan and 'stat so long as the rest of the system is in good order.
The thing to do is to establish whether the engine is really running too hot. If it's too hot, then it will be almost impossible to rest your hand on the top of the radiater, whereas at the correct temp of, say, around 70 to 75 deg you should be able to touch it for a few seconds. I know that's only a very rough guide, but it may help.
I hope all this helps.

Well to clarify, it's a brand new rad, brand new 74c thermostat and the rad fan might be positioned wrong, I will get a pic now and upload it see what you think. Like I said the temp gauge used to point to 80c and was fine but now goes to 100c and probably further. Giving we are having hot weather now but as you said after touching the rad it is very warm.

[shep_cobain]

[Carlos W]

Does the heater work?

[shep_cobain]

Does the heater work?

Will check.

[shep_cobain]

heaters are working fine.

[shep_cobain]

Took it for a drive for 5 minutes after leaving it to warm up and these were the gauges afterwoods:



The temperature went up very quickly! - The oil pressure was right passed 100.

[Cooperman]

The fan position is not ideal as the centre-line of the blades should be about 1/4" in from the edge of the shroud in the direction of the radiator face. A spacer will sort this and you need to measure what thickness you need then order one.
The temp today won't help. I just went 2 miles in my 1310 cc 'S' to buy some petrol and even though I don't have a thermostat, but a blanking sleeve instead, and it went to just under 80 deg C.
Check the stat and see what temp is marked on it. You could fit a blanking sleeve (as sold by Mini Spares) if it is still too hot, but don't try running with no 'stst as that causes the cylinders 3 & 4 to overheat locally.

[shep_cobain]

The fan position is not ideal as the centre-line of the blades should be about 1/4" in from the edge of the shroud in the direction of the radiator face. A spacer will sort this and you need to measure what thickness you need then order one.
The temp today won't help. I just went 2 miles in my 1310 cc 'S' to buy some petrol and even though I don't have a thermostat, but a blanking sleeve instead, and it went to just under 80 deg C.
Check the stat and see what temp is marked on it. You could fit a blanking sleeve (as sold by Mini Spares) if it is still too hot, but don't try running with no 'stst as that causes the cylinders 3 & 4 to overheat locally.

Ok, but there is a spacer there and before I took the engine out and had the head rebuilt the temps were fine. I don't understand why it is soo high now.

[Cooperman]

Just had another look at your photos. The fan position really is not good for optimum cooling. It must sit with the blade tip width completely within the shroud with the blade tips an equal distance all round from the shroud. If it doesn't, centrifugal force will allow some of the cooling air to bleed off before it gets into the shroud and thus reduce the air available for actual cooling.
You could switch to using a 6-blade steel 'export' fan as they are the best for cooling.

[shep_cobain]

Just had another look at your photos. The fan position really is not good for optimum cooling. It must sit with the blade tip width completely within the shroud with the blade tips an equal distance all round from the shroud. If it doesn't, centrifugal force will allow some of the cooling air to bleed off before it gets into the shroud and thus reduce the air available for actual cooling.
You could switch to using a 6-blade steel 'export' fan as they are the best for cooling.

Would it cause the temp to get so hifgh though?