Rad Fan

[nxy]

Is it normal on a s1 for the fan to run when the car has just been started??? from cold the fan will run for about 10 seconds then swith off. When heading to Donnington setting off from a service station after quick stop, the engine was ticking over and the stack started to read 110-112, back on motorway settled down to 86 ish.
When i got home i left the car to idle and noticed the fan came on when the stack was reading 108 but with the fan on it still crept up to 112 once i increased the revs to 1500rpm the temp started to drop steadily, do i have air trapped in the system????
1, do i have the begining of a problem?
2, is this normal?
3,will i win the lottery this weekend?

ian

[robin]

Is it normal on a s1 for the fan to run when the car has just been started??? from cold the fan will run for about 10 seconds then swith off. When heading to Donnington setting off from a service station after quick stop, the engine was ticking over and the stack started to read 110-112, back on motorway settled down to 86 ish.
When i got home i left the car to idle and noticed the fan came on when the stack was reading 108 but with the fan on it still crept up to 112 once i increased the revs to 1500rpm the temp started to drop steadily, do i have air trapped in the system????
1, do i have the begining of a problem?
2, is this normal?
3,will i win the lottery this weekend?

ian

You almost certainly have air in the system - either from a leak or HGF. You can bleed it out at the radiator easily enough, it will take a few attempts to get all the air out.

If the fan runs when you first start it and the engine is cold, you probably have a broken ECU temperature sensor. However, if you turned off the engine when hot, walked away for 10 minutes, then started it again, it's not unusual for the fan to kick in momentarily due to heat soak from oil to coolant in engine block - but it shouldn't last long in normal ambient temperatures as the radiator will be full of cold coolant.

Cheers,
Robin

[nxy]

Cheers Robin will try to look for leak, Campbell did say that there was a mod on the route of the cooling system, mine is the one with the pipe running along the top of the engine (1997) where possiable air locks could be created?
Hope it is not HGF in the history the engine was redone 20000 miles ago due to HGF, but i suppose it can happen any time.
where is the ecu temp sender positioned?

[robin]

Sometimes there is a bleed nipple brazed onto the up-and-over coolant rail.

The ECU and stack sensors are both connected to the water elbow on the corner of the head nearest the pax seat.

Cannot remember which is which, but if you disconnect the dash one the dash will go blank; if you disconnect the ECU one, the ECU will turn the fan on.

Cheers,
Robin

[Rich H]

Watch out for the top rail bleed screw, its brass in aluminium, if its been overtightend it will strip the threads out of the pipe stub

That is the highest point in the system though so check there for air first.