Aw11 Temp Sensor

August 23, 2006

After noticing that the under bonnet cooling fan on my '2 (an '88 Rev.B) was coming on more frequently than before, I decided to change the sensor (mounted in front of the nearside/rear corner of the cylinder head). As I already have an old '85 Rev.A model that I'm slowly cannibalising (Need any bits?!?) I didn't envisage too much of a problem. However, inspection revealed a difference; on the Rev.A the sensor is mounted with the connecting plug at the bottom, whereas on the Rev.B the sensor is mounted "upside down" with the connector at the top. If the sensor is mounted like this on a Rev.A the fan runs continuously so could somebody clarify the position. Which way up should I mount the substitute sensor- plug down as originally fitted or sensor up as in its' original placement? Or are the 2 parts incompatible? Any advice would be welcome

thanx,

J&A

August 25, 2006

I have three MK1's in the family.

1a, 1b and a Super Charger. The engine bay temp sensor you're refering to is the same orientation on all three. Like your 1b (rev.B).

I don't think it will make any difference which orientation it is though as with the amount of airflow going through the engine bay, it's basically measuring ambient temps.

If the fans are running continueously, it's either because the wiring/connector is mashed or the sensor is knackered.

The fan shouldn't need to come on frequently. You need to find out why the temps in the engine bay are getting so high. Check your coolant, make sure there's no air in the system. Also make sure all the heatshields are still in place where they aught to be. Also make sure the air filter is getting enough direct cold air.

Saying that though, on my 1a which is a track car, I leave the sensor disconnected and the fan running continueously. This is because the car sits between 6000 & 7200rpm all day most times it's driven. It doesn't do any harm.

the orange show car has an inherent problem where the fan comes on virtually every time it's driven and also the engine temp warn light comes on the dash. We can't find any faults so just keep our eyes on the gauges and make sure coolant temps and oil pressures are bang on all the time.

The Super Chargers fan comes on quite often, but that is because the engine bay gets much much hotter as there is less air circulation due to all the additional gubbins on the engine - the main thing being an aftermarket doublesized intercooler.