Coolant warning light (orange)

Turbo Killer · Post by **Turbo Killer** » Mon Sep 26, 2011 4:42 pm

The first temperature warning light has started to light up after a mile or so, i replaced the sensor and cleaned up the big brown connector block on top of the gearbox, still no improvement. I noticed the radiator was not getting very hot and i can remove the expansion tank cap with no problems, the car is not overheating or in distress, the heater also works fine. As a matter of course i have changed the thermostat and flushed the coolant out, i also removed the radiator and gave it a good flushing, but the problem still persists, i am now thinking maybe the coolant flow is poor and the pump is inefficient ? Do you guys have any ideas or experienced this problem before?

Post by **Defender110** » Mon Sep 26, 2011 4:51 pm

What engine are we talking about? The TD has 2 water sensors from memory and they are prone to playing up occasionaly?

Turbo Killer · Post by **Turbo Killer** » Mon Sep 26, 2011 5:00 pm

Its a 1.7 turbo diesel engine.

Post by **Defender110** » Mon Sep 26, 2011 5:32 pm

I have heard of impellars coming loose and not spinning properly but not on a BX and this would cause the engine to overheat which it clearly isn't. To me it still sounds like a sensor proplem and there should be 2 on your engine next to each other on top of the stat housing, could it be the one you haven't changed?

Post by **mat_fenwick** » Mon Sep 26, 2011 5:48 pm

How do you know the engine isn't overheating without a gauge though...?

I do agree that it would seem to be a sender problem as I can't see how the engine could get that hot within a mile of a cold start. As Kevan says there are 2 on top of the thermostat housing. From memory the one with the yellow connector is for the orange light but the sender (strictly a switch) has the temperature marked on it to be certain. 105°C for the orange lamp and I think 110 or 112°C for the red lamp.

Turbo Killer · Post by **Turbo Killer** » Mon Sep 26, 2011 6:01 pm

Yes it has two sensors on the t/stat housing, one above the other, if i remove the yellow connector the light goes out, so i am sure i have replaced the correct sensor, to add to the mix, if i put the connectors on the wrong sensors, the red warning light glows, so something appears to be suspect with the wiring?
As for not overheating, if it was overheating I'm sure i would have difficulty removing the expansion tank cap safely?

Post by **mat_fenwick** » Mon Sep 26, 2011 8:36 pm

Sorry, I got the colours the wrong way round. The yellow connector (green wire) operates the red lamp, the grey connector (brown wire) the orange lamp. To test the wiring simply short each connector to earth in turn and the respective lamp should light up.

rmattila · Post by **rmattila** » Mon Sep 26, 2011 9:00 pm

to add to the mix, if i put the connectors on the wrong sensors, the red warning light glows, so something appears to be suspect with the wiring?

Are you sure the new sensor is for the warning light (on/off) and not the analogue one for the temp gauge? The symptoms sound as if you were using a temp gauge sensor with a warning light.

(I do that on purpose on two of my BX:s, since I like the analogue information: when the light is dim, everything is OK; if it turns too bright, the engine is running warm. And it lights within about a mile.)

Post by **mat_fenwick** » Wed Sep 28, 2011 9:43 am

That sounds a very plausible answer - the sensors for the warning lights are about 1" longer (externally) than the sensor for the gauge.