Coolant Warning Light

[Middle7]

Hi,

 

I wonder if anyone can give some advice regarding the operation or mis-operation of coolant waring dash light? The coolant warning light on my 7 comes on intermittently, more often than not after going over speed humps or ascending/descending steepish hills. I have checked the coolant level and that seems fine, about an inch below the neck. I'm beginning to wonder whether it might be a fault with the warning light delay unit, but I'm not sure where to look for it or how to test it when I find it.

 

Thanks.

 

Forgot to mention that the car is a 1980 dhc

Edited August 23, 2007 by Middle7

[TR8IAN]

Have you checked the wire connection to the low water level probe on the expansion tank? - quite often this is the problem. give it a clean see what happens then.

 

Good luck

Ian.

[Middle7]

I have had a look at the wiring to the LW probe and given it a clean, but no change.

 

What voltage should I expect to see between the end of the supply wire and earth when it is disconnected from the LW probe? I assume 12V but I'm only getting 1V.

 

Also, where does the probe earth? With the supply wire removed, if I measure the resitance between the connector on the probe and earth I get an open circuit. This makes me wonder if the probe is fault. Although, as it is mounted into the tank in a rubber bush it seems difficult to work out how it gets a return path to earth. The wiring diagram in the Haynes manual isn't much use either.

 

When the tests above were carried out the coolant dash light was illuminated, ie indicating low coolant even though the header tank was full.

 

Normally I wouldn't worry too much about an intermitent light, but as the 2.0l engine has a bit of a reputation for head gasket failure I don't want to leave anything to chance!