Low water light on at cold start

[Kezbo 0]

1993 Corrado VR6

 

I have an annoying problem with the low coolant warning lamp flashing a few seconds after starting the car from cold. The light will come on a few seconds after starting and will stay on until you switch the car on and off, after running for a few mins then restarting the light will not come on again.

 

The coolant level is perfect so not a problem there.

 

The fact that is goes off once the engine has warmed a little and restarted would indicate to me that there is a heat related poor connection somewhere?

 

At the weekend I tried to measure the resistance over the spikes in the expansion tank by taking the plug off and putting a multimeter on the two connections. The multimeter showed infinate resistance, but I would expect that the there would be a slight connection (as the current runs through the water to connect the crcuit, right?). So does this point to the expansion tank being alittle defective, but what I dont understand is why will the warning light go out when the car is warmer? There are no moving parts in the expansion tank etc...

 

I thought a test would be to unplug the connection into the expansion tank and bring the connection with a wire (i.e. completing the circuit as it would through the water) thus removing the expansion tank from the equation. Would this cause any damage do you think?

 

Any thoughts would be greatly appreciated as this has me stumpted!

 

Thanks

[Jim 2]

I've got the same problem on my motor mate and have done for the last year or so. As you say, once the car is warmed up, if you stop and start the car you don't get the flashing light any more. If you manage to find out what causes it, please let me know! :)

[Jon_vr6 1]

I would have thought coolant sensor??

[Kezbo 0]

Glad im not alone! Its really annoying aint it, having to start the car 2 or 3 times before setting off!! Even though I know the water level is not low I hate driving it with the light on....

 

Hopefully someone will come along soon and have an answer :salute:

[Kezbo 0]

I would have thought coolant sensor??

 

Do you mean the sensor in the expansion tank (i.e. the 2 spikes?) or the temperature sensors? Is there a pressure sensor too?

 

I thought the only thing linked to the coolant light was the expansion tank?? I might be wrong

[Jim 2]

My expansion tank is genuine VAG and only a year or so old. No matter how much coolant is in the tank, the light still flashes when the car is cold.

[Kezbo 0]

My expansion tank is genuine VAG and only a year or so old. No matter how much coolant is in the tank, the light still flashes when the car is cold.

 

So is mine, maybe 2 to 3 years old. I was wondering if the tank was abit dodge, given you have the same prob on the same age tank I think it will be worth changing mine to see if it makes a difference.

[Jon_vr6 1]

Im meaning the level sensor in the coolant expansion bottle being faulty or needing cleaning!

[Jim 2]

Stealth think they cracked this one today when I had my car in for a service. They changed the expansion tank again and no dice - but then examined the connector and found one of the pins bent back in the plug. Bent it back and replugged it - and no more flashing light! Result! Might be worth checking the plug if you haven't!

[Kezbo 0]

I just fitted a new expansion tank and that sorted the light. I will have a look at my old tank to see if the connectors are bent though....