Golf VR6 Low coolant warning light flashing

[gordon156]

Hi all

I've got a Mk3 Golf VR6 which has a problem with the low coolant warning light. About ten seconds after startup, the light starts flashing even though the coolant level is OK. I've checked all the connections and wiring at the expansion bottle, and even tried another bottle with no luck.

The local performance car garage spent a while trying to find the problem, but when the bill had reached £60 with no result, they asked me if I wanted them to continue and I said no thanks.

Any ideas much appreciated.

[kite]

Try clening the level sensor in the bottle.
Give the prongs a scrape with a screwdriver

[gordon156]

I tried that and then tried another bottle in case the prongs were faulty, but no change. I even tried shorting the plug that connects to the bottle, thinking that completing the circuit like that is the same as the prongs do when the coolant level is OK, but still no luck.
Does the circuit go through some sort of ECU type thing that could be faulty?
Thanks for the idea.

[AJ3000]

I'm having the same problem with my TDi. light comes on flashing at EXACTLY the same point in the road, regardless of how far i have previously driven. unfortunately i can't offer a soloution, but it doesn't seem to be causing any problems with the car so my advice......take the coolant bulb out of the dash! out of sight, out of mind..... problem solved (sort of)

[euroslap]

I'm having the same problem with my TDi. light comes on flashing at EXACTLY the same point in the road, regardless of how far i have previously driven. unfortunately i can't offer a soloution, but it doesn't seem to be causing any problems with the car so my advice......take the coolant bulb out of the dash! out of sight, out of mind..... problem solved (sort of)

This is bad advice I'm afraid, it'll be out of sight & mind until you've got a blown head gasket or cracked head/block. Find the route and fix it.

[AJ3000]

This is bad advice I'm afraid, it'll be out of sight & mind until you've got a blown head gasket or cracked head/block. Find the route and fix it.

Of course, you are right my friend. i have tried to trace the route without success, having said that, i have also done a complete engine swap on my car, and it is still doing the same thing! i'm wondering if it is an electrical fault somewhere down the line?

[euroslap]

Of course, you are right my friend. i have tried to trace the route without success, having said that, i have also done a complete engine swap on my car, and it is still doing the same thing! i'm wondering if it is an electrical fault somewhere down the line?

In this case it's almost certainly a wiring fault, I'd trace the wiring back from the bottle sensor and try and find a pinched or shorted out wire as you've pretty well eliminated everything else.

[euroslap]

Of course, you are right my friend. i have tried to trace the route without success, having said that, i have also done a complete engine swap on my car, and it is still doing the same thing! i'm wondering if it is an electrical fault somewhere down the line?

Have you changed the header tank to eliminate the water level sensor?

[AJ3000]

yes indeedy. everything under the hood was swapped out by me personally at the time of the swap. i also had the same thought as you with a pinched wire, traced it back but couldn't see anything. maybe i'll just rip the wiring out and start again. if that don't fix it, then i WILL just take the bulb out of the dash and if it goes pop then i'll deal with it! hahaha!

[gordon156]

Thanks for the replies. I too had thought of taking the bulb out as the coolant temperature gauge is stilll working and that should do to warn if anything is overheating under the bonnet. I'll do the checking the wiring option all the way back first and let you know if I find anything.
Cheers.