Club 80-90 Forums

Just a few comments that may help others with a random flashing LED in the temp gauge, but coolant level and temp are both ok when checked.

After the LED started flashing on a run it all checked ok but the LED would sometimes stay off, after the startup check flashes, until engine stopped and re-started when it would flash again continously.
Earth crowns checked and sensor probes cleaned but no fix from that although there was a slight difference.

I then found that if I turned ignition on and waited the 4-5 seconds then started the LED would stay off. This also worked on the re-start when hot.
As the blue coolant was 2 1/2 - 3 years I drained, flushed and refilled with red G12+ (the Europarts version).
Result! LED now works as it should - its only been a couple of days so far but hopes are high as this is an important warning - after losing coolant several times before!

The factors contributing to the LED flashing for no reason seemed to be an out-of-date coolant.

This has been mentioned in the Wiki I think.
Obviously there can be many other electrical and wiring causes but this seems to have been the case here.
And perhaps the K-seal but that had been in for many months to fix a minor coolant loss that I could find no cause for.

So if this helps anyone else or if anyone has any comments please feel free to add to this. It has been frustrating - but interesting!

I know that pure water is actually not a particularly good conductor of electricity. The probes in the header tank use some fairly complex system of pulses of voltage, not a simple measure of conductivity. This means that if you have very pure water (as is available from some taps in some areas) the "system" won't work correctly. Perhaps either you did not have enough coolant additive, or what you did have was also not a good electrical conductor.
Anyways, glad you got your LED working as VW intended

Yep, thanks ghost.
Very pleased to have to LED working again because it did save the engine on several previous occasions before sorted and I was nervous with not having that warning system working!!

croc wrote: Very pleased to have to LED working again because it did save the engine on several previous occasions before sorted and I was nervous with not having that warning system working!!

Agreed

A year or more ago I actually did a post called summat like "check your low coolant warning system" after I had a narrow escape It resulted in quite a few posts from folk who's system was not working correctly