AdamI1973

Hello all. This is my first post so please be gentle.

I drive a '94 Audi 80 with 2.0L 8V 4cyl engine and 152k miles on the clock.

Last Saturday, my coolant light started flashing during a short town-drive. I pulled over and had a quick look under the hood and there didn't appear to be any actual overheating going on, so I'm a bit stuck.

Here's what I know:

Coolant level OK
Water temp steady at ~90C (have fitted a new water temp sender as a precaution).
No coolant loss, so no leaks (hopefully).
Engine runs just fine (no "random" power loss, or other unexplained behaviour).

Anybody have any suggestions where I should look next?

Thanks in advance.

QCRAZY

Just Kidding ;-)

Add coolant. Very sensative system.

AdamI1973

Thanks, but the coolant level looks OK - it's between the MIN/MAX limits when pressurized.

I'll try bypassing the level sensor, and see if that stops the flashing warning light. If so, looks like I'll be buying a new expansion tank...

QCRAZY

Don't bypass anything. Just add coolant.

I've answered this question probably 100 times over the last 7 years. Just add some coolant already.

cuatrokoop

Ditto, just top it to the "Full" line, the sensor is HIGHLY sensitive. BTDT as well.

Audilard

Double Ditto....has to be at the "full" line, so so very sensitive!!! BTDT too.

All Wheel Driver

no matter how much coolant you add it still stays on.
I had to get a new overflow tank since the sensor was not available separately from the dealer.

AdamI1973

I tried adding coolant up to the Max line, but that didn't stop the warning light.

I tried bypassing the coolant level sensor, and that didn't have any effect either.

Having run out of ideas again, I called in on a local independent VW/Audi specialist. He suggested the first thing I should try was to remove the temp sender, clean any accumulated gunk from the sender and the mounting hole, then refit the sender.

I've done this, and it has fixed the problem. Woo-hoo!