# Red Warning Light regarding Coolant



## Justinway (Jan 18, 2005)

Hi, I have been reading this forum for quite a while and it has been really useful. I finally picked up my 1st TT last weekend purchased from a non Audi dealer locally.

I have an error that comes up on the dash when i start the car from cold. The coolant light comes on in the middle of the dash and bleeps at me, it is illuminated in Red. The warning stays on for about 40 seconds and then turns off and everything is fine (i hope!). A few things i have noted:

The car runs dead on 90 degrees when warmed up.

The light only comes on when the car is started after a long period of being turned off, i.e overnight. When leaving it for 3 or 4 hours no warning comes up

The coolant level is correct.

Any help you guys can provide will be appreciated. Thanks. Justin


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## sico (Feb 6, 2003)

Justinway said:


> Hi, I have been reading thsi forum for quite a while and it has been really useful. I finally picked up my 1st TT last weekend purchased from a non Audi dealer locally.
> 
> I have an error that comes up on the dash when i start the car from cold. The coolant light comes on in the middle of the dash and bleeps at me, its is illuminated in Red. The warning stays on for about 40 seconds and the turns off and everything is fine (i hope!). Afew things i have noted:
> 
> ...


Common problem, happens to mine all the time. You can try filling it up just above the max line as this sometimes work. Get some distilled water, dont use tap water.

Other than that just keep your eye on it. I have got used to it now!


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## mighTy Tee (Jul 10, 2002)

I also get this problem, but only when the outside temp is below about 1C and the car has been left overnight.

Running the engine for 30 seconds or so (reversing out of the drive) then restarting the engine has always cured the problem until the next cold night


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## sico (Feb 6, 2003)

mighTy Tee said:


> I also get this problem, but only when the outside temp is below about 1C and the car has been left overnight.
> 
> Running the engine for 30 seconds or so (reversing out of the drive) then restarting the engine has always cured the problem until the next cold night


Yes doesnt seem to happen in summer.


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## Justinway (Jan 18, 2005)

Thanks Guys. I was worried that i'd have a big dealer invoice ahead of me, looks like i'll just leave it as is.


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## NUM_TT (Apr 5, 2004)

I had that happen they replaced the temperature sensor(sender?) cured the problem. It has "chimed" up once or twice since but not everytime like it had been. I haven't had it come up for ages.


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## DXN (May 18, 2002)

topping up to full will help. this problem also occurs with the break fluid. for some reason the levels even when mid way between min and max.

break light warning is from my experience


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## Wak (May 6, 2002)

an older car of mine had this with the tank sensor getting dirty, I cleaned it and all was well.

I havent looked into the TT sensor, perhaps the unit above the arrow ( on the side of the tank) here can be withdrawn and cleaned?









it may be part of the tank so you'll have to see if its accessible, its usually 2 tips of metal that need a clean!

this may be a cause. :?


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## bilbos (Jan 16, 2004)

I had this on my A3. They replaced the temperature sensor and all is now well.


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## AllyD (May 16, 2021)

The red warning light indicates overheating or insufficient coolant. But as you've checked both those suspect the sensor. The most likely cause is poor electrical contact inside the plug. Disconnect the plug by squeezing the lugs and pulling it off. Clean the contacts with wet and dry paper wrapped around the end of a screwdriver. Plug it back in and check. If it persists it may be worth buying a new plastic expansion vessel.


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## Delta4 (Jun 19, 2015)

AllyD said:


> The red warning light indicates overheating or insufficient coolant. But as you've checked both those suspect the sensor. The most likely cause is poor electrical contact inside the plug. Disconnect the plug by squeezing the lugs and pulling it off. Clean the contacts with wet and dry paper wrapped around the end of a screwdriver. Plug it back in and check. If it persists it may be worth buying a new plastic expansion vessel.


First post and you revive a thread from 2005 that's epic :lol:


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