Temp gauge not working? '98 A3 T Sport

[martinb!]

Hi,

Not had the car long but i have noticed my water temp gauge does not seem to work / does not ever move off the bottom. Any advice for common faults or what to check?

Cheers in advance.

Martin

 

[Ian_83]

If its anything like mine, its the thermostat stuck open. Have you let it tick over on a warmer day for 15 minutes to see if it gets warm?

 

[CHRIS555]

Extremely common fault on all VAG cars - 99% sure it will be your TEMPERATURE SENSOR - I changed mine a week or so a go and only with i'd done it sooner - more MPG and more power!

You can buy the sensor from a dealer for around £20-30 - make sure you get the clip and o ring with it (they will know what they are) or you can get them of ebay cheaper - audi a3 temperature sensor items - Get great deals on Vehicle Parts Accessories items on eBay UK!

This is such a common fault that most dealers keep them in stock all the time.

When mine went the needle just did not move. It will be giving your MAF funny readings and most likely running rich (using more fuel) and losing a little power. Well worth a few quid trying this.

 

[martinb!]

cheers for the replies

If its anything like mine, its the thermostat stuck open. Have you let it tick over on a warmer day for 15 minutes to see if it gets warm?

Will try that if and when we get a warm day. I let the car tick over for ages when i bought it and it didnt move

Extremely common fault on all VAG cars - 99% sure it will be your TEMPERATURE SENSOR - I changed mine a week or so a go and only with i'd done it sooner - more MPG and more power!

You can buy the sensor from a dealer for around £20-30 - make sure you get the clip and o ring with it (they will know what they are) or you can get them of ebay cheaper - audi a3 temperature sensor items - Get great deals on Vehicle Parts Accessories items on eBay UK!

This is such a common fault that most dealers keep them in stock all the time.

When mine went the needle just did not move. It will be giving your MAF funny readings and most likely running rich (using more fuel) and losing a little power. Well worth a few quid trying this.

Sounds like the symptoms i have as the maf is giving odd readings. Looking through the history the car has had a recent maf and thermostat. There are also receipts for green and blue temp sensors (and also a credit note for the green so perhaps returned unfitted?). At that price though, i may just try them anyway.

Cheers

Martin

 

[s3dave]

It is the green one that is more reliable

 

[martinb!]

Is there any way of telling which I need or do you reckon its best just to change both?

cheers for the advice

 

[Welly]

Is there any way of telling which I need or do you reckon its best just to change both?

cheers for the advice

Change both the stat and the sensor. Remove all possibilities.

 

[aragorn]

Or perhaps just diagnose the problem properly and only replace the part thats broken. I know its only a 20quid part, but its the thaught process behind just randomly throwing parts at a problem that really ****** me off with modern "mechanics".

Give the car a run, then park up and leave it idling for 10mins. If the needle starts to climb then change the thermostat. If it doesnt, its probably the sensor.

If you have climate control, you can view the current coolant temperature on there, which will give you an idea. Hold recirc, and press up, display should change to "1c" use temp control +/- to make the display read 49c, then press recirc again, and the display will show you the current coolant temp.

Do that with the engine cold and you'd expect to see ambient temperature, 5-10c or something, and it should then start to climb as you drive it. You'd expect to see 90c within about 5-10mins of driving. If the thermostat is away, it will climb slowly, will level off at some low temperature, and will fall the faster you drive.

 

[Welly]

Or perhaps just diagnose the problem properly and only replace the part thats broken. I know its only a 20quid part, but its the thaught process behind just randomly throwing parts at a problem that really ****** me off with modern "mechanics".

I disagree - if it were me I would be replacing both parts. I don't see the requirement to avoid 'throw away mechanics' when it makes the water temperature management system on the car more future proof.

You are simply pre-empting failure of a part which is known to fail.

Still, each to their own.

 

[Westy]

I like to change as much as possible but that's just me. I'd rather change both parts now and avoid having to do 1 part now and another part a few months down the line!

 

[martinb!]

I'm not a mechanic by a long stretch and dont really know my way round these engines well yet so any advice is appreciated, thanks again for all your replies.

Give the car a run, then park up and leave it idling for 10mins. If the needle starts to climb then change the thermostat. If it doesnt, its probably the sensor.

If you have climate control, you can view the current coolant temperature on there, which will give you an idea. Hold recirc, and press up, display should change to "1c" use temp control +/- to make the display read 49c, then press recirc again, and the display will show you the current coolant temp.

Do that with the engine cold and you'd expect to see ambient temperature, 5-10c or something, and it should then start to climb as you drive it. You'd expect to see 90c within about 5-10mins of driving. If the thermostat is away, it will climb slowly, will level off at some low temperature, and will fall the faster you drive.

Cheers, I have climate control so will give this a try tomorrow.

 

[martinb!]

right tried this today and it kooks like I may need to change both then. On the climate the display went up pretty slowly to about 48/9 but no higher yet when left on tickover for 10min+ the needle did not move at all.