Hey All, Im new to the forum but been an audi owner for a few years. After the expensive replacement of the water pump on our 98 A6, we traded in when my wife fell in love with a red 01 TT Quattro Convertible. Its been great until the beginning of our first winter with it.

Problem #1

After the temperatures dropped below freezing, the dashboard cluster flashes and the gauges constantly reset. But radio and everything else works just fine. After about 5mins of running, the flashing frequency slows down and eventually stops. However, we have had a few days above the 50f mark, and still no change. Along with this the gas gauge no longer shows the proper reading, full is well above the full line, and empty is about a quater tank, but it never moves while running. For example, if we were to go on a long trip starting with a full tank, it would always show full, until we stopped the car and restarted it. Then it might move. The digital readout of est miles left is correct. Any thoughts on this?

Problem #2 and Major Issue

In the fall of last year the car overheated a couple of times, mainly when hot out and when we were doing alot of stop and start traffic. We just turned turned the heater on and got out of traffic, it cooled down just fine. Then this never happened over the winter. Yesterday my wife tells me that her cars temp gauge was completely at the Hot side. Luckily she was home. However, it was not warm enough to have the top down yet, . So today I just did a few checks on fluids and such, everything seemed good. Let it idle in the driveway for about 10min, and it was ready to overheat. Noticed that the fan behind the radiator was not running. I have always thought that the fan should run when the car is idle and beginning to warm up, and usually shuts off when moving at any decent speed. But I have read on this forum that the electric fan motors will only run when the a/c is on. So as a test, I started the car with a cold engine (car says its 60 degrees f outside), cranked the a/c to full blast and let it idle, about 2 mins later I was at the full hot mark. The fan NEVER kicked on. Turned the car off and I can hear the water pump still running, so I am pretty sure that is not the problem. I think its just a bad fan motor, or something along those lines. Any help on how to test and find this out?

 

The clusters are a high failure rate item on the TT, there was a recall on them (now expired).

Typically the temp gauges and fuel gauges fail along with all sorts of other weird behavior.

BB manufacturing and Modulemaster will rebuild the clusters if you can remove it from the car and send it in. The car alarm / key/ immobilizer is linked to the cluster so by fixing your unit you eliminate having to go to the dealer for recoding.

The fan should run when the AC is on, if it doesn't you could have blown a fuse, the fan switch or fan is bad. The fuses are on top of the battery. The fan switch is in the radiator on the engine side drivers side.

Has your car ever had the timing belt replaced? If not the plastic pumps can sometimes cause this. They break and you get uneven temperatures in the cooling system as the coolant doesn't circulate.


I would run a Vag.com test to check the cluster first, then check the gauge temp is actually correct and you really are overheating. Thermostat is 89C, so you should water temp about that. Anything over that is overheating.

 

AudiMick,

Thanks for the detailed response!! I really appreciate it. I also own a Nissan Titan and a Honda CBR 600RR, and when asking for help in those arenas on other forums, people are usually rude and make newbies feel like they shouldnt be asking questions. Thanks alot for taking the time to help me.

Ok, so I have ordered my vag-com cable and should be here soon. Also, I have a candy thermometer in the resevoir, is this a good place to test the temp of the coolant? Right now the temp guage reads full hot after about 30mins of idle with the a/c on full blast. The temp of the coolant in the resevoir is approx 85-90C. From what you have said this is about normal. Until I get my vag-com cable in do you think its prolly safe to drive the 15min commute to work?

Thanks!

 

Also, I failed to mention that it is 75f outside, and the lower passenger side fan IS running. It has been an hour now and the thermometer is at 95C. Doest not look like it is going to climb any more.

 

You can use the HVAC to monitor coolant temps. Use the info at this link https://www.audiworld.com/tech/int6.shtml BUT monitor coolant temp at block 49 on our cars. The second engine fan does not come on until 105C unless you have the AC on . With AC on it runs regardless. Good luck!

 

It sounds like you are maybe not overheating as J Patterson said the second fan doesn't cut in until 105C and your only getting to 95C.

Looking more like a cluster problem which considering all the other problems with it (and AUDI's history with this assembly) seems very possible.

 

Also, you may want to check the fuses on top of the battery under the black hinged panel. There are three green fuses. Check for blown/over heated fuses. Also, check the wiring for corrosion. Poor resistance through those wires can cause all sorts of gauge, fan and general HVAC nightmares.