Been lurking these forums, since i got my high mileage 2001 TT Coupe. Read almost every overheating thread here and i just changed the thermostat based on reading some threads...

I flushed the coolant and replaced with G12 along with a new OEM thermostat (PIA btw)...

Been using 49C to monitor cooling temp along with Torque (on Android & bluetooth adapter)...

After changing the therm/coolant... car has been running a little cooler than before. However, when i stop the car for a long amount of time in idle, i get up to about 104-107 deg C. After running on the freeway or when the car is moving, temp is around 90-94C.

Noticed that my rad fan had turned on AFTER the car was off, but did not turn on when i popped the hood with engine running (~98C to 106C).

Checked coolant temp with engine off and rad fan on (temp ~108C).

Is this just a matter of replacing the coolant temp switch?? (i already have a green top sensor and don't think it's the water pump as many have stated and in the faq).

 

More info:
- Rad Fan and AC condenser fan turn on when AC is on
- When fuse 16 is pulled on driver side panel, both fans come on

attached is what i used for my honda in which i replaced the ECT switch... is the same troubleshooting accurate for an audi?

 

talked w/ an independent vw/audi repair shop just to get their take...

- said it is most likely the fan switch on radiator
- questioned that when i turn off the engine, fan kicks on--said there's an after-run sensor that kicks on the fan--haven't hear of this "additional" fan switch before, but i'll have to check the Bentley manual
- said that the fan control module is okay, since the fans kick on in A/C mode
- quoted $145 including parts to replace switch (if that is the culprit)

How hard/easy is it to replace the switch? Bentley says i need to remove the front bumper assy for adequate access.

Looking down at the switch, i tend to agree, but has anyone replaced this w/o removing the bumper?

 

Not sure if you got an answer to this or figured it out but i was wondering the same thing. I am about to get the part....5 bucks through ecs tuning. I have been told that I need to take the bumper off for many different things but I have never actually had to. My fans would only work if i turned the heat on as well so we are in the same boat it appears.

 

have you tried bleeding air out of the coolant?

park it on incline, get heavy duty gloves and pull the top radiator hose off while running, have somone fill your res at the same time. once steam is gone and have constant flow put the hose back on.

you should vag your fans first to verify there faulty.

 

I haven't tried that, but i will once i replace the switch. Went ahead and ordered the switch from AudiHendersonparts for $43 shipped. ECS had it for $5, but it was aftermarket (don't know if the brand is good or not).

Still unsure if i can adequately remove the switch w/o removing the bumper. Also, i'm unfamiliar with removing audi connectors and when i reached down there, the connector was very stiff and i don't know if i can remove the old switch all that carefully.

 

typically MTC that is shown is just as consistant as any Meyele FEBI URO Mann

all
good

 

Its my understanding your fan should NOT be kicking of after you park the vehicle. If its turning on then its a fail safe for your auxiliary water pump not turning on to cool your turbo. You might need to replace your water pump and also if your temp drops while your in motion but goes higher when your at a light its your radiator fan. Plain and simple. The temp drops because the air coming into your engine bay is cooling the engine. It actually says this in your owners manual . Quick and easy way to test this is to disconnect the radiator control sensor harness and touch 2 and 3 together I'm referring to the connectors inside the actual harness...link them with some wiring if your fan goes well good for you!! then its not your fan and you just have to replace your radiator control sensor. Of course it could also be your radiator fan module. But yeah try it out.

 

From reading some posts here and the Bentley manual, the 1.8 AWP does not have an after-run coolant feature; only the 225 and maybe the 3.2.

The manual does state that the fans can come on at any time; my Honda does the same thing in where it turns on the fan after the engine is off. You may be on to something though in that it could be a fault of some sort if the fans aren't intended to come on at all after the engine is off.

I do not believe it's the fan module, as the fans turn on when in A/C mode and when Fuse 16 is pulled, fans come on as well.

I'm about to call around locally... Napa/Altrom parts (~$20) seem to be of high quality, so i may give that a shot. OE Audi Part from dealer will take a few days to get in and will cost >$55 here in the bay area.

 

Found out that the switch is 22mm... any suggestions on replacement tool to use? Crow's foot + Universal Joint work? Angled box wrench? (Still wondering if i need to remove the bumper for better access or not)...