Audi TT Forum banner
1 - 16 of 16 Posts

·
Registered
Joined
·
30 Posts
Discussion Starter · #1 ·
Afternoon all I have a few questions about the car that I think are related to the engine temp sensor...
When starting the car from cold all seems fine. But once I have stopped and turned the engine off, come back to the car and start it, the engine goes to stall
When driving the water temp gauge now doesn't always hit 90 even after motorway driving
Engine feels very laggy, almost like a boost leak at times

If I were to replace the sensor how do I know which one to buy? Is my car bam or apx? I looked on gsf and they list a sensor with the same details but at two different prices?? My car is a W reg, 225 model

Thanks in advance,

Dan
 

·
Registered
Joined
·
1,214 Posts
To find out your engine type take the top cover off the engine and look at the front left side the is a metal bit of the head showing with your engine type on it in this photo its near the top left next to the two pipes "BAM" in my case upside down
charge pipe removed in this photo !

for a good guide on replacing the sensor see here (Thanks WAK) mine has failed twice so far so I keep a spare as they are cheap and easy to replace http://www.wak-tt.com/tempsensor/tempsensor.htm
in your case it sounds like the thermostat MAY be faulty as well but the temp sensor is the cheap easy fix so start there first !
check out waks site as he has a TON of handy information and tips for the New & Old TT owner 8)

http://www.wak-tt.com/
 

·
Registered
Joined
·
2,795 Posts
Hi mate

The car not getting up to 90deg will very likely be a faulty thermostat , it is a very common problem.... stat is pretty cheap just a little awkward to change. Will need new G12 coolant as well. Might as well change the temp sensor while your at it.

To confirm it is the stat and not a faulty dash pod do the 49c trick on the climate control..

The car should not be stalling after a restart , the above items being faulty would not cause this either. As you say it seems laggy i would expect a boost leak as that would cause the car to stall... have a good look at all hoses ( quite a few lol ) and check for splits and loose connections etc

Your car will be an APX as it is W reg unless it has had an engine change.

Get the bits from Eurocarparts as you get a 25% discount being a forum member :)
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #4 ·
Thanks guys, have looked at that bit on WAKs website and my car does literally everything it says on there!!! I also dont hear the fans running or coming on, i assume because the engine is not getting the right reading from the ecu and sensors. Will driving the car like this do it long term damage? I plan to get things sorted but it obviously will take a few days to get parts etc

Cheers
 

·
Administrator
2001 Amulet Red 225 coupe.Owned from new as well as a Nurburg VXR & an XR3, all from new.
Joined
·
95,341 Posts
Hi Dan, As above really looks like 2 probs, but check actual coolant temp by using Code 49c on CC, click link follow instructions.
Temp sensor has 2 outputs & it appears one may be telling the ECU the engine is colder than it actually is, which is causing the hot starting prob & stalling.Replace sensor cheap & easy.. As said APX for 99 reg, but reg doc will tell you.
Edit, short term will not cause prob, but engine will be running rich,so not recommended long term.
Hoggy. :D
 

·
Registered
Joined
·
278 Posts
Is there a guide anywhere to replace the thermostat? My car always gets to 75 deg and occasionally gets to 90. The climate trick corresponds to the dash pod temp so looks like I have a dodgy thermostat?
 

·
Administrator
2001 Amulet Red 225 coupe.Owned from new as well as a Nurburg VXR & an XR3, all from new.
Joined
·
95,341 Posts
olibb said:
Is there a guide anywhere to replace the thermostat? My car always gets to 75 deg and occasionally gets to 90. The climate trick corresponds to the dash pod temp so looks like I have a dodgy thermostat?
Hi, this may help. From Mk1 K.B.
viewtopic.php?t=56316
Hoggy. :D
 

·
Registered
Joined
·
2,884 Posts
When starting the car from cold all seems fine. But once I have stopped and turned the engine off, come back to the car and start it, the engine goes to stall

Mine does exactly the same but in intermittent and the engine temp gauge always reads 90 degrees rock solid, advice please.
 

·
Administrator
2001 Amulet Red 225 coupe.Owned from new as well as a Nurburg VXR & an XR3, all from new.
Joined
·
95,341 Posts
Hi Bob, As I said above, temp sensor has 2 outputs, 1 tells the ecu the temp, the gauge can read correctly, but ecu is being told the wrong temp, replace the sensor, cheap & easy, & all in the above posts.
Hoggy. :D
 

·
Registered
Joined
·
1,214 Posts
Had exactly that happen on my last sensor falure car temp gauge read normal but fans came on and big
red warning light on the dash saying overheating even though I had just started the car after it had stood all
night so I smelled a rat straght away :mrgreen: sensor replaced problem gone :p
 

·
Registered
Joined
·
416 Posts
Hay guys just seen this today I've done 290 miles to Newquay and the needle kept dropping to 70c then back up to 90c had the cc on and that read 90c all the time. Just looked at the list and it's 51c not 49c thats 49 Malfunction counter for speedometer (vehicle speed) signal could my proble also be the temp sensor? Also where is it located. Sorry for the thread hog
 

·
Administrator
2001 Amulet Red 225 coupe.Owned from new as well as a Nurburg VXR & an XR3, all from new.
Joined
·
95,341 Posts
Hi Jamie, Coolant temp is Code 49c, forget code 51c (engine temp). Code 49c is the one to check..
Appears to be thermostat prob to me.
Hoggy. :D
 

·
Registered
Joined
·
416 Posts
Thanks hoggy the list is on Audi world so just followed that. I hate getin faulse info will use 49c on the way home and get a new sensor and thermo. Do u think it should be ok for the 290 mile back home. Did seem a bit leggy to. I've not got a boost leak looked a few times
 

·
Administrator
2001 Amulet Red 225 coupe.Owned from new as well as a Nurburg VXR & an XR3, all from new.
Joined
·
95,341 Posts
Hi Jamie, Believe the TTF info first. I try hard not to give duff gen.
If TT is running cold, if may be running a bit rich, but won't cause any probs short term, just lighten your wallet sooner.
Hoggy. :D
 

·
Registered
Joined
·
416 Posts

·
Administrator
2001 Amulet Red 225 coupe.Owned from new as well as a Nurburg VXR & an XR3, all from new.
Joined
·
95,341 Posts
Hi Jamie, Yes I have seen that before, They are wrong any way in relation to coolant temp. This is the one to use.
Hoggy. :D
 
1 - 16 of 16 Posts
Top