# Anyone have a DIY to replace Thermostat? A3



## GT1373A (Mar 27, 2002)

I got the infamous P2181 code, and my temperature gauge has gone dead. From everything I read, it's most likely one of 3 things: 1)Temperature sensor, 2)Thermostat, or my water pump. Is that right? Anyway, it seems like the likely culprit in alot of cases is the thermostat, but I can't seem to find a write up for it. Anyone know of any?


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## Elwood (Aug 10, 2001)

Neither the thermostat nor the water pump have any electrical connections so they would not have any effect on the gauge. Start with the sensor.


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## myc526 (Oct 12, 2010)

thello i have the same problem on my 2006 a3 and was the sensor after the new one now working like new. :thumbup::thumbup:


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## GT1373A (Mar 27, 2002)

Cool. I just bought a sensor today, and will try the install.

Thanks


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## GT1373A (Mar 27, 2002)

I've looked everywhere, but I can't find a DIY for changing out the sensor. I just bought the sensor and was hoping to change it out tonight, but I can't seem to find it for the 2.0. If you have a link, let me know. MUCH appreciated.


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## carlosabh (Jan 21, 2003)

there are two coolant temp sensors, one is below the intake manifold (radiator temp sensor) and the other one is below the vacuum pump (battery side of head) you just have to unclip it, pull it, and put the new one in ( it has an O ring which is wise to replace it too) and put the clip back, just do this in the morning with the engine completely cool and you won't loose almost any coolant.


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## GT1373A (Mar 27, 2002)

Doh, two sensors. 50% chance of getting the right one changed out. What are the chances of both being burned out? crap.:banghead:


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## carlosabh (Jan 21, 2003)

check this out : http://wiki.ross-tech.com/wiki/index.php/18613/P2181/008577 maybe this may help you clear this out.


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## GT1373A (Mar 27, 2002)

Ok, so I got the sender installed this weekend and in the process learned how to remove the engine cover, and reset the CEL. Beautiful, right? Well, this morning, the temperature gauge just didn't want to go to the halfway mark like it used to. I figured it was close enough. But at lunch time I did some errands, drove mostly highway, and that temperature gauge did not move from the cold. I haven't gotten a CEL yet, but I am thinking it's coming.


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## mista808 (Apr 30, 2000)

Your t-stat is stuck open.. Exact thing happened to me in my 06 a3... Thought it was the coolant temp sensor so I changed that.. Same thing, gauge stopped working, then cel.. 

At idle, temp gauge would reach running temp ( straight up), but once I started moving the gauge would go left.. Or it would take forever to reach running temp, or it wouldn't even and the gauge would go dead.. 

I couldn't find a diy, but it is kinda hard to do... Did it front mostly the top, had to move the alternator out of the way for better access.. You can buy it from the dealer, I did, costed me like $65 with work discount. Or from ecs tuning.. Good luck..


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## GT1373A (Mar 27, 2002)

Thermostat was my original thought as well, but like the other post said, it's easier and cheaper to try the sensor first. If it works, great, if not, then on to the harder T-stat replacement. I'll try and do this replacement this weekend


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## fune8oi (Aug 12, 2006)

GT1373A said:


> Thermostat was my original thought as well, but like the other post said, it's easier and cheaper to try the sensor first. If it works, great, if not, then on to the harder T-stat replacement. I'll try and do this replacement this weekend


sorry for bringing this one back to life, but did you solve the problem? this happened to mine today  if you have a write up or anything, please let me know! thanks!


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## Chadd (Jan 27, 2003)

Also looking for any tips from those that replaced their thermostats. I think mine is stuck open. Engine is slow to warm up and my gas mileage is dropping fast.


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## obdboost (Feb 27, 2010)

remove the alt to replace the t stat. after that it not to bad, the plastic housing suck to remove. took some force. just take ur time and you'll be good. i can get you tq spec if needed


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## Chadd (Jan 27, 2003)

Thanks. I was looking at http://www.ecstuning.com/Audi-A3-FWD-2.0T/Engine/Cooling/ES252671/

Doesn't look that hard I guess it's just buried. Do you know the difference between the purple and pink antifreeze? I think I'm purple because it's a different color then my b5 that was pink.


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## obdboost (Feb 27, 2010)

it takes pink that the oem cooalnt. if u buy it from the dealer you need to mix it with water


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## Chadd (Jan 27, 2003)

One more thing. I was planning on cleaning intake valves. Would it be much easier to do everything at the same time. The thermostat is priority but if removing the intake would make it easier I'll just do it all at the same time. I've got some rough hesitation when pulling out from stop. 115,000 miles it's probably time.


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## GT1373A (Mar 27, 2002)

I ended up taking it into the shop. The thermostat housing is cheap, but the labor involved in doing it is not for the feint of heart. I think that as a noobie, it would have easily taken me more than 5-6 hours to do it. If you have an extended warranty, check to see if it is covered. Otherwise I think the cost is about about 600 dollars.


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## carlosabh (Jan 21, 2003)

today I replaced the thermostat on my GLI too. What a pain in the ass!!! my back hurts so bad!. I have even replaced the flywheel removing the dsg and subframe and believe me, I think this job is a lot harder!!!
Elsa says that just remove the alternator, take the three coolant hoses and install is the reverse of removal!!! jajajaja just to remove the alternator that is stuck in that area surrounded by hoses tooke me almost two hours, then to take the hoses it was just impossible there isn't any space there to work, I had to take the radiator fan assembly, and the intake hose assembly below the throttle body and even then it was just so difficult to take those hoses off, then remove the thermostat is really tricky it just gets into place in just one form. after gettin it in installing everything else in place was just a tad easier.
Anyways it took me almost 6 hours to complete the job.
Now the car feels a lot more powerful, the old thermostat was opening at 80oC so it was overcooled all the time, heater just blew mild hot not hotter as it should and it was burning gas like a v8, It was doing 16-18mpg at most in city driving. I just checked with VCDS and the engine temp is at a solid 93oC constant temp, I took it for a ride for about 10 miles and it did 28mpg so I am pretty confident that the old thermostat just plain sucked.
6 hours well spent!


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## obdboost (Feb 27, 2010)

yea they suck to do, the dam quick release suck. the hose stick together and are a pain to remove. glad your car is fix


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## ctennyson (Dec 22, 2006)

Bringing this topic back from the dead . I am also experiencing the same symptoms as mentioned in this thread. I have bought the replacement thermostat and trying to figure out where its located. Was there ever a DIY created for this job ?

Cheers


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## quietA3guy (Oct 12, 2007)

I did mine a month ago and this was the best diy i found.
I also used a Bentley manual but it wasn't much help.
The thermostat is located on the engine block behind the alternator.
There is a temp. sensor located in the same place that is much easier to replace while you already have the alternator out.
Tip: there are two screws below and to the right of the throttle body that hold two hard coolant lines in place. I tried loosening them with a t27 bit but ended up striping the heads. they may actually be some size of 12point.


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## dmorrow (Jun 9, 2000)

I also believe I have a thermostat problem (seems to be stuck open). Based on what others are saying I will probably pay someone else to do it.


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## DLV (Dec 10, 2012)

I paid someone else to do it.


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## Willie Gee (Feb 27, 2012)

Any DIY on the Thermostat? I've got the same issue, and I'm not afraid of turing a wrench so long as I know what I'm getting into. I'll replace the sensors first, but I have a sinking feeling it's the thermostat. 

Found one: http://www.youtube.com/watch?v=nZDMexvOlmU


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## Pure.Dope (Mar 26, 2009)

Remove the alternator and throttle pipe. It's not that hard. I promise


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## majic (Mar 10, 2005)

Pure.Dope said:


> Remove the alternator and throttle pipe. It's not that hard. I promise


Ditto... but if you're going for the t-stat... why not just take off the intake manifold and knock out some valve cleaning at the same time


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## everfresh59 (Jul 26, 2010)

What's the average labour time/cost to replace the thermostat? My thermostat is stuck open as well and it's not getting any warmer outside. From what I've read on this thread, my back has no intention of diy-ing this. I just wanna get a rough estimate to make sure I don't get taken for a ride.

Also, do you guys think I'll save a few dollars if I do this while my intake valves/injectors are cleaned? I'm having this work done in 2 weeks, but was wondering if the work can be done at the same time and save me some $$$ for XBox ONE. :laugh:


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## DLV (Dec 10, 2012)

everfresh59 said:


> What's the average labour time/cost to replace the thermostat? My thermostat is stuck open as well and it's not getting any warmer outside. From what I've read on this thread, my back has no intention of diy-ing this. I just wanna get a rough estimate to make sure I don't get taken for a ride.
> 
> Also, do you guys think I'll save a few dollars if I do this while my intake valves/injectors are cleaned? I'm having this work done in 2 weeks, but was wondering if the work can be done at the same time and save me some $$$ for XBox ONE. :laugh:


I paid $400 to have it done. Audi Manhattan wanted $1k so I drove across midtown, over the 59th street bridge and on to a shifty looking repair shop over there in Queens. A year later and all is good. 

I seriously question if valve cleaning is effective at all. And no I'm not trying to induce a rant.


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## dmorrow (Jun 9, 2000)

DLV said:


> I seriously question if valve cleaning is effective at all. And no I'm not trying to induce a rant.


What does this mean? Are you questioning the need to do it or whether it temporarily or permanently solves an issue?


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