Thermostat or Coolant Temp. Sensor?

[gtsingh91]

So I have an AWM with about 189k on it. It runs beautifully and strong. No CEL or stored codes in vagcom. However, the temp gauge takes forever to come up to the middle. Like after 25-35 minutes of highway driving, it's only at the second or third mark between halfway and Cold. On shorter trips, it doesn't even move. Heat and AC works all the time (idle and cruising). Coolant level is always fine in the reservoir. Like I said no drivability issues nor is my gas mileage bad. Do I have a bad thermostat or coolant temperature sensor? I'd rather not just throw parts at something and hope it fixes it. Thanks

[CoyneJ]

Probably your thermostat is stuck open, sensor is fine since you gauge moves but sensors are pretty cheap and come with a coolant flushes kits

[clause$]

Same as me. AWM, 175k. I have a new thermostat, just need to put it in.

[CoyneJ]

Lol awm 200k squad soon? I got 216k

[gtsingh91]

Just ordered a new OEM VW thermostat with o-ring (same PN as ours). I'll give that a shot. My only concern is that I don't have vagcom so I wouldn't be able to do a throttle body alignment after I remove it from the intake manifold.

[CoyneJ]

I never removed my intake while doing the thermostat, it was a bitch but is doable

[gtsingh91]

I never removed my intake while doing the thermostat, it was a bitch but is doable

You mean you didn't remove the hose from the IC to IM? Or you just didn't remove the throttle body from the IM? I don't see how it's possible to do without removing the IC to IM hose lol

[CoyneJ]

I only removed the hose and I got it out

[kwnk]

I was able to change the thermostat when I had the alternator out (had to replace the alternator and I figured I'd do the thermostat as well)

[freekonwheelz1]

I had the same problem. When I pulled my motor I replaced my thermostat and it fixed the issue. Lucky for us the factory thermostat sticks open instead of closed. I liked how it stayed colder. Boosted cars+heat=less fun lol

Sent from my HTC One M9 using Audizine mobile app

[RENOxDECEPTION]

wrong thread....

[gtsingh91]

I got my thermostat and o-ring today but noticed something weird. Is the O-ring supposed to be larger than the thermostat? I thought the O-ring is supposed to fit over the edge of thermostat and go in as one piece but that wouldn't really be possible. I ordered part number 038121119B for the O-ring and 050121113C for the thermostat, as per GenuineAudiParts.com.

My car is a 2001 AWM A4 1.8T.

[ElSabio182]

The o-ring sits on the flange of the T-stat housing (the plastic tube), which is what the thermostat sits inside of (if I recall correctly).

As seen here (https://youtu.be/K5dickQb8HM?t=5m26s) 5:25 if that doesn't load correctly.

[gtsingh91]

^^ Thanks, that's funny I actually watched that video but totally missed that part. But that makes sense. Never seen a thermostat without the o-ring not attached to it (mostly work on Japanese cars).

[Mattr567]

Yea my t-stat went bad at 123k, 99 AEB. The gauge never moved even on longer trips. Really took a lot out of the performance. Reluctancy to rev.

Bought it from the original owner that way actually so who knows how long it's been stuck open. A year or two possibly.

[gtsingh91]

Took a look at my thermostat housing today to see what kind of tools i'll need for the job and in the Passat AWM DIY on youtube, it shows him using a 10mm swivel socket, but my thermostat housing (01 AWM) looks like it has two round hex screws holding it in. Any thoughts?

[freekonwheelz1]

these are what mine is heald on with. there is a top bolt and bottom bolt and the center is a 5 mm allen and the outside is a 10 mm socket.