Cooling System not working, I'm stumped, and frozen

[GetSmurfed]

I have a 2003 1.8t AWM, and this morning the Engine stayed cold, and only blew cold air...


What has happened so far...

1 Water pump failed in 2007, and was replaced by the dealer under warranty

2 Bought the car in early 2007, and noticed Cabin Heating and Cooling were not as good as my old MK4 Jetta, just accepted it...

3 Summer 2009 A/C started to not be effective, would only blow air 12F lower than outside Temp, put this off to deal with later

4 Engine Temp started jumping from 90 to 190 eraticly, but mostly staying at 90F. Started getting 'Implausible' Codes from the cooling system that were putting the car into Limp Mode.

5 2010 Installed a new Cabin Filter and Coolant Temp Sensor, which fixed the engine Temp enough for me to see that the car took a long time to warm up. Temp would fluctuate with driving conditions, making me think it must be the Thermostat. Still in Limp Mode

6 In Nov 2010 I had the Timing Belt done, put in a new(proper) water pump, and new Thermostat. Car worked properly for 2 weeks, No Limp, cabin heating was ok.

7 Now... Engine does not get to Temp, at all, only occasionally I see the Temp Guage rise a tiny bit then fall. Car is in Limp Mode all the time (during warmup ~1 min, it boosts properly)

This Morning it was 20F outside, my 40 minute, 20 mile drive to work, only got the Cabin temperature up to 50F. It must have been me warming the Cabin up, because the only thing coming out of the vents was cool air.

Once at work I popped the hood and felt some hoses... Top Rad Hose felt warm ~100F, Bottom Rad Hose to Thermostat felt lukewarm ~60F

I'm still cold, and dreading driving later, since is still below freezing out!


The only thing I can think of, is maybe some crap has jammed the Thermostat open, but the old Thermostat had the same symptom, but no crap in it...

[ScottPassat2.8]

climatronic or dials?
did you feel the heater core hoses, they are under the rain tray right in the middle of the car.
they should both be hot.

[GetSmurfed]

Dials,

I didn't feel the Heater Core Hoses, though all other coolant hoses were Lukewarm

[JayTheSnork]

sounds like the new thermostat has failed.

[50pascals]

I doubt climatronic has anything to do with it. If the upper hose isn't hot, then the thermostat is stuck open.

[PZ]

No Climatronic on a 1.8T in the US that I have ever seen. I suspect the new Tstat has also failed.

[rome_rod]

climatronic or dials?
did you feel the heater hoses, they are under the rain tray right in the middle of the car.
they should both be hot.

Dials,

I didn't feel the Heater Core Hoses, though all other coolant hoses were Lukewarm

I agree. It is important to do this step first as it will help in correct identification of the cause. If both of the heater hoses are hot to touch then it is working fine and the issue may be with the thermostat. Otherwise, there is blockage or presence of air in the heater core.

[GetSmurfed]

been quite busy lately, but I did find the issue...

it was the thermostat, the middle bit came out of the hole in the bottom, so basically the moving part was turned sideways....

Thanks