[Chef Nails]

The heater in my 02 Turbo S won't get warm at all. I mean it's barely tepid. I researched the issue on the site here and determined it was most likely a thermostat failure, probably a partially opening thermostat. I got a new thermostat, housing and also picked up a new coolant temp sensor just to be safe. I drained the coolant, replaced the sensor and the thermostat and refilled the coolant, being careful to purge the system of air. I've been through the procedure a number of times on other vehicles so the approach isn't new to me. And after running the engine for over twenty minutes the heater is still barely warm. I can feel the lower rad hose get hot when the thermostat opens, but the fans never kick on and the heat just won't get hot. The car never runs hot. I also checked the 40 amp fuse to the fans and it is fine.

So, any ideas or input?

Also, on a related note I have to say that I am impressed with the design of the cooling system. When I drained the coolant I was expecting it to be dirtied but it is spotless. No discoloration at all. This is the first time I have worked with the cooling system since I bought the car almost two years ago, so even if the previous owner changed the coolant right before I bought it, it still looks very clean given the amount of use.

 

[VDubYah]

I can only think of 2 reasons at this point.
1. problem with coolent flow thru the heater core.
2. The dreaded blend door issue with no foam left on it, thus mixing cold air with heated air.

 

[Chef Nails]

Thank you, although I am not aware of the dreaded blend door issue. I imagine it means a lot of disassembling to get to? Also I tested the old thermostat in a pot of water and it fully opened and closed three or four times, so it didn't really need to be changed, although I don't mind since replacing it with a new one can only increase the longevity of the cooling system, and I have a spare thermostat now.

 

[VDubYah]

The foam comes off of the blend door and blows little pieces of
blck sticky foam out of the vents.

It's a big pain to fix as you have to disasemble the whole dash to get to it.

You might want to check and make sure the heater control is moving the lever for the heat control. There is a plastic bushing that gets displaced and causes trouble.
D2Beetle did a great dyi to show how its done.

https://www.google.com/url?q=http:/...ds-cse&usg=AFQjCNGEdvRKTueIvE2wzqWrPcOFWzD6RQ