So I went to replace my failing ECT this morning. I ordered the blue one from ECS for my 99.5 2.8L.

I removed the connecter confirming that the original was blue. Before I removed the original, thankfully I opened the box. Much to my surprise, the replacement was green. The box is labeled as the blue one. Is this green a replacement for the blue or was it boxed incorrectly? What is the difference in the two?

 

nothing. same thing happened to me. the green one they advertise is a circle instead of a square. it will work. it solved my problems. i even contacted the support so its all good.

 

Where is this installed?
I ask because I have a 2001 S4 with no heater!
I flushed the core have good flow no problems, no air lock.
Attached a pipe to one of the heater hoses blowed down it and had good flow of antifreeze out, attached it to heater so it would flow thrrough, no problem there.

But with engine running & hot I can remove the heater hoses and have no flow, I'd expect a good gush from the engine but nothing!.
Engine temp it good, dead centre of the gauge, no overheat issues, no leaking fluid.
Am now thinking there is a valve that regulates the flow from the engine side to the heater core? is there? is it just open flow hose?
Confused because of the ability to blow through system etc.
any ideas? anyone...

 

if your engine temp is fine this thread will not help but i bet someone can chime in. sounds like a clogged heater core.did you flush the core itself?

 

I had the same query when I ordered mine, called tech support and they confirmed just what jonesbonesjones said. Don't worry about the color.

 

So I went ahead and replaced the sensor with the green one. I still get the same fluctuation of the temp gauge though. I had figured it had to be the sensor rather than the thermostat since it doesn't overheat and kicks out plenty of heat in the cabin. What gives?

 

bshusted,

Did you fix your fluctuating temp guage? If so what was the problem?

 

After spending more time with the car I did notice that while driving slowly, the temp comes up to normal. Driving at a higher speed brings the gauge back down. I'm willing to assume that the sensor I replaced was still good and that my issue is with a stuck open thermostat.

Since the thermostat on the V6 is not in a friendly place, I have put off replacing the thermostat until it is warmer out and I have more time. As far as I know the only ill effect of driving the car in its current state is worse gas mileage. I have some vacation time next month and plan to tackle the t-stat only since my timing belt only has 10k on it.

What are your symptoms?

 

I have an 04 A4 with the 1.8T, the only problem I see is the fluctuating water temp guage. Heat is great, runs great and no fault codes.

 

If you have an '04 you may want to check in the B6 section.

Even on the 1.8T, the temp sensor is going to be easier to change than the t-stat. I would start there and see if it solves your problem. When you order a new sensor check your old one for the color, or have your VIN ready so that you get the correct flavor.

May want to check this for more info on the install. http://www.audiworld.com/tech/eng47.shtml