black_bullet6

Ok I dont know if I'm just being overly paranoid but I've noticed lately that everytime i start my car the temp gauge always goes to the middle. Even when I start it in the morning itll go to the middle. I remember it would take a little bit for it to get up there. When I turn it off it goes down. Now its gotten warmer outside but that just seems strange to me. any thoughts?

black_bullet6

any ideas, thoughts....noob comments?

turbo510

Could be a failed temp sensor. Usually pretty easy to change.

lyleswk

Let's be clear. In the morning immediately after you start, it should be all the way to the left on "C". It should take a few minutes to "warm-up" and then yes, it should be in the middle. Mine sits just above the center mark. The ECU controls the amount of coolant flowing into the engine to regulate this at that middle mark regardless of outside air temperature, i.e. in the winter, it let's less coolant through than in the summer. The only difference you should see between winter and summer is the amount of time it takes for it to go from "C" to the mid-point.

If it starts at the mid-point in the morning, then yes you have a problem that as turbo 510 notes is probably the sensor.

fg_carz18

X2 It will take at least 3 miles before it starts moving to the middle(thats if coming from a cold start). Well at least for mine it goes a line before the middle line after driving for 5 mins or so.

Halo549

I have started seeing a simalar problem.

After starting mine is on the C. Then after 5 minutes or so it moves to
just above the middle. If I watch it while driving about 15 minutes
to 1 to 2 hours on and off it goes closer to the C about the first line.

Any thoughts?

AudiCO

I had to change the coolant temp sensor on my '02 a few months ago. The gauge was acting erratically in that it would suddenly drop off to C while the engine was warm. I wouldn't say it was an 'easy' fix; not really difficult but more just a pain in the *** working by feel stretched over the engine to get that retaining clip on without breaking it.

black_bullet6

Sorry for such a delayred responce was on vacation, yea to be clear when i start it in the morn from a cold start it goes straight to the middle which i kno is not normal. it used to take a few minutes of driving to get it there like everyone else. ill try checking the temp sensor. thanks for all the replies

lyleswk

I would start with the sensor on this as well, but if that doesn't solve it, you may have a faulty thermostat. The thermostat in our cars is electronically controlled by the ECU via inputs from the aforementioned temp sensor in the coolant flange (green sensor) as well as from inputs from a coolant sensor at the radiator (black sensor), i.e. it varies how much coolant goes into the motor by controling the valve in the thermostat depending on driving conditions. As I said, start with the easy stuff, green sensor followed by black sensor and if that doesn't solve it, you may be looking at a thermostat.

Halo549

Purchaced the green Temp sensor from the dealer, made sure to get the right one. Having trouble locating where it goes. I know its on the engine by the firewall on the passenger side. Soo much in the way can't realy see where it goes. I looked at the Tech part of this page and they show an older model A4. Newer models have lots of engine part covers.