Help..... temperature low.....Help

**A4donkey** · 09-22-2008 08:07 PM

I've been frustrating about the funky temp gauge, below is the symptoms:

-it keeps between 60 -80 degree C (ten O'clock) for the first 20 minute from cold start (it's summer here up to 34degreeC), when it almost reach 90C, then it drops back to arround 65-70 (ten O'clock)

-after 30minute drive it can stay at 90C.

- I can remember normally it takes 5 minute to reach 90C (12 O'clock)

I have changed the green coolant sensor( 2days ago),top up and bleed the coolant system, but still the same.

She just arround 30K miles, what is the possible cause and fix?

**A4donkey** · 09-23-2008 05:36 AM

I can feel it , there must be something wrong with the thermostat.
Anybody can tell me, the A4 1.8T thermostat is electronic control or mechanical control (drive by heat)?

**gdawg'05a4** · 09-23-2008 05:57 AM

Probably the coolant temp sensor sensor. Easy enough to replace yourself for about $25. There's a write up on A4mods.com

**A4ringedONE8T** · 09-23-2008 06:01 AM

Originally Posted by gdawg'05a4

Probably the coolant temp sensor sensor. Easy enough to replace yourself for about $25. There's a write up on A4mods.com

Yup, green coolant sensor on the back of the head

**gdawg'05a4** · 09-23-2008 06:03 AM

Originally Posted by A4ringedONE8T

Yup, green coolant sensor on the back of the head

Yeah, I had a fun time replacing that. Stupid retaining clip kept falling out of place and not much room to work back there.

**A4ringedONE8T** · 09-23-2008 07:03 AM

Originally Posted by gdawg'05a4

Yeah, I had a fun time replacing that. Stupid retaining clip kept falling out of place and not much room to work back there.

You can thank the SAI system for that!

**gdawg'05a4** · 09-23-2008 07:07 AM

Originally Posted by A4ringedONE8T

You can thank the SAI system for that!

So when I replaced it (mind you, I finished about 12am), I thought it was good to go. Took the car out for a drive to make sure that the coolant temp sensor was ok. About 5 minutes into the ride, the needle starts rising to hot and there's a lot of white smoke coming out from under the car! The clip wasn't in all the way and the sensor popped out a bit spewing coolant out.

Luckily I was next to a 24 hour supermarket and had a large parking lot. Let the car cooled down and then fixed it. It was in the mid 30s outside so my hands were freezing while trying to put the sensor back in.