jacobhoupt

Few things I've noticed since it got cold here...

First, I'm getting the worst gas mileage I've ever had out of my 97 A6q (15-16mpg).

Second, my heater doesn't work.

Third, engine temperature gauge shows my car within the bottom bold lines on temp.

Channel 51 on the CC module is reading 9. At all times.

So the question I pose to the Audi gurus...Would the ECT cause all this?

And if so, how do I change the dang thing?

Thanks and much appreciation are in order to those who help me. The rest of you can go jump in the lake.

-jacobhoupt
me@jacobhoupt.com

1997 A6 Quattro Sedan

jacobhoupt

Channel 51 is now working properly. I appear to be getting codes 11.7, 15.7, and 8.5.

8.5 means the motor is cycling....I don't understand that. Anyone have any ideas?

kday

I don't know the details of the V6 cooling system, but I can tell you this about the I5 system which is most likely the same: the dash gauge, climate control, and ECU all have their own coolant temperature sensors.

The other thing is that the coolant temperature is mechanically regulated by the thermostat, and is totally independent of the sensors. The fact that you have multiple indications (1,2,3) of low coolant temperature suggests that it is not a bad sensor giving you false readings.

Unfortunately I don't think changing the V6 thermostat is as easy as it is on the 5 cyl.

austinado16

I've seen this twice now on the last 2 sedans that I've purchased.

The first one was staying so cold it was turning on the check engine light and wouldn't pass smog inspection at the tailpipe due to the increased emmissions. Put a $15 "BTT" OE t-stat in it and it cured the problems.

This car I'm doing right now isn't throughing the MIL light, but 2 days ago I drove it 13mi on the freeway and it never got out of the cold bar area of the temp gauge.

Here's the good news:
1) The 87*C BTT t-stats are cheap
2) The replacement is fairly easy:
Take off the plastic covers on the engine like you were doing a timing belt job.

On the right side of the engine, remove the two 6mm bolts that hold the big long t-stat housing to the front of the right head/block area. Hint: that right side front radiator hose is attached to it.

The housing can be snaked out from behind the timing belt (or so I've been told).

When it's all back together, just make sure you do a good job of burping all the air out of the cooling system.

Problem solved.

austinado16

Replaced my t-stat today. Took about 30min. Cured problem & car actaully runs better!

1chancey

wonderful ... this sounds similar.

i changed the thermostat last weekend - and assumed that i had preformed a proper flush on the radiator. but no on thursday, my usual 10 miles a day turned into almost 20 before the light for the water level started flashing aaaagain just as if i had never replaced thermostat. what a beautiful sight it was -> lunch time and and awaiting a red light when the smoke started in. i made it to the shopping center where i simply left it to cool.
what gets me .. is the water temp gage still didn't even make it to 1/2 way. *humps shoulders*


i would love to have a better idea of where to start. im one step away from changing the sensors (radiator temp - mass air - etc).

i read that a bad radiator temp sensor would cause the water to boil and constrict the flow ... ??

also, after receiving some advice on bleeding the system ... i began with step one. finding the bleders ... and well, unfortunately i've only been able to locate one.

pleeeeaase help - i would greatly appreciate it :}