satch69

I did a quick search and didn't find the particular problem. Maybe someone can point me to a relevant tech article / thread?

The vehicle is a 1999 a4 2.8 5-spd quattro with 130k miles.

The problem is that as it's gotten colder, my coolant temperature gauge barely rises. Same with the oil temp gauge. Even after 10+ minutes of normal city driving.

Heat works (takes about 5 minutes to blow hot air). External temp gauge seems accurate.

During the summer (when I first got the car) the coolant temp rarely exceeded 1/4. However I do remember seeing it at the 1/2 point on occasion.

Just to clarify, now, the coolant temp moves, but imperceptibly. In the last couple of months, I don't remember it moving more than a couple mm.

What should I do? many thanks in advance

ianbis

resources/tech articles/Engine/coolant temp sensor replacement by Kris Hansen 2007

satch69

thanks! any idea if this improves my current mileage of 17mpg city?

ianbis

it might that signal goes to the ECU + IIRC is used to determine the running parameters so to speak

velosouljah

if you leave your car idling for several minutes especially after 10+ mile drive will the coolant temp gauge go to the middle? Just wonder if your thermostat is stuck open too or if that could be the problem. FWIW, I'd replace both CTS as already mentioned and the thermostat if they are still original at 130K not to mention a bazillion other things.

satch69

no. Used to happen in summer. Maybe it failed during my short ownership? Will replace both

velosouljah

I hope the timing belt, h2o pump, etc. are not still the original ones at 130K?

satch69

Owner says they were replaced, as do the maintenance stickers within engine bay.