Seem to be running cool. What to do?

[stapo69]

Just recently I've noticed my car doesn't seem to be getting anywhere near as warm as it used to be.

The coolant only gets to about 75 degrees, reading from my liquid display not just the dash guage, and the same for the oil, barely reaches the 80 degree mark on the guage.

I've searched and searched and am confusing myself more and more. I'm pretty sure they both used to read around the 90 degree mark after the same amount of driving.

What advice can you give? temp sensors? Thermostat? What to replace? Don't wanna just start replacing parts willy nilly as I'm really not sure what to do.

Help!!!!!!

[AudiSportB5S4]

Does your coolant gauge sit in the middle? or below that after 15-20 minutes... If so your thermostat may be stuck open. It would happen to me on long drives after a while my car would almost be dead cold again! Fixed that with the t-belt change/t stat/ waterpump etc

[s4nicetry]

I'd start with looking at coolant temp sensor as it's cheap and easy to get to, and I would think probably the likely culprit. If not that it could be faulty t-stat, does your heat work fine in the car?

[stapo69]

Heater seems to get warm enough inside the car. Coolant guage sits around the 70 to 80 degree mark, doesn't get up to the middle 90 degree mark now. I've got a thermostat on order but just discovered how it needs fitting! I'll get a coolant temp sensor ordered too. Where is this located on the car?

[stamps]

I have the same issue, in the summer (warm weather) the car will work in the operating temp area but now it is 40 and below it sits in the lower third of the gauge. the oil has the same effect, is warm in warm weather and stays cold in cold weather. Both are magnified during highway driving. the car actually gets warmer after sitting a few min after a 3 hour highway trip.

[s4nicetry]

Location of coolant temp sensor...
http://forums.audiworld.com/s4/msgs/2388071.phtml

[stapo69]

Thanks for that. I'm gonna replace the sender and see what happens, if it doesn't work I'm gonna have to rip the front end off and tackle the thermostat. Anyone know where the oil temp sender/sensor is?

[stapo69]

Just for those searching and want a result, I changed the thermostat after a long PITA day in the garage and it solved the temp issue, she now gets up to the more reasonable temps and a lot quicker.

[CONTROL ONE]

how difficult was it to replace the tstat?

[AudiSportB5S4]

Thanks for that. I'm gonna replace the sender and see what happens, if it doesn't work I'm gonna have to rip the front end off and tackle the thermostat. Anyone know where the oil temp sender/sensor is?

the oil temp sender is directly attached to the lower oil pan. can't miss it

[stapo69]

how difficult was it to replace the tstat?

A long job. Basically the same as a cam belt change with just another cover off to get to the thermostat as the belt runs across the face of the cover.

Basically bumper off, whole front end off into service position, drain coolant, remove viscous fan, ribbed belt, tensioners and a couple of other bits, then covers off, remove cambelt, then cover to thermostat, and then all back, took about 7 hours.I replaced wate pump, and all belts at the same time as it made sense. I used Audi workshop manual and this for the pictures, a good guide to doing cambelt:

http://www.audi-forums.com/b5-forum/...-belt-diy.html

Time consuming mainly as a lot has to come off, and not for the faint hearted if you don't like cambelt work, but saying that we used no cam lock tools as the gears were all to hard move by hand anyway, just gotta be careful when refitting that it goes back in the same place, mark everything!

[haus4]

Did the t-stat fix your oil temp being low as well? Just curious.

[stapo69]

Yeah, all running good now, coolant gets straight up to 90 and stays spot on, the oil gets up to around 90 when cruising, 100+ when giving it some. Way up on the 70 it stayed at before.