View Full Version : engine still overheats after timing belt change

09-30-2008, 12:22 PM
Hi all, I have a 97 audi a4 1.8t quattro with auto tranny. Mods so far are apr chip, forge dv, apr turbo inlet pipe. Car has 133000km.

Last weekend my buddy and i changed the timing belt on my car with the ECS ultimate timing belt kit (so it includes new thermostat and waterpump). We also use petosin coolant. We put on a front mount intercooler too. Before the timing belt job, my car overheats easily. But after the job, it still overheats. What else do you guys think it could be? Thanks for any input.

09-30-2008, 12:26 PM
unless petosin is a codeword for G12, then it may be your coolant type... also are you leaking any coolant?

09-30-2008, 12:39 PM
Yeah, it's a G12 coolant. No coolant leak at all.

10-05-2008, 06:02 PM
does your coolant level stay constant? If it's circulating properly and also staying full, there's always the possibility that the coolant temp sensor is gone. It's the small blue or green sensor at the back of the head that has the heater core going into it. It's only like $10 online so it may be worth a try.

10-05-2008, 06:07 PM
'97 It should be blue with a square black connector.

Check the flow and heat dissipation of your radiator. You should see 35-40*F difference between the inlet and outlet temps.

Also, make sure your fans are kicking on. If you turn your A/C on, the high speed fan will kick on. Leaving that on for 5 mins while parked should be able to bring your coolant temps down <170*F

10-06-2008, 11:17 AM
my coolant level is constant. Fan is working fine. Radiator is working fine too. So there's only one thing left to change, the coolant temp sensor [:)] thanks for all the replies

10-06-2008, 01:51 PM
I did the same timing belt job about 2 months ago with my buddy, on my 99.5 and mine overheated after wards also...turned out we put the thermostat on backwards lol.....took it off and put it on the right way and it runs fine

10-06-2008, 02:04 PM
You have air in your coolant system, set the heating inside the car on high and set the fan on the lowest setting, let the car run. If the car still overheats then there is a bleeder valve somewhere to get rid of the air bubble in the system.

Squeeze the top hose that runs over the intake manifold runners(the rubber part right in front of the radiator) if that is not filling up with coolant its the thermostat stuck. Just got to bleed the air out.

10-07-2008, 09:15 AM
Do you have a IR thermometer? My guess is either a clog or the thermostat is backwards.

What you can do, is check the radiator temps, & hose temps. My guess is you will have a very hot side & very cool side. Follow the cool to a hot zone, there is your clog/thermostat.

You could have also got a bum new thermostat. To test that, you place it in a bot of water on the stove. Then see at what temp it opens.

10-16-2008, 06:40 AM
Great advice in this thread. If you still can't find it after all of that, it's a long shot but check your clutch fan. I had one go in a 97.

10-28-2008, 05:07 PM
did you bleed the cooling system properly? don't forget the bleeder hose on the heater core, in the rain tray. Oh, and pentosin is the manufacturer of g12.