View Full Version : Help! Car overheating after timing belt job.

03-10-2008, 09:01 AM
I tackeled the timing belt job on saturday and surprisingly it was much easier than i thought it would be. Took me and a friend 6 hours to complete. After everything was back together i filled the car back up with coolant and took it for a drive to make sure everything was ok. After about ten minuets the car started overheating. I figured there was probably still air in the cooling system that was causing it to overheat so i spent all day sunday trying to get it out and still no luck. It still seems like theres air in there and still overheating. I also replaced the waterpump and thermostat while it was all apart. I was also thinking that it could be the thermostat but it seems to be working properly and i have heat. Does anyone have any advice on how to get the air out or why i would be overheating. Any help would be greatly appreciated. Cars a 98.5 1.8T quattro manual.

03-10-2008, 09:16 AM
when you filled it back up with coolant, did you have the coolant jug up on an angle, heat on, and keeping the rpms between 2-3k? thats what i do everytime i drain the coolant and fill it back up...or maybe a faulty thermostat?

03-10-2008, 09:24 AM
No i did not do that and it seems like no matter what i do i cant get the air out. Im thinking now it just might be best to drain it all out and try refilling it again. I read that theres a bleeder hole in one of the tubes by the battery for the heat the helps blead the system. I think im going to try to open that up and refill it the way you just said. I realy dont want to have to empty it all out and refill it but im starting to think i dont have a choice cuz i cant seem to get the air out and it still overheats.

03-10-2008, 10:08 AM
Try draining the coolant and refilling. Use Prestone G-5 if you can find it, or even regular coolant, so you don't have to keep spending $$$ on G12 until you think you have axed the problem. Once you have solved the problem, drain again and refill with G12.

03-10-2008, 10:11 AM
when you refill, do it slowly a little bit at a time.

Make sure you massage that big coolant line infront of the IM while your doing it.

03-10-2008, 11:11 AM
If cam timing is advanced, it CAN cause hot running...

03-10-2008, 11:58 AM
just leave the cap off top off. and let all the air bubbles come out at idle. i usually idle for about 15 min or so, it's going to boil over a little bit with air rushin out, just keep it topped off. then drive it around to make sure your temps are within spec. audi/vw motors hate gettin' flushes.

03-10-2008, 12:08 PM
did you bleed the coolant with that little allen screw on the top coolant line? if its like my b6 i filled the overflow tank but it wouldnt take much.. i bleed it via that top screw and it took more two liters.

03-10-2008, 12:56 PM
What little allen screw? The only place that i heard of to bleed it is a hole in one of the lines next to the battery for the heat. What i was doing yesterday was letting it idel with the cap off and then giving it some gas so the thermostat would open and start circulating the fluid. It would then bubble out over the top like air boubles were coming out. Once it calmed down i would put the cap back on and let it run till it would start to overheat. Then id shut it off to cool, then remove the cap and it would need more fluid again, i would top it off with fluid and repeat the process, but i did that at least 6 times and still overheating and it still bubbles like theres air in it, seems like im just going in circles.

03-10-2008, 01:18 PM
well you say you have heard of the line by the battery, but did you use it to bleed the system? thats what i do and it works everytime.

03-10-2008, 01:20 PM
I did not use it to fill the system up because i did not know of it. I tried to bleed it afterwards and I wasnt havent any luck. What process do u use to bleed it using that hole?

03-10-2008, 01:34 PM
Burp it! I don't know where the burb plug is, but I have heard the legand of it on the 1.8T. I would just drain it and redo it myself. Never had any issue aslong as I fill it up slow. I do like biweekly TB jobs. Seriously, draining and refilling should take like 15 minutes man.

03-10-2008, 01:37 PM
Yeah thats what i plan to do tonight because nothing else is working. Think i might just put the old thermostat back in too, the new one seems to be working, but im not totaly sure and i didnt have overheating probs till i replaced it and the fluid.

03-10-2008, 01:39 PM
just leave the cap off top off. and let all the air bubbles come out at idle. i usually idle for about 15 min or so, it's going to boil over a little bit with air rushin out, just keep it topped off. then drive it around to make sure your temps are within spec. audi/vw motors hate gettin' flushes.

ya, thats what i do.. it works like a charm..

03-10-2008, 01:46 PM
When is the auxillary electric cooling fan supposed to come on? I havent seen it come on yet while it was over heating.

03-10-2008, 01:55 PM
it comes on with the AC compressor.

You're overheating because you have an air pocket near the thermostat. Most of the engine cooling is done with the clutch fan. I would double check you have the connector hooked up on the rad support for the electric fan though. You need to massage the soft coolant pipes with you hands. Yeah it looks gay....deal with it. lol

03-10-2008, 02:12 PM
Thanks for all the info guys. I'm going to work at it more tonight and ill let you know the outcome. Hopefuly this gets resolved soon. I want to drive the damn thing now that im not so scared of the timing belt braking, lol

03-10-2008, 08:40 PM
Problem fixed. I drained out all the coolant and used the bleeder hole this time to fill it. Got all the air out the first time and not overheating anymore. Thanks for the advice!