lol im sorry but still a noob but umm ya a belt drives the water pump in these cars quattro and the v6. jesus i maybe wrong but im not that much of a noob. chance are its a faulty thermo cuz these water pumps are crazy durable with my research.

 

Keep in mind if your water pump goes it may take your timing belt with it and smash valves. Be careful, even if you have read that they are strong.

 

Our timing belts aren't driving the water pump, so that risk is low.

 

So i just replaced the thermostat. and now its worse than before. the engine never completely overheats, just about 3/4 way up the gauge. When i took out the old thermo, i noticed the old o ring was pretty much dientigrated. Now what? what should i look at next?

 

So, just fyi, I had the same problem. However, when I did my thermostat, I also did my timing belt and all the seals. Did you perhaps, take the OLD thermostat and boil it on the stove to see if it opened? I ALSO replaced my radiator while I was at it, it was clogged. If your heater works fine, and your new thermostat is working, you might want to check to see if your radiator is clogged...mine was, I have a 98 A4 Quattro with 268k miles on it.

 

Wanted to elaborate on my previous reply. I'm assuming since you replaced the thermostat, when you unhooked waterpump and radiator that you put fluid back in it when you put it back together and it's not low? Not trying to be rude, just checking. If your system is bled right, your heater should work. BEFORE you go and replace the radiator, when you're at an idle and it's at your 3/4 mark, pop the hood and make sure your clutch fan is spinning. It should click on and off, you should also be able to hear it click on and off...and make sure one or more of the blades aren't missing....

 

yes, i made sure to fill it back up. my clutch fan pretty much stays on all the time also. my heater works fine. Maybe i have an air pocket in the system? Whats the best way for me to bleed it?

 

Ok, so question, when you first start the car, is the fan running too? like when it's cold? Like I said, if your heater is working fine, your system SHOULD be bled right. Looking at your previous posts, you did bleed it correctly. If you have an air pocket, it should cause an intermittent overheating...

do you have your AC on when cruising up the highway or ideling?

It's always hard to determine without looking at it. If your thermostat works fine for sure and your heater is flowing correctly, and your water pump is working correctly and NOT leaking, at this point, I'd have to say that your radiator is clogged....they are NOT that hard to pull out, you don't have to remove the front end, then look at the cores and see...you can get them for under $100 online or from some parts stores...

Also, you are sure it is the HIGH TEMP light coming on and not the 'icon' for low coolant from the reservoir right?

It also could be your temp sening unit malfunctioning.....

It's hard to determine, when did this first start happening?

Like I said, when I redid all mine, my radiator looked like crap, obviously after 270k miles...so I just replaced it. When my thermostat was failing, my heater didn't work, and my car heated up, then went completely cold....and back and forth....

 

when i have my ac on, it seems to get hot faster. if i run with the heater on, it just prolongs the inevitable. My clutch fan kicks on as soon as i start her up, and stays on. ive had this car for a few months, since the biginning of summer, and its always had this issue. i dont have a hi temp light come on, it just runs bout 3/4 way up the gauge. i could change the coolant temp sensor just to try the easy parts, but the previous owner replaced that here a few months ago. is there a definite way to check if its my radiator? everyone i have consulted about this problem has been dumbfounded, and i work at a ford dealer where all the mechanics have no idea whats wrong

 

If it's not overheating....well, it might be the gauge too. Since you work at a dealer, have a mechanic run a pressure test on the system. It's hard to tell what it is if that's what it did when you got it?

Also, when it's that hot, have them test the temp of the engine manually with their equipment...it might be just a 'glitch' in the gauge on your dash....They should run temp wise anywhere from 175 -200 degrees F, that should be the middle of the gauge on your dash....