coolant not circulating throughout engine!!

[swaggawagon]

my 99 a4 quattro avant overheats with full coolant, just replaced the coolant flange due to a leak, and did the whole thermostat in a pot of boiling water test and it seems to be working. i also dont think its a water pump, but im still not sure. any body have any ideas???? im stuck!!!

[stormscr3]

I would replace thermostat ASAP - They're less than $10 and could be the culprit - even if it passed the boiling water test. (Just my two cents) If that is ruled out I would look to Water Pump.

[SGS]

Water pump. If I remember right you can take the hose off that goes to it and stick a screw driver in there and feel for impeller pieces if it has shelled out...

[swaggawagon]

i did replace the thermostat, i even tried running it without one at one point. and as for the water pump, what do you mean shelled out, like theres not pieces to the impeller?

[redline380]

definitely check the impeller to see if it is still rigidly connected to the shaft. you are exhibiting classics symptoms of an impeller that has become unmated to the shaft

[audi-medic]

Bleed the system

[swaggawagon]

i just checked it the impeller isn't spinning freely and it seems to be ok.

[redline380]

i just checked it the impeller isn't spinning freely and it seems to be ok.

check harder

[walky_talky20]

Just for sake of discussion, on all 1.8T's (internal or external water pump), the water pump impeller is easily checked when the t-stat is removed.

[swaggawagon]

could it be blockage somewhere in the system?

[redline380]

could it be blockage somewhere in the system?

I highly doubt it. has the coolant temp sensor ever been changed?

[swaggawagon]

not that i know of no

[redline380]

see what color it is. if it is blue, youll want to try a green one

[Koldham]

if it didnt overheat before the coolant flange swap, and now it does...

[swaggawagon]

if it didnt overheat before the coolant flange swap, and now it does...

it started before the flange swap but i figured to go ahead and replace the flange because it had a crack in it maybe it might be fixed.

and as for the temp sensor, is it really possible for it to be faulty even if the coolant is not circulating?

[redline380]

it started before the flange swap but i figured to go ahead and replace the flange because it had a crack in it maybe it might be fixed.

and as for the temp sensor, is it really possible for it to be faulty even if the coolant is not circulating?

how do you know the coolant isn't circulating?

[swaggawagon]

how do you know the coolant isn't circulating?

when the engine overheats the coolant is still cold, and i also pulled the small hose connecting to the overfill tank and revved to 2000 rpms and there was no steady flow of coolant, so i guess it is water pump failure :[

[SGS]

The plastic impellers like to crack. I had mine crack into 4 different pieces and I remember when I took it off that I could have easily checked it before I took everything off to see if I could spin it or if it was seized. The impellers are a known issue and are likley the first to go with the pumps

[woolveren]

Check WP pulley, it might be slipping...if not, probably broken impellers.

[ECS Tuning-Audi]

If you have no coolant flow its pretty obvious the water pump is shot. We have replacements available below!

Assuming you have an AEB you'll need the pump pictured.

Click HERE to order or for more information


Jason