Jeremy Beck

I have a 2002 Audi A4 I’ve recently put a new water pump , coolant resiviour, thermostat , and all new temperature sensors there’s no leaks and the coolant flange in the back is new but yet randomly it’ll start over heating the go back down to normal temperature I have no idea what could be the problem

lyleswk

Fans work?

Jeremy Beck

Yep fans work

lyleswk

There is another thread that goes through the symptoms of a blown head...unless someone else has a better thought.

ShakesterB6

Are you using G12+ or equivalent coolant? There was a time when my B6 was driven by brother who ended up putting green coolant in and it would overheat in traffic. I drained and flushed it and replaced it with the proper coolant (pink) and have never had an overheating issue since.

JJm64123

if i am replacing the timing belt/water pump because of possible over heating should I also have the head gasket done? I'd hate to have it all taken apart to just have to do the head gasket shortly after.

Yoop

I wouldn't just change the head gasket without doing some tests. You could first look at the spark plugs and see if any look different, if there's a coolant leak into a cylinder the plug would look cleaner or different from the rest, Also do a compression check and look for low cylinders and you could have a shop test for hydrocarbons in your coolant.

JJm64123

yea I think I will try that before ripping more of this motor apart. I have been also searching about my fans not working. I've read that you can directly wire the fan to the battery. would you know which wires I connect to on the fan harness to make them run? do I use the wires going into the fan control module?

Btt118

What Yoop said above. Inspect plugs and get compression test. If you are not seeing any coolant dripping out anywhere it could be a leak passed the gasket or a crack in the head itself. I just dealt with this issue in a 2004 a4 w/ 220k mi. Got another head online for $500. You could also get a head at the junk yard. Either way make sure you have it carefully inspected at a machine shop before you go through all the trouble of putting it on.

If it does end up being the head then yes you would do a new timing belt/water pump at the same time since you’ll have all that off.

Could be other stuff too.

Does the cabin heat work consistently?

lyleswk

To answer your fan question, the only way I could figure out how to do that was to cut the wires between the FCM and fans; the wires do not unplug from the FCM or fan. Then just get some leads and jump to the battery.