I think I have some serious problems.
 

Well I replaced the radiator today, put new coolent, etc.

Same problem, car overheating. The radiator stays cold while the engine is too hot to touch in the matter of minutes.
Me and my dad tested the thermostate in boiling water and it works. What we think the problem is that I am losing pressure somewhere therefore i can't drive with a thermostate, so we took it out.

But I don't want to drive w/o a thermostate and want this problem fixed. I don't know what it can be and it's pissing me off. I don't feel like putting the car in the shop and paying someone over $400 to fix it, if i'l lucky. I know how these guys work.

Could it be the water pump? eventhough I replaced it about 2 months ago when I got the car? Its making nosies, but I don't know if that normal or not.

Thanks.

RE: I think I have some serious problems.
 

You really have to forget about this idea of "too hot to touch" once the engine warms up it will be too hot to touch anywhere on the block. Even if you operate a cooler thermostat which is about 80ºC it is till sufficient to give you serious burns. The radiator will take a bit longer to warm up since the block has to warm up first before the thermostat opens.

What kind of noise is the pump making, belt squeal or something else? If the belt is too loose it might not be circulating coolant (2.3 uses toothed timing belt and not easy to slip). If the impeller fell off, which is very unlikely then you won't have any circulation. Another possibility is trapped air although I don't recall of any special bleeding procedures for the Audi 5 or 4 cylinder engines. Some thermostats are of poor design and don't have a small bleeder hole and close too tight trapping air. Remove the thermostat and see if the radiator warms up.

RE: I think I have some serious problems.
 

Yeah we took out the thermostate, but it's leaking water through the opening so we'll get some silicon to seal it up, or another o-ring. BUT I want the car to work with a thermostate.
The water pump is making weird pumping noises, not belt squeals. You can even hear it when you sit and idle in traffic... So could it be a water pump??

Sould i order a better 80C thermostate?

What if the car will still overheat and not circulating water right, then its the pump right?

RE: I think I have some serious problems.
 

A new water pump shouldn't be making noise. You probably should pull it off and examine it or replace it. I would also examine the mounting area to make sure that if a bearing ever failed in the past it didn't grind through the walls.

Removing the thermostat should increase circulation and is more for testing. Once you solve the circulation problem you should reinstall with a correct one. Did you replace the hoses?

RE: I think I have some serious problems.
 

Yeah I will for sure replace the thermostate once I'll find out whats causing the car to overheat. I have a strange feeling it couldbe the water pump, but I don't know. No I have not replaced the hoses, they all seem fine.

I will get to that tomorrow.. I'll take out the thermostate and seal the cover with some water proof silicone to avoid leaks. I'll flush the system a little with the Prestone Super Radiator Flush stuff that I got, and go from there...

RE: I think I have some serious problems.
 

im to lazy to read what every1 else said, did u replace the hoses when u did the water pump and radiator?

RE: I think I have some serious problems.
 

no i didnt, but I did take them apart and look at them, they all seem fine.

RE: I think I have some serious problems.
 

Radiator hoses are made of three plies, rubber, polyester cord for reinforcement followed by another layer of rubber. They might look OK on the outside but I would check the hoses to make sure that inner ply has not separated and is not blocking the water passage.

RE: I think I have some serious problems.
 

Will do. I also plan on flushing the system again top to bottom, and bottom to top. getting good water pressure throughout the whole system.

RE: I think I have some serious problems.
 

Well took out the thermostate, flushed the system, refilled it with new coolent... let it idle for a few... seems fine, the water temp thing goes a little above the 1/2 but the fan kicks in so it stays just above it almost always when i just sit there. However its like 50F outside lol so i don't know how it will be when summer hits. I got a new fan switch that would go off at 70C-75C so that sould make it a little better.

So far so good... Doesnt really seems like I need a thermostate, the car is running fine when cold, however it does heat up pretty fast even w/o a thermostate. Guess I'll just let it be for now.