Car Problem

When I had that problem on a 1991 Cavalier the water pump failed so the coolant boiled (I could hear it) and came out of the overflow tube

yea the coolant bottle has in the vw/audis has a overflow hole so if it gets to hot it will push it out there. I would have to say if your coolant is overheating it may be the water pump not working correct. if you have not had the water pump done before that would mean you have likely not done the timing belt. I would recommend a timing belt change at this point and have it done with the kit as it will come wit ha new water pump and thermostat. The belt needs to be done once every 90,000km and all the parts are normally done at the same time. I would have a rad flush done at this time as well and make sure the heater core is flushed properly when this is done. If they do the coolant wrong your heater core will no longer pump heat. Its simple to bleed the heater core just turn full heat on in the car when its being drained and same thing when topping up the fluid just make sure the garage you take it to is either vw or audi or a specialist of these two brands only. for the v6 engine this job is roughly 1400$ canadain at a specialist you can likely shave 400$ off i know some that can do it for 800$ before tax but usually they make me wonder how good they are as those shops are usually in a barn or a dirty shop some place :P any ways a few other places the v6 leaks is the coolant pipe directly under the intake manifold. Its about 300$ to fix at a garage or 65$ for new gaskets and seals. one way to tell if this is the issue is antifreze puddles under the intake manifold and antifreeze steaming off the back of the engine bay as the pipes go into the back of the heads there. This job i finished in 4 hrs myself and requires removing the intake manifold and the egr valves so if you can do the job your self make sure you get those gaskets. the only other parts needed is the 3 O-rings for the pipe. lube the rings up good cause those new rings are a bugger to get back in. A few other reasons for audis to over heat is cloged lines due to not using the proper antifreeze, Like green antifreeze for example if its mixed with the proper coolant it tends to gel up and block the heating system, and the only other thing would be the clutch fan which tends to fail in its old age and the electric fan which has a tendency to burn out due to corrosion after like 6/7 years. I would replace the electric one with a new one. and if it comes with the wrong wiring harness just take the harness off the old one and put it in its place. any ways hopes this helps.