Let's back up here a little. Hoses exploding is due to pressure overbuilt. We need the whole story from the beginning in details please.

When did the overheating starts? Was anything done to it before that? What has been done after? Which hoses exploded(need location please)?
Are the coolant clean? When thermostat was replaced did you take a peek at the water pump blades?

From the time the car is cold and until the car gets to normal operating temp, was the upper radiator hose hot? If it was hot was it tight to the squeeze?

 

do the pipes get hard? if so are the cooling fans working?

 

Ok Ecartoys here it goes. I was driving back to my house one day when I heard the explosion of a tube from the engine obviously. I then quickly drove the car home as the water temp gauge was rising above regular temp. Then the red oil temp light came on just as I pulled in the driveway. I opened the hood and noticed a cut in one of the hoses (oil coolant hose). I replaced the hose next day and started to drive it. I was told that when the temp. rose it was because I needed to replenish the lost water when the pipe broke. I was driving to school whne the car started to steam. I look under the hood and what do you know the same hose broke. I managed to drive the car home safely. I replaced the hose and then took it around the block. I took it back to the house every time it started to overheat to refill the coolant. I then noticed that there was another hose that was mushrooming aroung the end. That hose was the water pump hose which later burst, I then replaced that hose. After all of this the car is still not running at the right temp. I then replaced the thermostat, seeing if it was because it wasn't opening and letting the water in. After all of the the car is still running hot. So what I did was I flushed the radiator to see if it was that but it wasn't , the radiator is fine and soo is the thermostat. Then Car will overheat and not take any little or no coolant. So I basically I have come to two conclusions: (A) Air gap or (B) Water pump malfunction. I don't know about anything done to the car before I bought it. I bout it with 108 k miles on it. Now it prob has about 112 k miles on it. after all it's a '97 A4 1.8L turbo.

 

I'm confused about a few things. You say that the oil coolant hose broke. What is that? Does it have water or oil in it? I've never heard of an engine getting so hot that it bursts a hose unless the hose was bad anyway. Is there a way he can check to verify that water is flowing?

 

T_REV_17,

More questions:

"I opened the hood and noticed a cut in one of the hoses (oil coolant hose)." - Where exactly is this hose? Left or right side of radiator? Upper or lower? Etc.

"I took it back to the house every time it started to overheat to refill the coolant. I then noticed that there was another hose that was mushrooming aroung the end. That hose was the water pump hose which later burst, I then replaced that hose. " - I am assuming that this is hose that is in the area of pump and thermostat. Mushrooming can be a couple of things - air pressure or oil contamination. You did not mention if the coolant is clean.

"After all of this the car is still not running at the right temp. I then replaced the thermostat, seeing if it was because it wasn't opening and letting the water in. After all of the the car is still running hot." - So you are not losing coolant anymore but the car is still overheating. Does the electric fan comes on at all?

 

1) The first hose that split is to the oil cooler. About a 5/8 hose that runs from the lower coolant tube (metal) to the oil cooler just above the oil filter.

2) The second hose runs from the water pump to the lower coolant tube. Just a small elbow. And, yes, the coolant is extremely clean.

3) The electric fan is not coming on at all. I don't think I know what switches it on. (Temp sensor or other?)

 

At this point I think the diagnosis is that you have some blockage somewhere that creates pressure causing the hoses to explode. You have checked the radiator and it is flowing properly. Have you check to see if the complete system is flowing the way it should. If blockage is a problem it is most likely from your water pump. Try back flush and see if you can clear it.

I have said this many times so here goes - Do not buy water pump with plastic impellers. Once they are heat fatigued they get brittle and break off in small chunks flowing through the system causing problems. Also with partial impellers it will cavitate and creates a lot of air bubbles but not flowing much coolant. We prefer the Hepu water pump with polished brass impellers. They also last a lot longer with better bearings.

The electric fan should come on at high when the temp is past 3/4 point. The switch can be located on either the lower radiator hose or on the lower left side of the radiator. Also the fan control module is on the left side frame rail. You can test it by jumping the wires to see if both the fan speeds come on.