Too much pressure in coolant system, even before heating up.?

Check that water pump again and make sure you did not get a reverse rotation pump. That would certainly screw up the works.

You have to have a thermostat in this car!!! Improper engine heating and sensor readings result if you don't. If you have the wrong water pump in here, you will cause engine damage!! The usual cause of cooling system pressure surges is a bad head gasket. THe cylinder head may have warped a little between the time the first pump broke, and the new one installed. This is not a difficult job on this engine, being a 5 cylinder. It is a MARVELOUS car to work on. You will need some special tools (see Blaufergnugen web-site). You may have to have your cyl head heated and restretched and resurfaced, though. Use only genuine Audi coolant. The Blaufergnugen web-site should list the proper water pump for this car. Once you get ovet this little hurdle, you will have a fantastic car. Have someone with a little savvy clean out your fuel metering box and throttle housing. Also, inspect the PCV hose for excessive wear, it has a tendency to collapse from age. Use only ELF or Mobil One in this car!!! Also, use Bosch Platinum or Nippondenso Iridium plugs for best power and mileage. After servicing, this car should last another 100,000 miles before another pump and timing belt are required. Good Luck!!!!

sometimes people remove thermostats in an attemt to keep the engine coler and make more power, its really dumb, but it sounds hypothetically effective, find out where it goes and put one in the way its suposed to be. Peopel that modify turnos tend to be the kinds of people that do things like this.

Water will create higher pressures, so it could attribute to the pressure issue. Running colant is a good idea, but i understand the money issue, and water wont kill it unless you run it for years this way, then it will begine to oxidise metals it comesinto contact with.

A head gasket sounds like the cause of the problem, and modiying the turbo settup could have very well blown it.

Do a compression test on it, im sure you will find a lack of compression in one or more cylinders.

1 double check water pump

2 t needs a thermostat to run right....asked 1/2 jokingly...How long has the check engine lite been on??no thermostat fools the engine into thinking its at wrong temp..causing wrong fuel mix and wrong timing.

3water has a lower boiling point than coolant...IT will boil over much easier] it must have 50/50 coolant/water mix to run right

4 run a compression test and leak down test and check for water in oil and oil in water

5 guy modified turbo... OH NO

blown head gasket, the compression from the cylinder is blowing right into the cooling system causing the pressure to raise on start up. note coolant doesn't have to be in the oil to be a blown head gasket.

The best way to diagnose a cooling system problem is to follow a procedure that permits you to test the various components and potential cooling problem areas is to use a procedure such as the one shown below. Be sure and follow it step by step and don't attempt to skip ANY of the steps. This video is the most thorough and detailed cooling system analysis I've seen yet.

Well, you make it sound like all this started when you replaced the water pump. It looks to me like you've got the wrong pump on there.

need to get the right gear for the pump to start with . head gasket or cracked head

You already found the problem.

No thermostat.

try to actually put coolant in it!