Head Gasket Test
 

What is the best way to determine if the head gasket needs to be replaced?

83-944 N/A

if you are blowing out white smoke :)

I have also seen a leaking gasket put products of combustion into the cooling system or put oil into cooling system. If POC go into water, your water system will overpressurize and will vent. Venting will cause more brake dust to cling to the driver's front wheel than the passenger front wheel. It will also cause a loss of water.

Lawrence, how do you know so much? it baffles my mind - seriously.

Don't know so much. But I have a friend who does DE's with me and has a 944turbo. He would lose water and his left front tire would always get dirtier than the right front. His car braked in a straight line so it did not appear to be a brake problem. His water level would go down. The problem was his head gasket leaking causing venting from the reservoir. The little vent tube directs the coolant near the wheel under the car. The moisture made the brake dust have a greater tendency to cling to the wheel.

Another friend of mine had his 944 head gasket let go big time. It looked like a steam engine. Quite a show.

On the lack of boost stuff, it is my own personal experience.

Compression, vacum, and leak down tests.

Sypmtoms are:
White smoke from exhaust
Oil in watter
Blown radiator cap.
Cracked expansion tank

I've never put Watter in my car, where does it go? The fuse box?

There are also some testers that use a fluid sensitive to Hydrocarbons, it changes from blue to yellow. You place it over the coolant tank and pull some of the steam into the device and if the head gasket is blown even slightly it will start to change color.
A automotive gas analyzer will do the same thing.