Source of coolant leak located, advice needed

[Oi-Punx]

I've been losing a very small amount of coolant in my 951 (about 1/2 - 3/4 cup in 6 months or so) so I decided to pull the airbox, AFM, and associated components off, pressure test, check for leaks and
tighten all hose clamps. I lost less than 1 lb in pressure in 10 minutes according to the gauge. My car runs normal, barely getting above the 1st (8 o'clock position) mark on the temp gauge. Here's what I found. Any advice would be appreciated.

1. There was some coolant residue (light crust) behind the bleeder screw down near the head gasket (adjacent to the #1 spark plug). No dampness or any signs of leaking coolant showed up here during the pressure test. I do not believe the residue came from a prior system bleed because there is no trace of it near the screw or hose clamps on said coolant line, only down near the head gasket. I am experiencing no oil/water mixing or smoke and compression is good. Anything that can be done about this besides replacing the HG, assuming that this is what the problem is?

2. I did notice some light dampness and residue on the turbo aux. water pump housing. It looks like it is coming from the housing itself and not a loose hose. Can these be rebuilt or is it better to just replace them? How much of the intake needs to be pulled to replace this? Is it a major PITA?

Thanks

[AFJuvat]

Your bleeder screw probably needs to be replaced - along withthe crush washer that goes under it.

Any water pump leak will require replacement - they are now "rebuildable" by most places.

Getting at the aux pump can be a bit of a chore - you wil lhave to remove some intake components. Pelican sells gasket sets if memory serves.

When you replace it - it is usually good practice to replace your vacuum hoses - they get brittle with age and heat.

AFJuvat

[Lawrence Coppari]

My 951 leaks a little under the bleeder screw housing. There is a sandwich plate so there are two gaskets. It uses about a cup of coolant every 3 months or so. I replaced the gaskets once; it still leaks. If you happen to remove yours and assuming it is just like mine, you might get some fine grit paper, place it on a flat surface and make sure the sandwich block is flat. As far as I'm concerned, it is a small enough leak to not worry about it. But everyone has a different leak threshold....

My auxiliary water pump also leaked. I replaced it.

[Oi-Punx]

Thanks for the responses. I now have a project for christmas break! I will most likely replace vacuum lines at the same time. They look pretty easy to get at once everything is out of the way. Is there an upgrade for the stock (nylon?) lines? Is silicone hose more durable?

I will check pelican for prices on the gaskets for the turbo aux. H20 pump and weigh that option against a new one.

[Goku]

I also have just replaced my AUX water pump. It really is a piece of cake. Got a new one here on pelican for only like 70-80ish? I'm no mechanic and I did it myself. Very simple.

[Oi-Punx]

Goku,

How much of the intake did you remove? Did you have to drain/bleed your coolant at all? Any tips on the replacement procedure?

I have checked prices and Pelican has the best price on this part at around $82.00.

Thanks.

[turbohead7]

If those repairs don't solve your coolant loss, have a cylinder leakdown test done on the engine. This will verify a leaking head gasket with bubbles in the radiator (the test requires the cylinders to be pressurized with 100psi of compressed air). You might also try one of those CO testers in the coolant expansion tank. The fluid in this tester is designed to change color when combustion gasses are present, they are reasonably priced and are very accurate.