coolant leak at TB side under hard acceleration.

Wheatley · Sep 16, 2009, 06:52 PM

A few weeks ago I finally got to turn the boost up on my AMS shortblock/freshly machined head. Now the car leaks coolant after a hard pull.

A little background.

AMS 2.0 shortblock
Head decked by a experienced machinest.
ARP head studs tq to 90ft lbs with moly lube
OEM-water pump, HG, ALL SEALS AND GASKETS REPLACED at the time of rebuild.
Custom full width radiator with 16lb cap 10k plus miles driven on without any problems. 100+ pulls at the drag strip without any indication of rising coolant temps. until now

The engine had 3k miles without any problems.
Never over heated
26lbs of boost on 93

Upgraded to e85 and 35lbs of boost.

It was being road tuned and driven hard most of the day without any problems until the end of the day.

Under hard pulls it will climb from 185-190 degrees up to 220 degrees. As soon as the pull is stopped it will cool back down to 185-190 and stay there during cruising speeds.

Once parked coolant will be dripping from the bottom of the timing belt cover.

The timing belt doesn't show any signs of moisture.

Things I have tried:

1. re torquing the head
2. Leakage test up to 100 psi. 0% leakage. No bubbling at the radiator with cap removed.
3. coolant system pressure test. The tester would only pump to 10psi. no leaks
4. I might have caused this problem. I connected the coolant pressure adapter to an air tank. Unfortunately I didn't notice it was at 80psi. Immediately it started spraying from the water pump. But not anywhere else. I removed pressure and the leak stopped. I turned the regulator down to 10 psi. No leak at the water pump or anywhere else. As soon as I hit 20psi the water pump started leaking coolant.

Could this all be from a failure at the water pump or is there possibly another problem at hand.

Any help would be greatly appreciated.

WHTEVO · Sep 19, 2009, 10:14 PM

Was it a new water pump? Is it leaking from the little weep hole on it?

Aaron

Wheatley · Sep 20, 2009, 10:42 AM

I did pressurize the cooling system but I wonder if I caused the leak with too much pressure. I have to order a new one anyways so Im just going to throw a pump on it and hope it doesnt blow again due to another problem. I dont have the time to wait on parts to pull the head. Its almost the end of the track season up here and I want to make passes. Ill let everyone know once the new pump arrives.