[Birdstrike]

It seems that I RPMs in excess of 5000, i blow the bottom portion of the water pump gasket right out! Obviously too much pressure. It's a fairly new motor (6 mos). I am on my second time fixing water pump! Last time replaced pump and radiator cap. It's also a new 3 row aluminum radiator. Cooling is not ever an issue. It's high RPMs making high pressure resulting in blown gasket!!! What the heck? Maybe a bad cap not relieving pressure? Bought a new one tonight. Also picked up new gasket and am going to replace. Pump should still be good, didn't run it dry. Just can't figure out why so much pressure and why is it not being released except out the bottom of the water pump. That's got to be a lot of psi!!!

Motor = Built 306 w/ Trick Flow heads and upper.
Most everything has been replaced new in the last 6 months.

Anyone seen this before? Driving me crazy and tired of taking front of motor apart!!!

Thanks,
Chad

[Grease Munky89]

May be a stupid question, but is the thermostat in the right way?

[acetum]

Yeah, I'm gonna have to kinda agree with Grease Munky89.. If it’s not that, which I don’t think it is. That should only cause the motor to overheat, because if you put it in backwards the coolant would never get to the radiator.

I don't think it’s the cap...

If your radiator got too hot or over pressurized it should vent into the overflow. I would check that to make sure its not clogged or a bent line into the overflow.

[spdjnky_42]

Sounds like the water pump or the timing chain cover is warped or not being tightened in correct order and to spec. Sounds like the gasket sealer is holding till forced out. Are you using the right sealer on the gasket?

[Birdstrike]

Replaced with new pump today. It blew the gasket out between the backplate of the water pump and the pump body itself, not between timing cover and pump. So I replaced with new pump.
Cooling is definately not an issue, so thermostat isn't issue. There is a flow restrictor in the line to the heater core, would that create too much pressure?
I also put a new radiator cap on just in case last was a bad cap.

Oh...when I replaced today I also put black RTV around all gasket of pump. Hopefully that will help.

Thanks

[ROCUN]

Mine did this once and I put 2 gasket there and havent happened again.

[spdjnky_42]

The restrictor has to be in there, you have another problem. Replace the bolts. Is your water pump turning the right direction?

[Birdstrike]

on 91 gt, which way should the pump rotate? I am using a different belt and different belt routing due to elimination of parts.

[Birdstrike]

I think it's running counter clockwise right now...is that right? (standing in front of car looking at the motor)