edge04

I hope. Pretty sure my water pump finally went or going. Stock LS2 water pump on 450 HP engine running 10% under driven crank pulley. Doing some routine check over after track weekend and noticed coolant all over and under the passenger side. Some on the a/c compressor pulley and all over the bottom of the car. I never smelled it or even seen it leak or found drips on ground, trailer floor or garage floor. So my guess is its only leaking at high rpm, I red line it A LOT and burning most of it off on the hot engine parts.

That sound like a water pump going right?

So what water pump is everyone going with these days. Are any newer GM pumps better? Evans? I've run them in the past with no issues but that was on high horse power FI motors. Electric? Thanks

k24556

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That sound like a water pump going right?

So what water pump is everyone going with these days. Are any newer GM pumps better? Evans? I've run them in the past with no issues but that was on high horse power FI motors. Electric? Thanks[/QUOTE]

not necessarily. Could be a gasket. If it is leaking at the shaft, then water pump. Otherwise, maybe just trouble shoot what you have. Also the side you are describing could include leaks from heater hoses or the reservoir. You might spend $$$ just to find out the reservoir is toast.

If you have a leak that bad, then your system may not be coming up to pressure and you could be boiling the coolant. This would be bad for the engine.

If you have a coolant leak like that, you might consider staying off the track until it is fixed. spewed fluid means those of us behind you may hit it and lose tire grip. No tech inspection I know of would let you on with a coolant leak if they knew about it.

edge04

Would never go on track with a known leak!

Only thing I did was remove my A/C condenser. I disconnected the lines which are still connected to the A/C compressor and capped off (taped to be exact). Could that be causing and issue/leak?

Car never over heated, in fact ran great.

froggy47

Pressure test it.

k24556

Well the refrigerant is a gas, but there is a good bit of oil in the AC system, it is usually clear or maybe a faint yellow. Often there is green dye but in by techs. But that oil is really oily and would leave a film different than coolant, which if you are running the correct coolant,Dexcool, is sort of pink in color. if water and water wetter then there isn't much of a residue.

The first thing i do when coming off track is to do a cooldown run and check gages to see stuff cool down. Mainly I'm trying to cool brake rotors. Then as soon as I get into the paddock, I pop the hood and take a quick look for steam and oil. If there is a coolant leak it will be most noticeable then.

The coolant system must be a closed system that can pressurize. The pressure raises the boiling point significantly. That's why it is so dangerous to take the cap off when the coolant is very hot. If the radiator hose is tight as a tick under pressure, and you see no leak, then you have a tight system. You need some head space in the system, so over-filling can lead to over pressurizing and venting thru the cap. Now fluids expand whe they get hot, so if you have insufficient head space, then it may be bypassed by the reservoir cap.

Your original question was do you need to replace the water pump. I would say spend your money on other stuff, the WP on an LS is a pretty reliable beast and the same WP is installed in LS's with more factory HP than you have. The only case to replace is if it leaks at the front shaft seal which cannot be replaced by a mere mortal. AND this location is hidden by the "bell" so your only evidence of this is often engine overheating, since a leak here keeps the system from pressurizing and the coolant boils at atmospheric pressure (like 212 dgF at sea level for water). You want to be able to go to 240 dgF and maybe beyond and have the system not boil. You need pressure to do that.

Solve your leak first is my recommendation, and replace what you need to.

edge04

I do as well and never once saw steam or smelled coolant. I've had water pumps on LS go bad which is why I assumed that's the case here.

I'll pressure test it tonight. Hope I can find the leak without any dye.

edge04

ok pressurized the system and 99.9% sure it was a lose heater hose. Going to leave pressurized overnight to confirm. Should it loose zero pressure overnight or ok to lose a little? Thanks!

froggy47

I would think a small pressure drop is ok,several pounds probably not ok.



Anyone else?

edge04

only lost 3 pounds overnight

question: do the ls water pump have weep holes like the older ones?

froggy47

And some of that might be due to a cooler ambient temp and engine temp in the morning?

What press did you start with and end with? say 20 psi to 17psi or what?

edge04

never ran the car. did the pressure test at full cold. my guess is that the pump itself can't be 100% fully sealed and I did rig up a plug for the overflow tube so it may have leaked from there. There were no new drips in the morning.

18-15

froggy47

Well that seems pretty good, I have never pressure tested a "known good" cooling system to see if there is a drop or not.

Keep us posted if you do more.



I suppose even atmospheric pressure changes or elevation (mountain) changes would have some effect on this kind of test. Even a slight leak thru a gauge or at gauge connection.