Friday, I was driving my car home from work, and while at a red light saw smoke coming up around the hood. Stoped and cheked it out. It was spraying water from below the water pump! Wtf? Just replace the pump today, and the upper and lower hoses about two weeks ago. So what can cause water to spray, not leak from the front of the engine?can't seem to find it, any sugestions would help.91 z28 305 tpi, bone stock

 

It was spraying water from below the water pump? Are you positive it wasn't shooting from the radiator into the pump/fan blades?

Could be something simple like a clamp that backed off and the hose end is leaking, the pumps impeller seal, or the pump/block gaskets. That's everything coolant related in that area that I can think of.

 

Check the plate on the back of the pump. I've seen them come new and be loose. Other than that, it shouldn't be too difficult to find the leak. Just clean everything up and follow the water.

 

That's what I thought it was. I put a new pump on it in feb, and just swaped it under warrenty yesterday in hopes that it was the issue. Not the problum. The radiator is also only 6 months old. And if it had a hole it would leak cold wouldent it? It only seams to start spraying when it breaks 180degres. Dosent leak cold. I'm doing the thermistat Thursday, will see if it helps any. also when I changed the pump, I checked for cracks in the block, didn't see any. If its a small crack It wouldent spray like a water hose. If it was a big crack id be able to see it. So any other sugestions would help

 

can you "rent" a pressure tester from your local parts store?

 

Have you tried to find the leak while the car is parked and the engine is running?

Clean everything up, have the car in neutral or park, pop the hood, manually hold the throttle open to about 2000-2500 rpms and wait for the motor to heat up to 180 (where you said the problem occurs at), then Watch...

Its gotta be coming from somewhere....

 

If it's only happening above 180*, are you sure it's not your thermostat housing or upper radiator?

I have a Summit aluminum radiator that sprung a leak only when running- it was on the cap above the AT cooling line connectors. That was a royal PITA to hunt down- found out the cap had a dry rot crack that ONLY showed under either pressure, or if you squeezed it. Rubber parts, especially, won't leak until there's enough pressure to overcome the elasticity of the rubber. Mine was a $1.50 fix.

Did you replace the upper and lower hoses? Also, do you have a heater hose going to the pump? That would be another possible point of spraying under pressure.

 

Just called the paerts store, they do have a pressure tester, but its $150 (ouch) refundable. Won't be able to do that till pay day. I have tried to spot it while its spraying but no luck. Can't see it top side, can't get under it enough to see when its spraying. A hot coolant shower isn't my idea of fun... any cheater way to perssure test it? Btw, its a 5speed, does the even have coolerlines?

 

Maybe somebody else will chime in with a better idea, but I've always disco'd the hose from the radiator to the puke tank and plugged shop air into the puke tank end so the pressure was going to the radiator starting at 7psi, then 14, etc.

Works if you have a known good PSI gauge on your compressor.

 

I pulled a JY intake manifold once that had an air fitting tee'd into one of the coolant ports with a rubber cap tightened over it.

You could also fit a schrader valve into one of the lines and use a bicycle pump.

Replacing your t-stat won't get you any closer to finding the leak.

 

Thanks for your help everyone found the leak, lower hose had a pinhole. Duh...

 

Glad to hear! Kick ****!