Overheating, water leaking out...help!

[greenmachine]

My soob is a 95 Legacy LS, and last week driving along the highway I noticed it was way overheated. I pulled over immediately and waited for it to cool down. Luckily I had my water bottle in the car with me so I popped the hood to check the level. The overflow was empty, and when I touched the radiator cap it was not hot so I opened it to find that it was also empty.

 

I dumped the water in and limped it on home (about 3 miles) without it doing too much overheating.

 

First thing I change is the radiator hoses (upper & lower) since I know they are getting old anyway. I start the car (with water in the radiator) and bring it up to temp so the thermostat kicks in (upper hose gets hot is how I tell), then rev it up...what do you know? Fluid comes gushing out from where the lower radiator hose is.

 

Here's the problem, I can only get it to leak out when I rev the engine so I can't pinpoint where the leak is (radiator bad? or water pump? hose?). Can anybody tell me what the problem most likely is?

 

Mike

[lmdew]

There is a 1/2" dia bypass hose right up by the thermostat housing. You most likely have a hole in it and when you build pressure it opens up.

[Dickensheets]

That hose sounds like the "heater hose" that runs hot water up to your heater core. Look it up in your haynes manual if you have one. Easy to replace but you may have to pull radiator and timing belt to access it.

[idosubaru]

you need to run the RPM's up while in park/neutral. just pull the throttle cable by hand under the hood and hold it while you looking for leaks. or get someone else to press the gas pedal to keep them up. be sure it doesn't overheat while you're looking.

 

no point in trying to guess, that's a terrible method of diagnosis. better to remove all the hoses and clamps and check them or replace instead of guessing which of the many possibilities it could be.

 

weep hole of water pump

water pump

water outlet o-ring of the water pum

two radaitor hoses

small coolant bypass hose by the thermostat

smaller hose coming from the water pump

heater core hoses

thermostat gasket

drain cock cracked

 

if it's leaking bad then running it then looking should show signs of wetness somewhere. if not, then intake manifold, head gasket are possibilities....

[cmiller]

Maybe a crack in the radiator down by that hose? or the heater hose like mentioned earlier?

[BigMattyD]

I agree with grossgary. You need to see the leak occuring to tell what's going on. Either get a friend to help, or turn the throttle mechanism by hand from inside the engine compartment.

 

matt

[cookie]

usually that is the easiest way to find a leak. If you don't have one put a tire valve on an old radiator cap and pump it up with a bike pump.

[greenmachine]

Well, Dickensheets gets the prize....sure enough it was the heater "bypass" hose from the water pump. It had two holes on the bottom of it, and it only leaked when it was fully pressurized.

 

Thanks for your insight guys, this message board kicks rump roast! Saved me from sleepless nights and mispent hours of diagnosis. And what's more, now that the soobie's back in action it looks like I might be able to take it out to do what it was meant to do...go windsurfing!

 

Cheers!