Ben C.

I have a 94 Caprice wagon that is overheating all the time. Already replaced the thermostat, then removed it completely leaving just the seal in the housing.

Water is not circulating through the system, but when I filled the radiator side of the system through the thermostat housing, bubbles came out from the engine block side. That led me to believe that I do not have a clog, so the water pump is the most likely culprit.

But when I fill the overflow reservoir with water and rev the engine, it pulls the water from the tank as long as rpms are high. When I let off the gas, water comes rushing back into the tank and it overflows with foamy dirty water. This acts like the pump is OK, but that there is a clog keeping it from pushing the water all the way through the system.

I'm not sure if my next step should be to replace the water pump or look for a clog. Also not sure if I can replace the water pump without having to replace the water pump drive shaft and seals, since that requires removing the entire timing belt. If I can replace the pump without messing with the drive shaft it would be a lot easier.

Thanks for any help.

Rednucleus

Have the system flushed before throwing parts at it. Original radiator? Last time antifreeze changed?

Ben C.

Don't know what's original or what's been done recently, I bought it a couple of months ago off Craigslist from a Big Rig mechanic.

I think My question is mostly moot now, though, since it has developed a leak from the water pump now. Water just drips out from the bottom of the water pump housing when I fill the reservoir.

I'm hoping that it's just a couple of bad fins that's been keeping it from working, and putting anew pump on it works.

I've run about 20 gallons through it in the last week or so, but it doesn't go all the way through the engine because the radiator stays cool the whole time.

The Radiator hoses get warm, but not as hot as they should be. Both hoses feel like they are empty and warm when the engine isn't running, and when it's hot and running, they feel like they're full of hot air or steam, not fluid.

The fluid just boils off back into the reservoir's overflow tube and shoots steam out the bottom of the engine compartment. So I guess you can't really say I've run any fluid "through" the engine, I've just done the best I could to flush it and it hasn't worked.

I'm hoping I won't have to do anything with the timing chain, though. I want to get this thing running with as little intervention as possible.

WyrTwister

With no tstat , that hose , going to the radiator will mot normally get as hot as usual .

Replace the water pump . ASAP .

Flush the cooling system or take it to a radiator shop and have them do it ( including the heater core ) . If it still gives problem , turn it over to them to fix . And have them install the tstat too , or you do it . Running it too cool will cause the computer to run the fuel mixture too rich .

God bless
Wyr

( Does it have an electric fan & is it working correctly ? )

SBchevyfan

Also make sure you are not mixing DEX-COOL antifreeze, with regular antifreeze as they are not compatible. When they mix they can form a plug that can clog your water jacket.

WyrTwister

I have heard negative things about DEXCOOL . :-(

God bless
Wyr