alright, well i replaced the water pump and it started running hot.. so i replaced the thermostat and it didn't help at all...

 

i can let the hatch sit there and idle all day long and it never gets hot, but soon as ya start drivin it, up the gauge goes..

 

i'm a bit stumped on this one... its got a aluminum radiator outa a legacy in it, so radiator cooling is great.. fans on or off, doesn't make a difference, niether does the heater on or off..

 

think i got a bad pump from the parts store?? any suggestions??

i ran some radiator flush thorough it today also.. just to clean it out..

Did you burp the air out of the system?

 

Many times the thermostat is wrong out of the box. I replaced a head gasket once and had already put a new thermo in before hand. Started up with new head gasket and thermo and it overheated. Got another thermo and it ran correctly.

 

Is it the correct mixture of coolant to water?

 

Did you replace the pressure cap? If the cap is bad the pressure won't be enough and the h20 pump won't pump enough coolant through.

ohh yeah forgot to mention.. the old radiator cap was pretty worn, and when i did the system fluch i watched it over flow from the cap.. so i replaced the cap, and it acctually ran hotter with a new cap.. go figure..

 

 

one thing i did notice tonight, was that after a 20 min drive into town and it runnin hot.. i got out and the radiator was cold, but both hoses to and from it were hot.. so i popped the cap, didn't get any spray and radiator was full..

 

all this started after the new water pump was put on.. the old one with bad bearings, grindin, and wobblin kept the car nice and cool..

Was the h20 pump oem or something from AZ?

 

And how about the cap, oem or other?

 

Did you burp it?

both pump and cap from fisher (federated parts)

 

whats the procedure for burpin an ea81?

 

already let it run till the thermostat opens, with heat on, and refilled...

Sometimes the impeller comes right off the pump. So both hoses are hot, but no flow is actually taking place.

I don't know the exact way it is supposed to be done on this model. Maybe somebody else will chime in.

 

I know a universal way is to take the pressure cap off, or leave it in the first lock position , and run the car for a few minutes and the air should work it's way out. Some cars have a bleed valve, and some are easier to burp than others. Sorry I couldn't help more.

Just an opinion, but...

1) Does'nt sound like a rad, pump or stat problem cause it would overheat when idling. My fan comes on only when the engine idles.

2) the fact that the engine has to work to overheat makes one think of cylinder heated gases getting into the coolant when the cylinder pressure is high enough. Crack or head gasket ?

Just a possibility. Is there an overflow tank on this car? Bubbles in the coolant?

The cold rad with hot hoses is a mystery to me though.

Take the thermostat out and open the cap to verify the pump is operating by observing flow.

Turn the heater on and see if you get any heat.

Try flushing it again by using a flush/fill kit with a T connection in the heater hose.

To bleed it you may need to loosen a heater hose, the cap on the T of the flush/fill connection, or the thermostat housing. Also park it with the nose uphill somewhat when bleeding.

Make sure the pressure rating on the cap is correct.

well i think i solved it.. put my old (known good) water pump on, no difference.. so i pulled the thermostat completely out..

 

at idle i gotta have the fan on to keep it cool, but when drivin the temp gauge never moves off the first bar on the temp gauge..

 

so i guess that new thermostat i got is bad.. gonna take it back tomorrow and get a refund.. figure i might just drive it without one... its 40 degrees outside now, and it was still puttin out enough heat to heat the car nicely..

 

on another note, after drainin the radiator, pullin the pump, and takin teh thermostat out, it only took 3/4 of a gallon of water to fill it.. seemed odd to me.. but it is a 1core legacy aluminum radiator, so not sure what its supposed to hold..

Could be due to plugging in the cooling channels. Removing the thermostat removes some flow restriction and might be enough to get a good circulation.

I had the same problem with a water pump from Autozone. Would be ohkay at idle, but once off idle, it would heat up pretty bad. I took off the water pump, and the stamped metal impellar was loose on the shaft, I could hold the pulley, and still turn the impellar, I turned it a couple time, and it pulled right off the shaft. I took it into AZ and threw it at the manager (as is my custom when parts are bad from there). I got a pump from carquest that didn't have the flimsy stamped metal impellar, but the nice cast one like the OEM part does, but cheaper.

heh, yeah i had it pointin in the right direction..

 

as for the pump, when i took the new one back off, i check the impellar to see if it was loose... was nice and tight, and also had 5 vanes, and it was cast like the oem..

 

i did think about somethin pluggin the cooling system somewhere, but the only thing i could think of would be coolant hose rotting from the inside out, and pluggin up.. otherwise the engine, radiator, etc is alsmot spotless on the inside..

Maybe at this point it would be worth it to replace some hoses.

Will be the first one to congrat you if a new stat cures the problem Moose. But buy a OEM one. I made a comparative test on an aftermarket one and an OEM one once and the AM does'nt come close: opens later, does'nt stay open as long, does'nt have a comparable flow, etc.

 

Just one thing bugging me though. If the stat is responsible, how come you get no overheating even with a long idle?