Weird cooling system troubles

Pull the water pump off, if its good you cost yourself a little RTV, if its bad you found the problem.

Pulled the water pump out, and not only does it look brand new like I was told it was, it looks perfect. Pulled the radiator as well, and sprayed my garden hose in the top hose fitting while watching it flow from the bottom ,and that even looks fine. Took the hoses off the heater core, and flowed the garden hose through them, and the water gushed out of the water pump housing. I am at a loss here guys. Any ideas? No water in the oil, and no oil in the water. Overheated in a two mile drive with a shut down for a couple of minutes in the middle.

Fan wired in backwards?

Compare the pump to pictures of other ones on parts sites. Maybe it has a wrong rotaton impeller? Say, you don't have the belt routing spinning it the wrong way do you?

Belt driven fan, and I don't think there is a way to make it turn different.

Also inspect the rad carefully, the fins can corrode/rattle loose from the tubes.

If both heater hose are hot at the firewall, the trouble is in the air doors and or the temperature control. Some are vacuum controlled, others are electric and could even have a cable operation.

Mazdax605 wrote: Belt driven fan, and I don't think there is a way to make it turn different.

Ok. Just assumed most people ditch those damned things after the clutches fail in them. So, how is yours doing?

Honestly, I'd say you may have ancracked head or coolant jacket in the block that only shows its head when it gets warm and allows the coolant system to get pressurized by combustion chamber pressures.

Oil and water don't have to be mixing to have a bad head gasket. Also it is easy (on some engines at least) to get the head gasket in upside down, especially if you're in there the first time, etc.

9 times out of 10 when you've got coolant pushing into the overflow, you've got a bad HG. The first time might be a bad radiator fan or radiator or radiator cap, but after the third or fourth time without fixing it? The head gasket is toast. Pull it and know for sure.

Not what I wanted to hear. I know the head gasket was changed when the engine went in but that doesn't mean it was done correctly. Anyone want to take this thing off of my hands?

So revisiting this. I have a few questions though. If the head gasket were bad somehow (suggested above) that it is allowing combustion gasses or compression into the cooling system somehow, wouldn't I get white smoke out of it on start up or bend a rod(coolant pooling in the affected cylinder)? I ask that because if it were blowing into the cooling system shouldn't the pressurized system push back when the engine is shut off? I know the only way I will know for sure is to pull the head, but I don't want to do it, and find nothing. For the record the oil looks perfect, and there is no oil in the coolant. I am dumbfounded by this problem. Water pump is brand new looking, and in great shape.

belt driven fan you say? Those have a clutch in it.

With the car off and cool, see if you can spin the fan. If it spins freely, it has a clutch. Run the car a bit, and shut it off while looking at the fan. The fan should stop when the car stops, otherwise the fan clutch is toast.

If the fan doesn't turn freely while cold, then it's hard mounted and might be a flexi fan type, where the blades flex with rpm. Those can be put on backwards pretty easily.

Silly and easy things to check and eliminate.

You could always send off a coolant sample to check for combustion gas contamination, that would tell you for sure that the problem is a cracked block / cracked head / bad head gasket seal.

Get it hot and see if you can stop the fan with a rolled up Car and Driver magazine. If so, you have a problem. If not, you have confetti.

But even if the clutch fan was bad don't you think the car would stay cool when in motion?

Everything is inter related. It takes two seconds to check, make sure it's not a problem. Heck of lot easier than pulling the head...yes?

Yeah, but the radiator, water pump, and fan are all off of the car at this point. I will check it when I get it back together. The car did come with a spare clutch fan that is orange instead of the white one that I pulled off.

Ok, fan is off.

See how it spins now, see if it stops spinning if you put some heat to it from a blow dryer or something. When warm it shouldn't spin freely.

Didn't see any mention of a backwards thermostat.

Well I put the new one in that same way as the old one, so I doubt it is in backwards.

Mazdax605 wrote: Well I put the new one in that same way as the old one, so both were installed incorrectly.

ftfy (possibly).