Overheating (symtoms of a bad thermosta

Edman1000

Registered User
I have a '90 XR7 and it is heating up way too hot and then all of the sudden the temp drops and the heat starts to blow. It did this about five times. So i figured it was the thermostat. I replaced it with a 180. same thing. I start it up all the coolant goes into the puke tank and it acts likes the thermostat isn't opening. I was told by a couple of people that the water pump took a crap but I don't see how. has anyone ever heard about a water pump where the impeller comes loose from the shaft? What else should I check?? MAybe I'm not filling the radiator right, but I really don't think so. It could be an air bubble, right? I hope it's not *ulp* head gaskets. I just bought the car last week. If any one has had this problem please reply and let me know what to check.
 
Is the fan coming on when its supposed to? Its a 2-speed sucker that is controlled by the ICRM. Switches to low speed at 212'(i think) and high speed at 230`. Check grounds at battery -side and power supply to ICRM at the stater relay(hooks up to main positive post coming from the +side at the relay).

Bad or partially clogged radiator. Temp will just go up and the water will boil out of the overflow. Wish they made a mini-me plunger that mounts or the filler neck.....Hmmm...

Similar situation if the T-stat is bad.

Pump impellor could be FUBAR. Can't see the impellor but the water will be nasty brown and thats an indication of your innards.

Could be air bubble and not that uncommon. Loosen the bleed bolt(above the T-stat and let it blow some stuff out)
Good luck.
 
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Update

I played with it a little today. I pulled out the bleeder screw and filled it up and ran it withthe cap off. I kept letting the air buble out. I pulled the plug on the fan so it stayed on. The car heated up and I kept opening (slightly) the cap to let the air out. It was running a little hot and then it would cool down when I reved it to about 2000 R's. The heat would come on and off with the temp guage, When the guage was hot the heat was cold, when the guage started to come down, it blew heat. I think the impeller is slipping in the water pump. anybody else?
 
Could be a bad pump. Disconnect the upper hose and see, just keep filling the rad.

More than half the time someone has your symtoms it's just low on coolant. You will need to bring the car to temp and have the bleeder closed and the rad cap closed. have the overflow full and walk away. After it cools and sucks in water it should be fine. Try that a couple of times. If that doesn't work then look elswhere.

Jeff
 
Kitty runnin hot!

I kept adding coolant, I'll mess with it more tomorrow. Somebody told me that the Charger could be pushing air into the coolant jackets if the Head Gaskets are shot causing the bubles in the fluid???? Sound right??? I played with it for a while today and it seemed like there was alot of air. I figure that the Water pump could've puked a seal and is pulling air into the system. I'm really at a loss. I guess I'll put a pump in it and see what happens. any one else got any ideas?
 
Well the SC isn't going to "put air in" on moderate driving, since the engine is operating under vacuum 95% of the time. Bubbles in the rad could indicate a blown headgasket, but you need to do a compression check b4 you start throwing parts at it. It really sounds like your low on coolant.

Resist the urge to pop the cap all the time. Do as I posted earlier. Fill the overflow with coolant, run the car until it gets hot and shut it off. Come back after an hour or so and do it again. To get the temp up quicker run it around the block with your foot in it and then park it (shutting the engine off).

Jeff
 
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