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OK, the coolant is not boiling when I run the car with the heat on, It hasn't registered hot but the coolant was boiling and leaking(running out)when the heat is not onAny suggestions?

 

There is a multitude of reasons for a car to overheat. Bad/clogged radiator, bad water pump, bad thermostat, etc. Where is the water running out from?

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Does the temp guage read higher with the heater off than it does with the heater on? As Karin said this can be caused by a number of things. If the guage isn't rising when you turn the heater off, until you've boiled off some coolant anyway, then I'd start with checking the cap. Look for any cracks or splits in the rubber gaskets. I bet the guage varies with the heater on or off though and I'd say the cooling system is probably plugged to the point that it can manage with the additional cooling effect of the heater core, but not without.

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Over heating sitting at a stop light?

Or out on the freeway at speed? Both?

Is the electric radiator fan coming on?

Does it only leak when hot? From the overflow?

 

More detail about when it over heats and when it doesn't will really help.

 

Gary

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Hi Gary, I like your cars!!! NOt overheating at stop light. I've been driving it yesterday with the heat on and the coolant stays cool but still fills up the overflow tank. The cap on the overflow doesnt't fit correctly either. The radiator fan, I believe, is coming on. No coolant out of exhaust or in oil. No other leaks. All hoses checked!? temp gauge not registering hot but was unplugged when I bought it. And I know it works. I'm(we) are going to figure this out! I know we will! Thanks for your response!! I'm not sure about leakage from water pump? How would I check that? And Not absolutely sure about fan either. Is ther only one fan? 1.8 1985 wagon. Gracias! Heather

Over heating sitting at a stop light?

Or out on the freeway at speed? Both?

Is the electric radiator fan coming on?

Does it only leak when hot? From the overflow?

 

More detail about when it over heats and when it doesn't will really help.

 

Gary

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A new radiator cap and thermostat are easy and cheap, but I’m not leaning toward them with the symptoms you describe.

 

The fact that it pushes out coolant without getting really hot does indicate a head gasket issue (as Cougar said). Try this check, with the engine cold, remove the radiator cap and make sure the coolant level is up where you can see the surface. Start the car and watch for bubbles coming up. As the car warms up the coolant level may rise and overflow a bit, don’t worry about that, what you are looking for is combustion gasses being forced past the head gasket into the cooling system. No bubbles or water/oil mixing and a compression check should rule out a bad HG.

 

Cars need more horsepower to go faster, and so need more cooling capacity, overheating at high speed is an indication of inadequate cooling. If it runs cooler on cool days and hotter when its warm out or the heater help keep the coolant temps down the radiator is the number one suspect. Try this check, with the car up to temp, turn the engine off, pop the hood and feel the radiator core, careful not to burn yourself (this can be tough if the car has A/C). Feeling left to right is less important than top to bottom, if any part of the core is significantly cooler than another the radiator is likely plugged. The bottom tubes are most common but the radiator in my wagon was dead cold over 75% of the middle and hot on the top and bottom 2 or 3 tubes.

 

Water pumps don’t normally stop pumping, leakage is there typical failure. Whether gasket or shaft seal, a water pump leak will be at the front of the engine, just left (driver side) of center . And will normally leak some all the time, more when hot and under pressure.

 

Gary

 

P.S. thanks for the complement on the cars. :)

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hi ive just had the same problem as you have discribed apart from the water leaking , i replaced the thermostate and raditor cap and bleed the air from the system , it takes ages but it wrked fine for me

 

good luck

 

95 legacy 250T

OK, the coolant is not boiling when I run the car with the heat on, It hasn't registered hot but the coolant was boiling and leaking(running out)when the heat is not onAny suggestions?
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