sc0braj

89 mustang gt

i've searched and i've narrowed my problem down to : 1. thermostat stuck closed. 2. bad waterpump.. 3. blown headgasket..

symptoms: overheats fairly quickly.. coolant starts bubbling in the resv. and spills out..

i was told there is "no heater core" in the mustang.. i've read about all these compression tests and leakage tests.. i dont have any equipment.. all i have is my car and my apartment since the divorce. damn

capri man

i would start with the thermostat since it is the easiest. put in a pot of boiling water and see if it opens. or just replace it and give it a try. good luck

jacksjb

I had the same problem in my '96. Ran hot really fast, turned out it was a head gasket. A seriously blown head gasket will make the car start idling bad when it warms up also. I also now just replace the thermostat whenever I flush the coolant, cheap $5 insurance.

Some water pumps are made to leak when they go bad. Another check for the water pump is to pull the belt loose and spin the pulley. If it grinds the bearing has gone bad. If it spins with no resistance at all the impeller has come loose and is not pumping water.

Timspony

...Could be a blown head gasket! FYI: Mustangs HAVE heater core's!!!

sc0braj

i was definately hoping it is not a blown head gasket... but it might possibly be because i replaced the thermostat today(old was bad) but it still overheats but not as quickly and not as hot..

i have a blower but no hot hair blows out.. oonly the air from outside

Timspony

...Perhaps you have an air pocket ^^^??

Chopper

If the coolant is hot when it starts bubbling then you might have a broken waterpump.It's not unheard of.
If the coolant isn't up to operating temp then it's probably a head gasket.
Usually when an engine overheats due to actual overtemp the coolant will come out extremely hot,usually at a high enough temperature to scald anyone standing too close.The water will continue to shoot out of the filler neck until it's all gone and the block is completely empty.A blown head gasket will blow the water out that's above the leak and then only exhaust will come out of the filler.The problem with using these as a test is the fact that the engine is put under a LOT of stress from running long enough to achieve the needed temperatures.You might also have heavy white steam coming out of the exhaust if the leak is a head gasket.
You might try draining the coolant and starting the engine and watching and smelling for exhaust coming out of the filler neck.BEWARE,a shot of live steam can also come out if coolant suddenly comes in contact with a hot section of the engine.
This is all shadetree stuff and the best way is to do,or have done,a leakdown test of the cooling system.A test like that only takes a few minutes and shouldn't cost anything or very little.The test is done by applying air from a handheld pump kinda' like a bicycle pump but it has a pressure guage connected to it.The system is pumped up to about 15 PSI and either the pressure holds or it leaks off.If it leaks off and no coolant appears on the floor the leak is internal.If it runs onto the floor you track down the leak and start the fixin' process.Depending on the location of an external leak,pulling a head might not be so bad.

BTW you might be able to rent/borrow a pressure tester at Advance or Autozone and do the testing yourself.The pump goes on in place of the pressure cap on top of the radiator and you just pump it up and see what happens.If the test turns out that the leak is internal,a compresion/leakdown test would be performed on each cylinder until the offending head is identified.Test all the cylinders to make sure that both heads aren't leaking because a car with that many years on the clock can have both gaskets fail due to age/corrosion.
Let us know how it turns out and we might have more ideas for possible fixes.

KNS1

Sounds like there is an air pocket after you changed the stat. You need to properly bleed the system. As far someone telling you no heater core, was it the last owner and it was bypassed? Look at the firewall just behind the passenger side valve cover a little to the right , are the 2 hoses going into the firewall or are they connected together? Have you checked your oil? sometimes a blown head gasket will leak into the oil..... or are you getting a lot of smoke out of the exhaust?
My advice...start with bleeding the system. Then when you are sure its properly filled run it up to temp with the cap off of the radiator looking inside you should see coolant circulating.. also the top hose should get warm/hot as the stat opens. If you dont see movement or the top hose is not getting hot then you water pump may be the culprit.
Good luck and keep us updated