1988 Engine Spraying Coolant
kbert
08-26-2005, 01:40 AM
I have an 84 mustang with an 88 5.0 engine in it. There is a new fan, new radiator, new water pump, and new thermostat. The car starts strong and idols for 5-8 minutes with no problems. Both the output and return coolant tubes (to and from the radiator) stay cool to the touch. Then the return tube (Drivers side tube running to the bottom of the radiator) begins to get hot, and that side of the radiator begings to get hot, while the output side (passenger side) remains cool. 1 minute later, coolant starts spraying out of the overflow with a great amount of pressure, and both tubes instantly get boiling hot. Running the car with the cap off causes coolent to start overflowing out of the radiator fill port (where the cap would go) even during initial idol. Does anyone have an idea what my problems is? Is it the head gasket?
Thanks Allot
- Keith
Thanks Allot
- Keith
kmathew
08-26-2005, 12:18 PM
I have an 84 mustang with an 88 5.0 engine in it. There is a new fan, new radiator, new water pump, and new thermostat. The car starts strong and idols for 5-8 minutes with no problems. Both the output and return coolant tubes (to and from the radiator) stay cool to the touch. Then the return tube (Drivers side tube running to the bottom of the radiator) begins to get hot, and that side of the radiator begings to get hot, while the output side (passenger side) remains cool. 1 minute later, coolant starts spraying out of the overflow with a great amount of pressure, and both tubes instantly get boiling hot. Running the car with the cap off causes coolent to start overflowing out of the radiator fill port (where the cap would go) even during initial idol. Does anyone have an idea what my problems is? Is it the head gasket?
Thanks Allot
- Keith
Aright KBERT:
I would check for blown head gasket first. Check your oil dipstick, if you have coolant in your oil or oil in your coolant or carbon debree in your coolant you have a blown headgasket. Replace both head gaskets.
The other possibility is you might have an air pocket in the engine. Sometimes when you replace everything as you've described the majority of the coolant will drain out of the engine. When you refill the radiator and start the engine it begins to heat up It reaches the temperature that your thermostat is rated at and it opens up, but there is no water in the block and no water in your water pump.
Now you have a situation where the motor is getting extremely hot, the thermostat has just opened up and starts to allow cold water into a hot block and it immediately changes it to steam. That blows through your engine and out your bottom hose back into your radiator and out your overflow. Thats really bad becausecold water on a hot block could crack it.
The solution is.
Remove the thermostat, reassembly the housing. Pull the top hose loose at the radiator and pour water into the hose until it backs up and over flows from the hose. This will allow you to get water into the block. Put the hose back on and start the engine. with no thermostat the water pump will immediately start pumping the cold water through the engine and it should heat up to normal temperature. Watch your temperature gauge inside your car. Turn the car off, let it cool down and replace the thermostat.
Now when you start the car there will be water in the block and not air.
If the problem comes back with the thermostat in place then your thermostat is not opening up and needs to be replaced. I know you said it was new but it could be bad. To check it put it in a pan of boiling water and see if it opens up. If it does it's OK if not replace it.
That about covers it. Try those and see what you have.
Good Luck
Kent Mathew
Dallas, TX
Thanks Allot
- Keith
Aright KBERT:
I would check for blown head gasket first. Check your oil dipstick, if you have coolant in your oil or oil in your coolant or carbon debree in your coolant you have a blown headgasket. Replace both head gaskets.
The other possibility is you might have an air pocket in the engine. Sometimes when you replace everything as you've described the majority of the coolant will drain out of the engine. When you refill the radiator and start the engine it begins to heat up It reaches the temperature that your thermostat is rated at and it opens up, but there is no water in the block and no water in your water pump.
Now you have a situation where the motor is getting extremely hot, the thermostat has just opened up and starts to allow cold water into a hot block and it immediately changes it to steam. That blows through your engine and out your bottom hose back into your radiator and out your overflow. Thats really bad becausecold water on a hot block could crack it.
The solution is.
Remove the thermostat, reassembly the housing. Pull the top hose loose at the radiator and pour water into the hose until it backs up and over flows from the hose. This will allow you to get water into the block. Put the hose back on and start the engine. with no thermostat the water pump will immediately start pumping the cold water through the engine and it should heat up to normal temperature. Watch your temperature gauge inside your car. Turn the car off, let it cool down and replace the thermostat.
Now when you start the car there will be water in the block and not air.
If the problem comes back with the thermostat in place then your thermostat is not opening up and needs to be replaced. I know you said it was new but it could be bad. To check it put it in a pan of boiling water and see if it opens up. If it does it's OK if not replace it.
That about covers it. Try those and see what you have.
Good Luck
Kent Mathew
Dallas, TX
Automotive Network, Inc., Copyright ©2026