my hmmwv is spitting out antifreeze!?

Question

I have a humvee that WAS overheating. It would sound like it was sucking in air through somewhere. I did a pressure test on the radiator cap and it only held 7lbs of pressure. I changed the cap and removed the thermostat. Now it's not overheating, but it is still sucking air. The problem is, when it starts to heat up (not overheat), it spits out coolant through the over flow tube. Then runs out of coolant/water, then overheats. Can anybody help me with this problem?

Answer 1

Hoses are (Softer then normal when warm, they could be bad internally) bad and need replacing. 7Lbs test Pressure, way to low, should be 12 to 15. Radiator/Engine may need to be boiled/Flushed out! If you removed the thermostat (Didn't replace it, Why?) and it's still overheating you have a restricted system, boil/flush ASAP. With the low test pressure you do have a pressure leak somewhere! Air sucking sound could be "Bad Intake Manifold Gasket, Sucking air at water pump, bad air compressor, Etc.

Answer 2

There's a major problem somewhere in your cooling system. 7 lbs. doesn't cut it. The system should hold a bare minimum of 15 psi. (or the number stamped on the correct radiator pressure cap) overnight.
If it's still under GM's warranty you'd better start screaming. Anytime a cooling system looses or pushes coolant from the coolant recovery bottle there's a compression (head gasket) leak or a cracked cylinder head.
If the heads do need to come off it's best to have them checked for flatness and dye checked for cracks at an automotive engine machine shop. Most have either Zyglow or Magniflux capabilities to ferret out any irregularities in the metal.
I'm sorry but I've never heard the term "sucking air" in reference to cooling systems. The only thing I can think of is the noise of coolant actually boiling inside the radiator and block.

Answer 3

when you remove the thermostat ,you will be using 10 %
more gas than before ..

I asumed you pressure test the cooling system too,and did not find a major leak, There is a small leak ,keep looking.

If youre positively sure that there is no leak,Fill up your cooling system to the rim ,dont put the cap, run the engine and observe ,keep puting water to make sure ther is no air in the system,and it is full.,,,there should be no air bubles present after running for 5 minutes,,,if threre are air bubbles
double check repeat the process because you have a major problem if there are bubbles,,,your head gasket is leaking
causing to spit out coolant,when there are more pressure in the system

if you have a pressure tester ,leave it connected and observe
the pressure ,,

there are some other test ,they will test for gas in the cooling system ,ask for it when you bring your car to a shop and they will check if your coolant is going around at the same time,to make sure you dont have a restriction in your system

tito

Answer 4

Try doing a pressure test on the cooling system and see if you can pin point where the noise is coming from. There might be a problem with the radiator. It is hard to say. I would try testing the cooling system first. Usually if your cap is bad the hoses will collapse. Good luck.

Answer 5

it sunds like ur water pump isnt working remove the hose to the pump and c if its moving the coolant have u had any work done to the cooling system

Answer 6

check water pump . do a radiator flush .

Answer 7

you could have a hole in you radiator hose or you have a blown head gasket.

Answer 8

yup! herd them thangs sucked. so tell me again how you removed the thermastat.so,s my brother can hear,he was thinkin bout doin a apindickinme on grandma!!