I have a 94 formula that keeps overheating and losing coolant. Yes, the air dam is on and the water pump is working. I can hear a quiet hissing sound near the passenger head and am wondering if the head is warped or if a freeze plug got loose. Any Thoughts?

 

bump.

 

Do a compression test on all of the cylinders on the passenger side. I doubt it would be a freeze plug, that would leak fast enough to find it and would leave puddles all over your garage floor.

 

thanks illl try that but whats the normal psi per cylinder for a newly rebuilt LT1?

 

Mine would hold pressure even with a blown head gasket FYI

That is what I am thinking here.

 

2fastforLV what was the psi and what were the cars sypmtoms?

 

also i found out its bored .30 over and had "new heads" assembled installed.

 

There really is not a specific pressure you are looking for, just check them and see if there is one that is quite a bit different than the others. You may want to test all 8 cylinders just to get a good average of what the pressures are. But if it still holds pressure as posted above you may have to pull the head to find out. How much coolant is it using? And was the system properly filled and the air bled out of it?

 

well thats been a concern of mine and i've tried to air bleed it but it doesn't seem to have fixed the problem; also what are the proper procedures to air bleed in case i was doing it incorrectly?

 

When i did mine i started the car then opened the bleeder screw and waited until a steady stream of coolant cam out then closed it back up and waited for the thermostat to open and repeated the process just to make sure there was not air in the coolant passages of the block. i am not sure if that is the "right way" to do it or not but it worked for me.

 

You may want to check your heater core hoses and your cross over tube for the heads.

 

Take it to a machanic and have him pressure test the cooling system.

 

I agree the cross over can dump alot of coolant, so can the heater core and connections

 

a coolant pressurs test can tell alot, it is a pump that is connected to a radator cap that applys pressure to the system and usually shows a leak

 

Well I thought that a head gasket might have blown or perhaps even a warped head, Ipressure tested the cooling system and made sure the needle didnt spike when it was running then I flushed the system, which was probably 90% water and replaced it with fresh coolant 50/50, system was air bled and i also replaced the water pump temp sensor. I started the car and and let it run for approx 20 min, it got up to about 240 and then the cooling fan came on and dropped it down to 210 or so. I dont know why the fans wouldnt come on at the 225 mark but did at the 240. Ive checked the relays but I have a suspiscion it might be the PCM or the settings for my fan. I DONT want to hard wire my fans to ignition because I want it to work correctly. Anyone Have any more ideas

 

also Its not losing coolant anymore it must have been the fact that it was mainly water and was just boiling and evaporating after 212.

 

bump.