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Old 09-06-2009, 06:31 AM
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Blown head gasket? Air in cooling system

Hello guys,
I need help determining what the problem is.
The engine is 305 Chevy in 78' Monte Carlo. Stock as far as I know.
I have no history of the car at all so I do not know if it has been overheated or have other problems.

The upper radiator hose is getting very hard after some 10-15 km of driving. I have lever on the radiator cap and when I lift it the pressurized air escape in the overflow tank and the hose get soft. After I close the lever and drive 10-15 km, the upper hose get very hard again.
The engine do not get hot according to the instrument panel, somewhere between 100 and 220, see pictures.

I made the following test. I put a funnel made of plastic bottle with rubber insulator instead of radiator cap. Fill the funnel with water and start the engine. See pictures.
When the engine is idling there is no air going out through the funnel.
When I rave the engine the water level drops and then return with some air escaping. See the video

I run the engine without thermostat right now because I flushing it.
There was the same problem with thermostat installed.

Does it mean I have blown head gasket?

Is there any other test I need to run in order to determine my problem?

Thank you for your help,
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Old 09-06-2009, 06:48 AM
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There is NO problem, you need more education on motors, here is a bunch of info to read,

Look on top of the cap it says its PRESSURE CAP, what else would you expect ?
When you put the lever up all the pressure is let out along with coolant and that would make it low, the hard hose happens when pressure builds which is part of the cooling process.
Ever use a pressure cooker ?
Put the thermostat back in, check the rad level when cool and do some reading.
Luv the smell of NITRO in the morning.
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Old 09-06-2009, 06:59 AM
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Hi 1BAD80,
Thank you for your advises. I am sorry if I panic in vain or I am paranoid about it, but I am in Bulgaria, Europe, and American cars here are extremely rare and not many people have experience with them. I just try to check everything careful in order not to broke something as I did with the automatic transmission
Thanks for your help.
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