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97 cobra keeps getting air in cooling system but passes combustion leak test

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97 cobra keeps getting air in cooling system but passes combustion leak test

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Old 06-06-2017, 07:35 PM
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lucky2spot
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Question 97 cobra keeps getting air in cooling system but passes combustion leak test

Can a head gasket leak put clean air into cooling system making it pass combustion leak tests?
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Old 06-07-2017, 06:51 AM
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88 orangepeel notch
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Yes, a bad head gasket can pressurize your cooling system, but not with clear air. You'll see black, sooty slime in the coolant usually.

Your local auto parts store should have little test strips that you dip in your coolant telling you if hydro carbons are present, meaning you have a head gasket going bad.

Good luck and welcome to the forum.
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Old 06-07-2017, 04:59 PM
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dawson1112
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Originally Posted by lucky2spot View Post
Can a head gasket leak put clean air into cooling system making it pass combustion leak tests?
A head gasket leak into the cooling system will over pressurize the coolant. Look for bubbles coming up into the reservoir especially when revving the engine.

If it was a head gasket , you would get hydrocarbons in the coolant and a block test kit will show that.

Do a compression leak down test, if each cylinder will hold compression then I would look to see where your coolant is going. It is most likely leaking the coolant someplace, if you dont have drops of coolant on the ground under your car its very likely that the intake is leaking coolant into one of the cylinders.
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