1999 Saab 9-5 Blown headgasket or cracked head?

1999 SAAB 9-5
300,000 MILES • 4 CYL • FWD • MANUAL
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CMKOONTZ
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I have a 99 saab 95 turbo that I am trying to fix, the tank on the drivers side of the radiator blew out. The tank didn't just crack, it almost broke in half, just under the upper radiator hose. Before I replaced the radiator I checked the cylinder compression ratios and found #1 at 80, #2 at 65, #3 at 45, and #4 at 85. All cylinders held pressure and never leaked down like I thought would happen if the head cracked and over pressurized the cooling system. I went ahead and replaced the radiator, system hold pressure and oil shows no signs of coolant in it.
I have tried to start the car, but it will not run. It's sound like it's firing but it just doesn't want to catch and run on it's own. Will a cylinder still hold pressure with a blown head gasket or cracked head?
Dec 6, 2009 at 11:35 AM
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BMRFIXIT
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You have very low compression at least on 2 cylinders
compression gauges is designed to get the Max reading and a one way valve should hold the readings
cylinder leak test is done by placing tested cylinder at top cylinder and introducing metered air to it as you check to see where is the air leading from
Dec 6, 2009 at 4:45 PM
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CMKOONTZ
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Thanks, I just thought about that after I posted. If I use a cylinder air tap and my compressor, would I be able to measure cylinder leak down by looking at the pressure gauge on the compressor?
Dec 6, 2009 at 5:21 PM
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BMRFIXIT
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Need to regulator the air in or it will push the piston down
cylinder need to be at top dead cylinder
listen and check for air leaks in the oil cap ,exhaust pipe coolant system ,intake and throttle
Dec 6, 2009 at 6:49 PM