1997 K1500 5.7, new cylinder heads and gaskets, started and ran for a short while now wont start at all

[Russ B]

white smoke is steam.. did you inspect the block for crack or warping? I like to put a straight edge across the block at different angles. you can pull the head on the side that is leaking coolant into the block, clean the mating surface and put some rags in the cylinders,., if u cant see any obvious defects on the surface of the block, take some very fine baby powder and sprinkle it on the top of the block,, this is the old school method before magnaflux.. if there is a crack, you will see it.. best use for babypowder besides butt cracks..,. haha
If the block is slightly warped, u may be able to true it up with a ******* file and alot of elbow grease.. then maybe use a slightly thicker head gasket. u might lose a little compression but it is better than pulling the motor.

1989 Chevy K1500 5.7 110k blowing lots of steam/coolant out tailpipe. CH gaskets and intake looked okay, but upon reassembly smoke was much worse. Compression tests on both heads was 180 on all. Attempted leakdown test but had trouble getting TDC without air pressure kicking down the piston. Thinking either one or the heads or block is bad.

 

[Schurkey]

1989 Chevy K1500 5.7 110k blowing lots of steam/coolant out tailpipe. CH gaskets and intake looked okay, but upon reassembly smoke was much worse.

Exhaust system loaded with coolant. When all cylinders are running, the exhaust system gets hotter and starts to boil-off the existing coolant.

The steam on reassembly should clear-up. If it doesn't, or if you notice the coolant level dropping, you still have a problem.

Attempted leakdown test but had trouble getting TDC without air pressure kicking down the piston.

Common problem, easy fix.

Use the leakdown tester to find TDC. Reduce the pressure to ~20 psi. Plug it into the cylinder like normal. Turn the crankshaft a few degrees with a ratchet or breaker-bar 'n' socket. Watch the pressure gauge. When the valves are open, there's no pressure indicated. As the crank turns and the valves close, the pressure rises to whatever low value you've set it to. As you bump the crank in the normal direction, the piston comes up a little, the pressure momentarily increases, then reduces to whatever you've set it to. Bump the crank again, pressure jumps then recedes. Continue bumping. At very close to TDC, you bump the crank and the pressure jumps very little, if at all. The "feel" of the ratchet/breaker bar is different. And if you go too far, you bump the crank and the piston goes down--now the indicated pressure drops momentarily before recovering. Back the crank up ten or fifteen degrees and try again.

REMOVE THE RATCHET/BREAKER BAR and socket. Disconnect the leakdown tester from the cylinder, jack the pressure up to whatever is your "testing" pressure (FAA says 90 psi, most car-guys go to 100 so the math is easier) and perform the test like normal.

Thinking either one or the heads or block is bad.

Or there's still liquid coolant that hasn't boiled out of the exhaust system.

Keep an eye on the coolant level in the radiator.