LS head gasket diagnosis help

[skylark]

We bought a 2000 Suburban with a 5.3 knowing that it had a blown head gasket. They had just put a water pump on it and the shop had diagnosed it as a bad head gasket after the water pump. The radiator is cracked as well. it was definitely putting air in the cooling system and pushing out water.

It idles with a slight miss but really not that bad. My scanner isn't picking up any misfires. A compression test shows even compression. When it is cold it will warm up without putting any air into the surge tank. If I just fire it up cold and drive it to work which is about 5 miles it will push 2 gallons of water out of the system. If I fire it up and let it warm up then drive the same distance it goes through less than half a gallon. I know that it could be the metal expanding to make it seal somewhat better but it doesn't seem like a gallon and a half difference would be possible with metal expansion. The thermostat is opening and closing properly. I did notice that the steam vent line to the radiator doesn't seem to be as warm as the radiator hoses and lines to the surge tank. The oil is fine, it is not milkshake.

I really feel like I am missing something here even though I was solid in my diagnosis initially when seeing the air in the surge tank.

I wouldn't be driving it except for the fact that I had to loan a daily driver to my dad because his piece of crap Ford broke again. He drives 30 plus miles one way to work where I only drive 5.

 

[BIG_KID]

GM MLS head gaskets are pretty stout and even the aftermarket won't compair in reliability. I've heard of every other problem with the LS engine but very few blown head gaskets, but those were due to snapped off head bolts. The stock head bolts are TTY

Did you do a combustion leak detector test in the radiator ?

 

[skylark]

GM MLS head gaskets are pretty stout and even the aftermarket won't compair in reliability. I've heard of every other problem with the LS engine but very few blown head gaskets, but those were due to snapped off head bolts. The stock head bolts are TTY

Did you do a combustion leak detector test in the radiator ?

Unfortunately I don't have the tools to do the combustion test. What I am going to do is pull the spark plugs and air check the cylinders one at a time and see if bubbles pop up in the surge tank. Probably be a week or two before I can get to that though. I won't be driving the Suburban more than another day or two though so I'm not too worried about it.

 

[BIG_KID]

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I wonder if this is part of their tool loaner program