Hi my name is Bryan and although I don't own a jeep I am a pretty well versed mechanic and have worked and do work on a lot of different vehicles ,I'm currently working on a friend jeep grand Cherokee Laredo 1993 ,5.2 and it has an overheat problem that truly has me perplexed just driving me nuts I have performed a combustion leak test and it came back as clean (no combustion gasses in the radiator) but when I start it up it acts just like a cracked head or blown head gasket ,within just minutes of starting I'm already overheating and starting to run rough I've cleaned the radiator out ,I've pulled the water pump , replaced the thermostat and radiator cap and I thought air in the system but other than the air I can squeeze out of the top radiator hose that's the only air I can find ,I need input on this ,it really has me questioning my mechanical ability,any help would be greatly appreciated and added to my mechanical knowledge with gratitude,sorry about my lack of proper punctuation but I'm no scholar just a regular guy trying to get by in life.
