Hi, my 2005 trailblazer hit something (the driver still claims it was a blowout, but once i saw damage and the rim I knew better) The radiator hose connector (?) was broken, the guy using my car said he replaced it. I noticed it overheating right after I got it back. It had coolant in the overflow, and immediately when I took radiator cap off, the coolant started filling the radiator. Took about three minutes to fill radiator up. So was thinking maybe the cap was shot, and messing up the pressure needed to recirculate fluid back into radiator. But before I could go any farther with that, another friend used my car and when it overheated, instead of running heater and letting it cool down so she could remove cap and get coolant into radiator, she sprayed down engine and radiator with cold water and flushed all of the Dexcool out of overflow. Upon getting my car back, I noticed the light coffee colored oil. So now am thinking the head gasket needs replaced? Onstar says to check the variable valve timing and also the emission system. Any idea what i need to check on the vvr and if it would cause overheating/water leaking into oil. Needless to say letting my "friends" borrow my car is over. I appreciate any and all input. Thanks.