Why cant I find where my coolant is disappearing to? I've tried a compression test, no leak~ I drive the car for a few day's after filling up the coolant system and it starts to over heat out of no where (I can tell when there's air in the coolant system). When I turn on the heater the car over heats.

After sitting for a while, the vehicle has a hard time cranking up. If I go to give her gas before she warms up, she hesitates. Other than all of that, the car is like a tank.

How can I stop this coolant issue, as well as the hesitation (strong gas smell??)??

 

I see gunk in the coolant reservoir, but again, there's no leak.

 

have a crack in the combustion chamber. You are going to need to have it pressure tested and they will find the leak.
Have you bothered to test for combustion gases in the coolant res?
Test strips are sold at most auto parts stores.