I recently got my car out of the shop because it would not keep a charge and the mechanic repaired some wires in the dash connecting to the alternator that had broke. Since then my air has not been working(blowing hot) and before I put it in the shop the compressor worked fine and now it won't even cut on. The mechanic got under the car and touched the wires and it came on then. He put freon in car and we added coolant, air still blowing hot! It also has not been holding coolant and has ran hot twice. Check engine light just came on last night. There is no smoke, mixture in oil, or visable leaks. Also, radiator is new, compressor is new, radiator fan motor is new, and all fuses were checked and good. Car runs great no loud noises or anything just when you have driven it for about 35mins does it begin to run hot and after checking coolant I have to replace because it disappears. Help!
Try replacing the thermostat-not it do the following below: Have it block and pressure tested-do the block first to pinpoint a combustion leaking into the cooling system or a gas analyzer to sniff for hydrocarbons at the radiator fill neck.
Pressure test: do not do a pressure test if there's leakage at the headgasket this might cause coolant into the cylinders and lock it up or bend a connecting rod if cranked thereafter. The headgasket should be repaired before doing the pressure test.
If the block and pressure test passes check the following: Thermostat, Pressure test the Rad. Cap, Clogged radiator, Fan clutch, Radiator electrical fan, collaspe hoses, water pump.