I was told I have a blown head gasket but these guys just seemed so unprofessional and would not answer any of my questions. So I’m wondering can it be a blown head gasket if there is no coolant leaks no misfires no white smoke. The only symptom my car has is it overheats when the car warms up when I stop the coolant in the overflow tank is boiling or bubbling. When they ran tests the said there was combustible gases in my coolant. Thank you.
If you are uncomfortable with the mechanic shop you took your car to, exercise your right to take it somewhere else. A compression test is a good place to start when diagnosing a blown head gasket.
A pressure gauge can be installed to the cooling system to detect excessive pressure. Most cooling systems pressure is under 20 psi. When engine cylinder compression enters the cooling system the pressure gauge would spike and exceed this amount. An engines compression in each cylinder can be 100 psi or more.
Boiling coolant usually indicates a poor mixture. The coolant to water ration should be 50/50. Straight water will allow the engine to overheat quickly. So if the cooling system has been worked on recently and just topped off with water, it may be the cause.
When the cooling system is low on coolant it will overheat as well. If this is the case, finding the leak and repairing it would be the best course of action.