Skip the auto shop - Our mechanics make house calls

Q: Is this problem the thermostat or blown head gasket?

asked by on

I was driving down the road and my check gauges light came on. I pulled over and my radiator cap was sitting loosely (radiator cap blew off) . It would crank back up (barely) but had a rough idle. I had it towed back to the house. I drained my oil and antifreeze and neither have water or anything abnormal. My buddy said head gasket and another said thermostat. Please help me determine

Hey there. Test to see if the head gasket is blown the cooling system will need to be pressurized using a cooling system pressure tester to put pressure on the cooling system to see if it holds pressure. If it does not hold pressure and no external leaks are found then the head gasket is leaking. If no leaks are found the a combustion leak check can be done by using a coolant tester that is held on the radiator opening with a special liquid in the tester that changes to a blue color if engine combustion gas is getting in to the cooling system. This would indicate a head gasket leak or cracked cylinder head. If both of these tests are okay then test the radiator cap and replace the thermostat. If you need to have this looked at by a professional, a certified technician from YourMechanic can come to your car’s location to inspect the potential overheating issue.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Radiator fan cycles on once then never again

The cooling fan resistor if near the cooling fan connector on drivers side. The replacement of the high pressure switch for the a/c may fix the fan coming on with the a/c. Have the system computer scanned for codes and...

Q: I need antifreeze and it looks like it's red, napa sold me green will it hurt to mix

Hello. The only antifreeze that should be used in your car is that specified in the owner's manual and if not specified there, consult the OEM Factory Service Manual. The consequences of mixing "different" coolants together - and different colors...

Q: temperature gage going from 4 to 5 natches ,but car running ok

Hello. It is common for the temperature gauge to climb as the engine is warming up. It should sit at about the half way point and remain there as the engine runs. If it is fluctuating then you either have...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.