Hi I have a 1999 V70 station wagon with 110K miles. Driving on a hot day with the AC on, there was a load boom and the cabin was filled with steam and coolant flooded onto floorboards. The engine still had good power so I hobbled into a mechanic. His diagnosis after a cooling system pressure test was a blown head gasket, but he was not sure. Is it possible a coolant hose burst near the from so coolant came into the cabin, and not a head gasket problem? Any ideas would help. Thanks.

 

Your heater core broke, and leaked antifreeze into the car. And if you drove it far enough (does not take much) without coolant you could have damaged the head gasket. Or head gasket was previously damaged, your radiator cap pressure relief valve did not work and the pressure found the weakest part.

Disconnect the heater hoses from the firewall under the hood, block/clamp them off or connect them together somehow so the system will hold pressure. Then you can test for a blown head gasket. Or start the car and see if water (don't buy coolant yet, you may need it for your next car) will stay in it once the hoses are connected/blocked off.

However when a car has an extremely blown head gasket the coolant bottle has a distinct smell, and with really bad ones the spark plug cover melt/gets deformed, worse on the exhaust side of the engine.

 

definitely an issue with the heater core or the hoses to/from the core - Volvos always run coolant through the heater core using blend doors to control the heat. With that said, you could still have an head gasket issue as the root cause for why the heater core/hose blew out. If the head gasket allows exhaust gasses to get into the coolant chambers you'd get very high pressure in the cooling system which can blow out the pressure cap or pop a hose. There's a test that measures HCs in the coolant to detect if the head gasket is leaking. Check with your tech to see if they did such a test.

 

Thanks much for your very thorough reply Hoonk. I will explore further with the mechanic. Boon

 

Thanks for your suggestion mt6127. Very useful brother. Boon