Car Blew Heater Core Inlet Coolant Hose
 

So I was driving around and came to a red light. As I was stopped there, my car slowly dropped idle until it shut off entirely. Before shutting off, the oil light, battery light came on. I started the car up after 10 seconds of holding the gas pedal to the floor. I drove it for 20-30 seconds more to get it out of the street cause I knew something was wrong. White smoke was coming from the side of the hood, which I presume was the coolant hitting the hot engine and evaporating. So I pull it into a parking lot and look under the car to see green coolant on the underside of the car. So the hose that ended up blowing was the Heater core inlet hose that goes from the engine block and into the heater core. There was about a 4-5 inch gash in it. So all coolant was gone from the engine.

Never started it back up. Had to tow it to a shop down the street from where I was at. My main concern here is the head gasket. While waiting for the tow truck, the temp gauge in the dash was displaying normal operating temp, so I'm assuming that the car shut down to prevent overheating and that's why it took 10 sec to start it up at the stop light. But I never saw the temp gauge go to the red at all during the entire thing.

So can someone confirm that i should still have a good head gasket considering the car probably didnt overheat? When I took the oil cap off, there was white smoke coming from it, but I assume that was the oil getting slightly burned due to no coolant in the engine, hence why the oil light came on when the car shut off.

tldr;

My coolant hose broke, car turned off to prevent overheating, I started it up to get it out of the street for 30 sec, and had it towed to a shop to replace said hose.

The temp gauge never went into the red, so my head gasket should still be good. I need a definite oil change after the hose and coolant get replaced.

Just want someone to confirm my head gasket should still be good after all this...

Thanks and sorry for the novel!

Well, we had something similar happen with our 850 when it lost all coolant. THe temperature gauge never went into the red because THERE WAS NO COOLANT FLOWING OVER IT TO SHOW ITS ACTUAL TEMPERATURE!! The car overheated and blew the head gasket. It also warped the head, but the temp gauge stayed at a normal reading the whole time.

The best way for you to tell if you blew the head gasket is a compression test. OR you can fix the hose, fill it with coolant, start the engine and see if you get white smoke out the tailpipe, or bubbling in the overflow tank while running.

I wish you best of luck, but I think the reason the engine shut down was it overheated and shut it self down.......Hope I am wrong.

\Glenn

The mechanic that is fixing the coolant inlet hose said he fired up the car to move it in the shop and said it fired right up normally. So do you think that is a good sign the gasket isn't blown? Cause a blown head gasket would cause low compression and would be noticeable upon startup most likely?

Hard to say without a compression test and or checking the coolant bottle for bubbling. Did you or the mechanic see any white smoke out of the tailpipe while it was running?
That is a strong indicator of a blown head gasket as well.Ours fired up ok too, but had a lot of white smoke out of the tailpipe and ran a little funky. You may have gotten lucky. Pleae keep us posted.

Well, I got the car back today. There is no bubbling in the coolant reservoir tank at all and no white smoke out the back. In fact, I even rented an engine block tester kit from an auto parts store. I ran the test and the liquid didnt turn yellow so I think my head gasket is fine!

HOWEVER, there is an intermittent startup misfire issue with the car now. After starting it, there is misfires and the engine runs at very low RPM for a minute or two and then smooths out. It runs very well after it smooths out. So I think the plugs need to be replaced again after the whole situation. If that doesn't fix it, I'm not sure what will to be honest.

I'm just glad the head gasket isnt toast!

Good news! What I would do is replace the plugs with Volvo OEM plugs (these cars like them best) and also the plug wires, distributor cap and rotor. You can get tehm al for $100 or less online. Good news though that the head gasket is ok!