I have a 68 Nova and since we've owned it, there's always been a problem with an antifreeze leak. The last 3 times it was driven, once it gets up to 190 or so, a drip starts and when the car is turned off coolant just blows out all over but we can't tell where from. The underside of the car is wet everywhere from blowing back while driving. Today, I turned the car off and the lower radiator hose blew off the engine and every bit of antifreeze blew out everywhere. Tell me this isn't a head gasket issue. We've changed all hoses and just got a new thermostat but haven't put it in yet. Any suggestions? Thank you.

 

Hi, You need to start by pressure testing the system ( make sure system if full and isolate and repair the leak. If no leak was found then monitor pressure gauge to see if there is a loss of pressure if you find a pressure loss (without an external leak) you could have a head gasket or another problem such as a cracked head either way the head has to be pulled and inspected. If every thing checks good replace the thermostat and refill and purge cooling system, don't forget to pressure test radiator cap to make sure it holds pressure if not replace it What engine is in this car and is it equipped with a coolant recovery bottle and a fan clutch? If it is not equipped with a recovery bottle install one. With system purged the coolant should be at hot or full level when hot or low, min level when cold.

 

Thanks for the info. We will be doing the pressure testing over the weekend. It's got a 350 in it but the previous owner did some tweaking to it so we're working on someone else's project and we're not sure what exactly was done. There is an overflow bottle and it seems to be doing it's job. The other thing that made me think it could be a head gasket issue....I started it up after replacing the hoses and before putting the radiator cap on and it blew out of it, spraying excessivly from it. I know from past experiences that this usually means something worse. Appreciate the help!

 

Hi, I would deff replace the thermostat . When you refill the cooling system use a purge funnel it helps a lot to rid system of air it also allows you to see if water pump is moving the water in the system at a good rate depending on rpm's if water pump is bad it could be your problem as well. Good luck and let me know how it turns out.

 

Did you try a new radiator cap? Put in the new thermostat and new radiator cap and try that. If that doesn't work, fill the radiator and leave the cap off and start engine, let it get to operating temp and look into the radiator. if there is a constant stream of bubbles then you have a bad head gasket.

 

I wanted to update the thread. We did the pressure tests and everything was great after replacing the radiator hose. We also found out that the timing was causing all the problems. It was so far off, that once it was adjusted, everything seemed to just work and run smoothly. The guy that adjusted it for us said it very well could have caused overheating and too much pressure. Seems like we lucked out!