Engine Cooling Advice

[1987 GMC Jimmy]

Hey, folks. Been a busy weekend, but I came straight home from school to piddle with my stuff. I don't have enough time to wade into the Jeep mod so I decided to try to make my Caprice run cool like it's supposed to. My heater core was busted at the top so I replaced it yesterday. It was corroded and full of rust, scale, and dirt, too. The car overheated a week ago, and it diesels when it's running warmer than it should. It still did, although not as bad. I flushed the cooling system because I was worried all that filth and rust could have dislodged itself out of the core and could have been blocking something. The radiator would burble coolant out if it was ran with the system open, and the lower hose was cooler so that was my secondary motivation. It's one of those newer type radiators, and now the stupid little plastic petcock won't seal. I'm going to get some thread sealer and try it, but if it doesn't work, I'll assume the threads inside are stripped. Any experience with this or suggestions? My thermostat is opening up, and I'm assuming the water pump is fine because there isn't any water leaking, and there isn't any noise from the pump. Plus, the upper hose is getting nicely hot and so are the inlet and outlet hoses for the heater.

 

[Camar068]

Saw a bunch of plastic radiator repair video's on youtube a while back. Not sure if any of them were specific to the petcock though.

 

[1987 GMC Jimmy]

Removed the radiator and fixed it. No leaks anywhere and fresh fluids. However, I think I got water somewhere it didn't need to be because I have a miss that'll come and go, and I actually turned the key and it turned over a few times and everything went dead. I dried the crucial areas near the radiator and let the car rest. Hopefully I can relish in the fruits of my labor tomorrow.