OK, here’s an odd situation that I’ve never seen before, I just put a new aluminum radiator in my GS along with the new TA timing cover and about a one year-old water pump. The car seems to heat up quicker than normal but it’ll get up to 200° and then hold there with the electric fans on. The odd part is the car can sit for 12 or 14 hours and I come back the next day. Everything is now cold, but the radiator is still pressurized where a few pop the cap that water comes blasting out of there. Any idea why this isn’t bleeding down or is this a good thing. it does it with the cap. It came with the cold case radiator as well as the old radiator cap. I had that has one of those bleed off lifts on top of the cap. Also, I’m running a gutted thermostat so I don’t believe that is an issue.
Try changing the radiator cap, and make sure that the line from the radiator to the overflow container is not obstructed. The only other thing that can cause that is combustion gases in the coolant. There are test kits for that.
I’ll get a different radiator cap today and maybe a test kit. But if it was combustion gases getting in and pressurizing it from a leak, you would think that after 12 hours, the pressure would bleed down.
I’m going to put a good 160 degree thermostat in it tomorrow and try to ensure the system doesn’t have any air in it. If it still acts up I may have to cancel my Bowling Green plans ☹️ while I could get the car into the lanes before it heats up I’m afraid of blowing a hose or lifting the radiator cap going down the track.
On a couple of occasions I have run into a situation where I thought the cooling system was full, but due to the closed thermostat it had trapped air. My solution is to drill a 1/32 inch hole in the thermostat. If it's a flat-mounted 'stat, it doesn't matter where you drill the hole. If it's a vertical mount, then the hole needs to be as close to 12 o'clock as you can get it. The air will escape, but the hole isn't big enough to have any effect on engine cooling.
Yeah I’ve done the small hole in the thermostat in the past but I always thought it went in the 6 o’clock position. But thinking about it the little bypass hose will let some water by. The hole being at 12 o’clock makes sense to vent sir
My thoughts go to the Nailhead in the Buchev. Both heater hoses attach to the engine below the thermostat, so if the cooling system is totally drained, there is no direct path for any trapped air to escape if the thermostat is closed tight. With the tiny hole, I can fill the cooling system until it will maintain the level at the top of the radiator, then put the radiator cap back on and fogeddaboudit. I will add a bit of coolant to the overflow, but it's not really necessary.
