94 3.1 trouble bleeding air out of cooling system

[turbotim23]

Hi I have a 94 corsica with a 3.1. When warm the coolant pushes out of the top of the coolant bottle if open. This isn't normal is it? I always thought that was sign of a bad head gasket and exhaust gas getting in to cooling system. The thing is I've tested it with my coolant pressure tester,the pressure does go down slowly but will still have pressure left on tester even if left all day and also over night, Changing a head gasket is too big a job to just do it. I have to be sure it really needs it replaced. I'm thinking having air trapped in the system might also cause this same problem. What do you think? Have any of you had problems bleeding the air out of the system? Some of these cars have a air bleeder on the thermostat housing mine just has one on top of water pump.I'm thinking of adding one to thermostat housing. I also saw something a while back about drilling very small holes in the thermostat itself to help bleed air through it. Anyone know anything about doing that? thanks

[Purple pit]

Have you replaced anything in the cooling system lately? If so then you need to bleed the air out.

Are you opening the cap when the engine is hot? That should make coolant flow out as the system is under pressure. Checking the level should be done with the engine cold. That is why the tank has mark on it that says cold level.

[turbotim23]

Have you replaced anything in the cooling system lately? If so then you need to bleed the air out.

Are you opening the cap when the engine is hot? That should make coolant flow out as the system is under pressure. Checking the level should be done with the engine cold. That is why the tank has mark on it that says cold level.

This a cold start with bottle top off,when warm it gushes out of remote bottle[the only fill spot on this system]. I did replace the timing gasket, I filled it then pressure tested it for other leaks. I fixed a couple I found then drained it to refill with a snapon coolant refiller, this puts system under vacuum to draw air out and draws coolant back in under vacuum. I relied on it to keep air out. Shouldn't be any air in there but I will try normal air bleeding also. I also bought a exhaust gas coolant tester , the kind with fluid that changes color if exhaust gas is in cooling system. With coolant bottle empty the bottle filled so fast with coolant I didn't have enough time for tester to tell if exhaust gas was getting in coolant system. Thanks for your help

[Purple pit]

I can see why you are stumped. Getting there myself. Sucks not having a radiator cap(I know, my system is the same). The lazy way to bleed is to start the car, let it run without warming up and shut it off. Then open the cap. If there is air it will chug and draw coolant out of the tank. Do this a few times and then take it for a drive. Let it warm up all the way, if the temp shoots up before it takes the normal time to warm up there is still air in the system. If you get scared turn the heater on(that acts as another radiator). Really the heater should be turned on anyway because it may still have air in it.

Again that is the lazy way, but it does work and keeps the coolant in the system. Using the bleeder spills it.
I'm sure there is a "normal" or correct way to do it. I've just always done it that way. Keep in mind I'm a bit old school and still miss having the cap on the radiator.

[Superdave]

I always had problems with burping my 60v6's.. On my old stock 3.1 it kept getting air in the system, turned out that I had a crack in one of the plastic lines on the heater core. After replacing that I took it in for a professional flush and it was fine for years till I pulled it out for the 3400.

[turbotim23]

I always had problems with burping my 60v6's.. On my old stock 3.1 it kept getting air in the system, turned out that I had a crack in one of the plastic lines on the heater core. After replacing that I took it in for a professional flush and it was fine for years till I pulled it out for the 3400.

Yes having more leaks is I something I fear on this car,It looks like I'll never see the end of them on this car! It still loses pressure when I pressure test it but pressure leaks down very slowly over many hours. Getting sick of working on it and I think it's good enough to drive now so I'm thinking of just driving it and watching the bottle level very closely. This car isn't worth putting a lot of time into it but I was hoping to be able to drive it out of town with it on longer trips. Thanks again

[Superdave]

I drove mine across the country like that, it was fine until I'd shut it down at a rest stop and it would piss all over the ground. lol