patpatnc

I am a fairly new member. I have a 89 RX7 with cooling system problems. After the engine is shut down for some time, the radiator hose shrinks up as if it is under a vacuum. I read one time that there is a way to bleed the air from the cooling system.
If anyone can help me with this, I would appreciate it.
Thank you

Mitchocalypse

iTrader: (2)

That's because it is under a vacuum. It gets really hot in there which makes coolant (I sure hope you don't have too much air in there or you have bigger things to worry about) expand. It's meant to do this. When it cools off, it will return to it's original state, and by contracting, causes vacuum. I'm sort of new to rotary land so take everything I say with a grain of salt.

I would personally say replace the hose. Might be old and a bit warn out. Never heard of this actually happening before. Definitely try flushing you're coolant though. Even if it doesn't fix the problem, you're cooling system will be happy. I think there is something underneath the front rotor that lets the coolant out, then fill it with DISTILLED water, and start up and let run. Do this maybe 2 or 3 times. To ensure no air is in the cooling system, it's suggested you unhook the coolant line attached to the throttle body. Fill up coolant. It will leak out but this is okay, When full, re attach it. Stock hose clamps are really convenient and easy to use.

Someone correct me if i'm wrong.

Autoteacher

Most radiators are connected to an overflow bottle. the rad cap is a two way valve that responds to pressure if the valve in the cap is stuck than coolant that needs to be drawn in will stay in the bottle. normally you should not develop a vacuum in a cooling system strong enough to collaps a hose.

now someone needs to let this newbie to RX7s know if they have overflow bottles or just a vent?

misterstyx69

iTrader: (142)

Ok,the car has a Cap to overflow bottle.
Cap contracts under pressure(heat),vents coolant and then Takes it back.Cap closes when cooling and less pressure is present in System(Shutdown and cooling off).
If the hose to the Coolant bottle is Screwy then the Coolant can't get sucked back in.
ALSO,if you are getting air IN the system After shutdown,I would lay a Bet that the Hoses are NOT sealed up(as in Clampled tightly).That would allow air to get Sucked into the system if the cap is closed and it is still on the "cooldown phase".
It is looking to fill the system as it Expelled hot coolant.When it cools Cool Coolant comes back in to take its place,,Cap Shut,,it will Still suck and it will suck AIR.