Strange Coolant Leak

I have a 95 xj. Today i noticed a small leak of coolant while warming the rig up. I found where the leak is coming from...there is a small 3 way plastic pipe where the heater core (i guess) hoses get attached and one hose to the rad. Attached to that pipe is a small circular (about the size of a film canaster) piece with a wire coming out of the top of it. This canaster is attached to the pipe via two small screws...the coolant is leaking out of the bottom screw but only until the engine is warm and doesnt leak when the jeep isnt running...anybody know what im describing here??? I dont know what this small canaster is??

THX

I believe that would be the bypass for the heater core. That canister is a valve that allows coolant to flow to the HC when you have the heater is on and bypass the HC when the heater is off. The 'wire' coming out the top is a vacuum line that actuates the valve.

karstic said:

I believe that would be the bypass for the heater core. That canister is a valve that allows coolant to flow to the HC when you have the heater is on and bypass the HC when the heater is off. The 'wire' coming out the top is a vacuum line that actuates the valve.

Click to expand...

thats it!