Cooling System Q

[kwikshifter]

I picked up an 86 longbed (350/350 combo).  It's been sitting a while and I've been fixing little things.  Has a cooling problem which may end up being a stuck thermostat. 

However the rad cap was bad and I noticed it says 15lbs pressure/ closed system.  The overflow tank is not stock.  Has a tube from the rad to the bottom of the overflow tank.  Also has a relief tube at the top and a vented cap.

Question is should I block the relief tube and put a nonvented cap on the overflow tank?  Or is it fine as is.  Thanks, Gary

Pic.....1. vented cap
         2. relief hose
         3. input from rad

[bd]

Question is should I block the relief tube and put a nonvented cap on the overflow tank?  Or is it fine as is.

Fine as is.  The tank has to be vented or coolant won't flow correctly between the tank and radiator.

[kwikshifter]

I'd hoped so.  It would force coolant to leak thru the cap.  Although I'd had the cap off a couple of times, I did not notice that the rubber ring inside was only half there.

[gunrac]

I'd hoped so.  It would force coolant to leak thru the cap.  Although I'd had the cap off a couple of times, I did not notice that the rubber ring inside was only half there.

I'd start with changing out thermostat and rad. cap. Pretty cheep reassurance knowing those 2 things are good to go.

[Irish_Alley]

you can get bad new parts.

[bd]

Why do you think you might have a stuck T-stat?  Did the radiator cap fix your problem?