Coolant top off

[Irish_Alley]

lol missed the "entire time" my bad. i was a little busy at work

[philo_beddoe]

Recovery canister and tube is good. Here is my cap. Do those arrows really have to line up as stated?

[zieg85]

Recovery canister and tube is good. Here is my cap. Do those arrows really have to line up as stated?

yes, those OEM caps are hard to push down and turn on the shorter radiators I know.

[philo_beddoe]

I tried a stant, didnt fit well.

[philo_beddoe]

Got a Murray brand cap from o'reillys. Looks close to the oem, 13 lb. oem was 15. All the new caps, that center piece turns. Not my current oem one.

[bd]

There are two styles of "closed system" radiator caps (image).  One style uses light spring pressure to hold the vacuum check valve 'closed' until cooling system vacuum (caused by coolant cooling and contraction) pulls the valve off of its seat, drawing coolant back into the cooling system from the recovery bottle (upper image).  The other style cap relies on gravity to hold the vacuum valve 'open' until pressure buildup inside the cooling system forces the valve closed (lower image).  The different style vacuum valves are just two different approaches to accomplish the same goal.  OEM caps are generally the positive sealing style (upper image).  However, some OEM caps and many aftermarket caps use the passive vacuum valve approach (lower image).

Back to the symptoms on your truck.  Sometimes the vacuum valve will stick closed either because the vacuum valve spring is too stiff (positive sealing style caps) or the valve becomes lightly vulcanized to its seat (both style caps).  Either way, the collapsing hose is probably due to an uncooperative vacuum check valve.  Your truck should use a 15-16 lb cap.

[philo_beddoe]

Thats a great diagram, thanks. Not sure my oem cap lb. but the one vile gave me is a 15 lb. will i be fine with a 13?

[philo_beddoe]

Oh, btw, the new oem look-a-like murray cap fits real nice. But have not started truck yet for the real test.

[philo_beddoe]

Oh, btw, the new cap works great. No more collapsed upper rad hose.