i recently found out my cap was rated at 0.9 psi and i looked up oreillys and the oem is 13 psi its not running hot but losing a little water and not getting any suction out the reservior could this be why my heater aint getting reaaly hot and could it possibly have damaged any gaskets

 

I have never really paid attention to the caps psi rating, so cant help you there. I would pull the hoses at the firewall and flush the heater core. Also make sure your cable is actually moving the control valve. They tend to freeze up.

If the valve is frozen, I think there is an upgrade by using a 2nd gen runners control valve which is better built. I havent done this upgrade yet, but hear it is just a matter of swapping valves.

 

i have flushed it several times and the valve is opening its warm but not hot it will warm the truck with fan on low but on high it gets cooler

 

That might be the suction/vacuum value. Can't say I've ever seen one that low otherwise.

Your water will boil/steam off faster, about 200-212 down in MS, instead of the 260+ it's designed for.

The not sucking water back in means the outer gasket has failed, wrong size worn out flange or just old and shrunken.

 

PS. make sure you're looking at the PSi not BAR rating 0.9 BAR is 13PSI

 

ok thanks ill look at the cap and see wat it says

 

wat else could cause the pressure or is it normal its not running hot i had it tested with a therm and it read around 180

 

If you're boil of water at 180, the cap isn't sealing and the thermometer is inacurate or there are much bigger hills in MS than I know about

 

its not boiling but the cap was a 1.1 i put 13 on it today and my heat works better and gauge stays at a quarter