Alrighty then, I've been through the parts manual and can't seem to locate a part number for the radiator cap. All I'm finding is 050866226AA CAP, Coolant Reserve Tank, which I noticed is the same part number a couple of pages later for the reservoir cap, the exact same description even. I know that a flimsy piece of yellow plastic won't hold pressure. So, does anybody have the proper part number for a good old Ma Mopar OE radiator cap for the 2006 Rams? I’ve got a Stant on right now, but it seems to not be letting the coolant be drawn back into the radiator. I’d rather avoid aftermarket parts; I have had a rotten streak with them failing in the last few years if they’re not OE.