In 84 or 85 Ford changed to a bottle with the hose coming in from the bottom. They will keep the system completely full better, in my experience, than the one with the hose coming in from the top. That's why I use the later ones on my 81's.

 

I would rather it suck coolant from the top, because the bottom of the overflow container can accumulate crap.

Makes me wonder what the PSI rating of the radiator cap is; if it's letting loose too early, the system won't build up pressure like it's supposed to.

 

What's a normal cap rated at?
13 psi?

 

It's either 13 or 16 but I forget for certain.... IIRC most Fords are all the same but I forget what that rating is; a shop manual should have it, maybe the owner's manual, or just look online at a parts place and see if you can find it described somewhere.

 

The 84 shop manual I have says 13 psi.

 

Yep, mine are 13 psi. And, btw, I don't put crap in my overflow tank. Nor my heating system. So if it is gathering there maybe it is time to clean it?

Seriously though, I do find the ones that suck out of the bottom to work much better. I like to keep the cooling system completely full, and the bottom-draw ones do that better IMHO.