same 99 montero (gen II.5 montero).

after engine is hot, shut off, and then starts cooling, the lower radiator hose starts collapsing on itself as if under intense vacuum pressure. I am not a cooling system expert, but I don't think it is supposed to do that is it? I thought it is supposed to suck coolant back into radiator from overflow bottle but it doesn't appear to be doing that.

I have a brand new mitsu t-stat, brand new mitsu radiator cap, brand new mitsu overflow bottle, what gives???? also, I was looking at the rad cap, I understand how it pushes coolant out into the overflow tank, but I can't understand the physics of the cap that allows coolant to go back into the radiator from the bottle; anyone know how it does this?

lastly, I did check the tube from rad neck to overflow bottle and it is not plugged up.

what gives???

97 Montero SR w/Mitsu Adj Shocks & Rear Diff Lock ARB Front Diff Lock 4.9 Ring/Pinion 3.15 transfer box 43:1 crawl ratio 2" suspen lift 2" body lift 2" Gas Tank Lift 35x12.5 MTRs 15x10 Wheels Rock Sliderz ARB front bumper w/12k winch Custom rear bumper