cooling problems

took my road runner for a short drive and it got up to 250* , came home changed thermostat same thing again , took therostat out , same problem , Its a 70 with a 383 pretty much stock, 26" rad that looks new , but noticed not much coolant circulating could the water pump go bad with out leaking??

It's rare for a pump to fail where it won't move water. Maybe the rotor fell off.

I guess you opened the radiator then warmed up the engine to see if water was moving?

Is the upper radiator hose getting hot?

Grab a temp gun and start looking for cold spots in the cooling system. That will show you where the water isn't moving.

partly plugged rad. I'm assuming there's a proper fan/shroud in place

RapidRobert ... you helped me out with my problem on my 340 last year.
It ended up being a worn pump shaft where the impeller would freewheel intermittently... I never thought it was possible, and it was the craziest thing to sort out, but in the end it was the easiest fix...

https://board.moparts.org/ubbthreads/show...rue#Post6857083

both hoses getting hot , has a recored rad a 7 blade none clutch fan , also has the shroud

Pretty easy to pull the WP and check it out. That's what I'd do next.

pretty sure I found the problem , the lower rad hose is collapsing as soon as you take the engine any amount above Idle, it sat and idled 30+min at 190* but climbed steady and fast when reving the engine. thanks for all the sugestions on where to look

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pretty sure I found the problem , the lower rad hose is collapsing as soon as you take the engine any amount above Idle, it sat and idled 30+min at 190* but climbed steady and fast when reving the engine. thanks for all the sugestions on where to look

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I had the same problem... I tried finding a lower rad hose that had the wire spring in it, and had no luck. I bought a generic upper rad hose in the same diameter that had the spring inside it, .. pulled the spring out, and put it in my lower hose.. no more collapsing hose