high speed overheating

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cudaman51

cudaman51

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The faster i go the hotter it gets. i have a 3 core 22inch copper replacement radiator in exultant shape fan shroud rubber air dam on hood and 340 engine half filled with hard block.I am told my radiator is adiquit but its still heating up on hot days over 60mph. would a high volume pump help. I am thinking only at low speed. looks to me like i need more radiator. dose the hard block make that much difference.I WOULD Appreciate some advice on a solution. THANKS.
 
I am by no means a mechanic, but I was having the same issue on my car, and it was the water pump. When I took it out, I could tell that the teeth on the shaft had worn the housing. Once I replaced it, I ran at 190 on the interstate.
 
Do you have a fan shroud on it? I would think the block fill on a street car could be a problem.
 
if it cools at low speeds and idel I would think the water is moving to fast Thur the rad at speed I had the same with the wife's dart put a 195 stat in and car runs around 180 know. I haven't figured that one out yet.........Artie
 
7 Blade steel fan with jaguar thermal clutch and yes i have a shroud and good stock standard water pump
 
check to make sure the lower radiator has a spring in it so the hose doesnt collapse...if it doesnt you can rev the engine a bit and will see the hose collapse, and if thats not the problem like the other person said go to hotter thermostat to slow the water down
 
I know nothing about that fan clutch so I'm out. Good luck though
 
It's not airflow if it is cooling at low speed but getting hot at higher speeds.

Most likely it's tuning (overly rich or lean), coolant flow or coolant capacity (probably this because of the hard block)
 
That clutch is the standard thermal clutch just 1half inch shorter than stock mopar for clearance issues
 
How hot is it actually running? And are you confident that temp gauge is providing accurate readings?

Pat
 
One thing thats overlooked when a car is overheating is the carb. Lean engines run hot. I would fatten up the carb. Inexpensive and you've done everything else. Worth a try.
 
Have you always had the problem?

If the problem is new, i don't think carb tuning would be the problem. As mentioned a lean engine will run hot.

Radiator could be clogged...thermostat could be stuck...or a collapsed radiator hose (like mentioned above).

The other thing I would look at is the water pump.

I don't think "hard block" is a good idea on a street car...you reduce the amount of coolant in the cooling system and old cars aren't known for their wonderful cooling abilities to begin with.

Paul
 
I just put on a smaller pump pulley and it helped e little. i just ran 70mph for 10mi in 80 degree temp and it went up to 200. timing is 35 total. hose has the spring and temp gauge is accurate. radiator went to shop for flushing and they said nothing wrong with it. spark plugs look the right color.havent changed thermostat for a wile but it dose regulate to 180 quite well at low speeds. I gota get out the infare thermometer and play with it. I need a radiator for another car so i am tempted to buy it to try in this car.
 
My 360 was hard blocked all the way to the top It was street driven when I had your problem I found my top hose colasping. Mine ran warm 190-200 in town if I hit alot of red lights, otherwise it stayed cool. I also run purple ice, 22inch champion radiator.
 
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