Air pocket maybe
have a 69 gtx with a 440, have a small over heating issue, i will drive the car for about 45 mins and and it will fluctuate between 180 and 190, then over then next ten mins it will hit close to 230
, i change thermostat gasket flushed antifreeze and still didnt fix the problem, have no leaks or anything kinda stumps, me if any1 has any insight please fill me in
Is the block bore to 0.060" over ??, Is the water pump any good ??, is there any obstruction in the block ??, Is the radiator any good ??, Is you ignition timing correct ??, retarded ignition will cause over heating also... is the carburetor tuned properly & not too lean ??... Have you flushed the
whole cooling system thoroughly ??, not just the radiator... Is the fan working properly ??, do you have the original "clutch fan" still ??, do you still have a fan shroud ?? you should... how close is the fan to the radiator ??, it should be around 1" or even closer, depending on the style of blades & materials on the fan... Is it a steel fan or an aluminum fan ??, is the car equipped with a 22" or 26" radiator ??, what size radiator did the car come with ??, a car originally equipped with a 22" rad. will have a smaller opening in the radiator support, than a car originally equipped with a 26" rad., it could restrict the air flow... As you can see there lots of variable here... Maybe just add an auxiliary electric fan on a thermal switch, that comes on when the temperature goes over 200*, if you do use a relay for the wiring & an override switch... Also high performance engines can run hot, especially with higher compression, large camshafts, headers, under-hood heat, etc... You can remove the thermostat & put just a large thin fender washer same diameter as the thermostat, with a 5/8" hole in the center, in place of the thermostat, it will still have enough restriction, to keep water in the radiator long enough to cool it, before going back into the engine, many times works better, especially in warmer weather, not so good in cold weather... I once had a 440 block with a bunch of freeze plug stuck between cylinders kind of, someone drove them in, instead of removing them, it was a total bitch & got hot, until I finally found it... If you don't think it's the gauge reading wrong, you may want to try this... It may have an air pocket or something, did you open your heater controller wide open, to let water pass thru & fill the heater core, then top it off again, then with the thermostat open at running temperature, with the radiator cap off, squeeze the top & bottom radiator hoses a couple of times see if you get a bunch of bubbling... If all else fails... Moroso makes an 1/8th male/NPT "push to activate"
air bleed, they are cheap & easy to install, made for water, cooling & fuel systems, you can put in the top of the water pump housing, in an 1/8 NPT port or at any place you can put a fitting in a hose {
at the highest point preferably}, with an 1/8th NPT female hole, you can relieve all air in the system, with the cap on & pressurized, then refill/top off again, especially if you have an aftermarket aluminum housing with 2 different temperature sending unit ports, it works very well there, it's a trick from my old winged sprint car days/on SBC's, always seemed to have trouble getting all the air out of the system, but it works on Mopars too... You could try a slightly higher pressure on the radiator cap, like 18psi {
maybe 20psi even, if the radiator & hoses are all in great shape}, instead of 16psi, the boiling point is 10*-15* degrees or so higher under every 2 or so pounds/psi higher pressures over 13psi-15psi range... Just some thing to think about... sorry for my analness...LOL..
