Overheating problem

[DanJ]

Hello, I have a 69 dodge super bee with a 451 stroker, aluminum heads, sniper fuel system. I installed air conditioning. The car now wants to overheat, 195-200 degrees. I have new: water pump, 26" aluminum radiator, twin electric fans with shroud that covers the complete front of the radiator, radiator cap, radiator hoses. Was running 180 degree thermostrat, change to 160 no change. When I change to heat the temperature goes down some. There are no leaks and have fresh anti-freeze. Did not overheat prior to adding a/c. All suggestions are appreciated.

 

[Dennis H]

200 the high and stays there? AC doesn’t affect mine that way.

 

[Hemirunner]

That’s overheating? Hell, I used to run a 195 degree thermostat in mine. I bet if you ditched the electric fans and go to a 18” seven blade clutch fan, it’ll cool right down.

 

[R413]

195-200 is not overheating at all.

 

[snakeoil24]

Did you connect the sniper tooperate your secondary fan recognize that you need additional on time to accommodate the ac and also raise the idle speed on engine during ac operation? Also check the pump impeller back side is within .060 thousands from the pump body. Use silly putty and make an impression in pump cavity if the blades are too far then it will run hotter.

 

[davek]

did you do a 50/50 mix on antifreeze? Also you not over heating. is it 195/200 while driving or sitting?

 

[Dan64]

If you can post a picture of your fans, radiator. Also it never hurts to make sure your timing is set correct.

 

[RJRENTON]

Hello, I have a 69 dodge super bee with a 451 stroker, aluminum heads, sniper fuel system. I installed air conditioning. The car now wants to overheat, 195-200 degrees. I have new: water pump, 26" aluminum radiator, twin electric fans with shroud that covers the complete front of the radiator, radiator cap, radiator hoses. Was running 180 degree thermostrat, change to 160 no change. When I change to heat the temperature goes down some. There are no leaks and have fresh anti-freeze. Did not overheat prior to adding a/c. All suggestions are appreciated.

The surface area of the A/C condenser core is blocking the air flow to the vehicle's radiator snd in addition is adding to the heat load. Its like trying to cool 190°F. -200°F radiator coolant with 140°F - 150°F air coming from the A/C condenser.....there is not sufficient temperature differential in the combined air flow for effective heat transfer to keep the engine coolant temperature low. BTW, 190° F - 200° F coolant temperature IS NOT TOO HOT. Who made the determination that 180° F -190° F is the not to exceed number?
BOB RENTON

 

[Demonic]

What is the diameter of the opening of your thermostat? FWIW - the EMP/Stewart thermostats have an 1 7/16" opening, all the regular Stant thermostats are 1 1/8". Flow increases dramatically as the diamter is increased. As Bob and others said above, 200 is not overheating. If adding A/C made a big change, your rad could be near it's capacity to shed heat.

https://www.summitracing.com/parts/emp-301

 

[Thrashingcows]

The electric fans with shrouds are probably restricting air flow across the front of the condenser/rad...switch to a 7 blade clutch fan with shroud and I bet you'd have better cooling.

 

[Ron H]

Is your engine beyond the break-in period? More heat during the break-in. Had a hell of a time getting my motor running cooler; but this was appreciably higher temps than what you describe. I had read that some shrouds can impede cooling. Quite a science with desired air-flow. I found an OEM shroud and replaced the 4-blade fan with a 7. Among other things, I found anti-freeze ratios can impact cooling…a lower ratio of coolant is a better friend with cooling. Since I don’t drive my car in cold weather and sits in a heated garage, I reduced the mix to around 70-30%. Added a product “Water-Wetter” though there’s some household products I was informed about that can do the same as this product does cheaper. As well, in my hunt to drop the temp, is oil viscosity. I had been running racing oil 20-50 (hi-zinc with my solid lifters). Higher viz oils can retain engine heat from some oil expert’s articles, saying think more on what the necessity is for hi-viz oils. Will qualify I don’t have a motor near what you have; but mine lost some iron with boring out. Researching this, I found my oil pressure always very high, so switched to a lower viz racing oil. There’s more science here with recommended oil viscosity depending on the build. But, heavier weight oils aren’t always the best. Anyway, reduced my temp a good 15-degrees.

 

[Don67Satellite]

When I change to heat the temperature goes down some.

Make sure you have burped the cooling system completely and you have no air pockets left.

 

[68 Sport Satellite]

Lots to consider here as you're reading. Curious on what water pump you've got? On my mild 451 I had installed a 6-blade milodon, thinking that less blades is better for slower moving coolant. That was fine and I usually run 185-190F until I got stuck in a 30 min traffic jam where my coolant temp crept up to 230F. I've since come to the realization that faster moving coolant is better so I bought a Flow Kooler pump. I have yet to install it but have read good things.

 

[DanJ]

If you can post a picture of your fans, radiator. Also it never hurts to make sure your timing is set correct.

Here are pictures of radiator, a/c and fans.

 

[DanJ]

Make sure you have burped the cooling system completely and you have no air pockets left.

I'll burp system tomorrow. Thanks

 

[DanJ]

Is your engine beyond the break-in period? More heat during the break-in. Had a hell of a time getting my motor running cooler; but this was appreciably higher temps than what you describe. I had read that some shrouds can impede cooling. Quite a science with desired air-flow. I found an OEM shroud and replaced the 4-blade fan with a 7. Among other things, I found anti-freeze ratios can impact cooling…a lower ratio of coolant is a better friend with cooling. Since I don’t drive my car in cold weather and sits in a heated garage, I reduced the mix to around 70-30%. Added a product “Water-Wetter” though there’s some household products I was informed about that can do the same as this product does cheaper. As well, in my hunt to drop the temp, is oil viscosity. I had been running racing oil 20-50 (hi-zinc with my solid lifters). Higher viz oils can retain engine heat from some oil expert’s articles, saying think more on what the necessity is for hi-viz oils. Will qualify I don’t have a motor near what you have; but mine lost some iron with boring out. Researching this, I found my oil pressure always very high, so switched to a lower viz racing oil. There’s more science here with recommended oil viscosity depending on the build. But, heavier weight oils aren’t always the best. Anyway, reduced my temp a good 15-degrees.

Was running 20-50 Brad Penn not using 10-40 oil.

 

[DanJ]

./Thanks to all for the suggestions. I'll try them on Tuesday. I'll let you all know what happens. Thanks very much

 

[DanJ]

One of my biggest concerns with overheating is damaging the aluminum heads.

 

[Dan64]

Can't tell them the pictures but are the fans mounted directly to the radiator or to a shroud coving the whole back of the radiator? If so, is there holes with rubber covers cut into the shroud to allow air to go through at highway speeds, if not the air flow can dead-head and the shroud could work against you. If your shroud doesn't have the cut-out it would be easy enough to modify. Looks like a mechanical fan is a no- go due to the Wraptor serpentine set ( nice,btw). The Wraptor set up comes with a good pump so i would doubt that is the problem. The shroud cut-outs only come into play if it's getting hot while at speed.

 

[Hemirunner]

Good point, Dan. One thing I’ve learned over the years is that most electric fans block more air than a mechanical at highway speed and most actually move about half the air they’re rated for. Also, check voltage at the fan and make sure the electrical circuits supplying them will carry the amperage needed to run them. I run the same serpentine setup you do and made sure to include a mechanical clutch fan just to avoid the headaches of electric fans.