Don't be fooled by aftermarket cooling systems

[khryslerkid]

Where did you get the fan shroud? I don't see it in the links.

There isn't any link for the shroud. I measured what I needed, drew it up and had a local fab shop make it for me. (See the picture of the drawing) If I would have still worked in a fab shop, I could have made it myself.

 

[khryslerkid]

Wow... just realized I responded to a 6 year old post .

Hey, sometimes it's a good thing to start a thread up again. Things do change over the years with new ideas, new products. Also there might be some old tricks that have gotten lost over the years that work.

 

[Geri]

PLEASE MAKE THIS A STICKY.

I have posted most of this previously and thought it was a sticky but can’t find it so here goes again.

We see so many posts with people having cooling problems that have added aftermarket radiators and electric fans thinking they are improving things.

Don’t try to reinvent the wheel.

The standard H.D. factory cooling system should be fine for cars with 600 h.p. This system consists of 26” radiator with fan shroud and clutch fan. The clutch fan disengages when not needed saving the power robbing of the fan and basically free wheels.

Make sure your fan is placed properly about 1” inside the fan shroud. Some of the original cooling systems have some rubber or foam sealing around any air gaps around the shroud and radiator, if yours doesn’t it is a good idea to do so. Simple closed cell foam tape will work. This system was created by factory engineers and WORKS. Why? Because the shroud encompasses the entire back side of the radiator cooling area and creates a vortex with the fan in its proper place sucking the hot air off of the radiator from all surfaces of the radiator. Electric cooling fans are their own obstruction in this path of air. Don’t be confused by the fact that newer cars have electric cooling fans and work. Again that is a factory engineered system for a specific vehicle.

Another common mistake is using an aftermarket “high performance” water pump. The factory standard pump is usually fine and at the most you may want to use the factory pump that was designed for an A/C equipped car. If memory serves me correctly I believe that pump actually moves the coolant through the system SLOWER. Why? Because it has more time for the radiator to pull the heat out of the hot water. Most of the “high performance” water pumps move the water through the radiator too fast and does not give it enough time to remove the heat.

Thermostats are another problem. Some people that don’t understand their purpose will use a 160 degree unit thinking it will make the car run cooler. The 160 degree opens at that temp. but that doesn’t mean it is going to keep the temp. there. The factory suggested T-stat for our old cars is a 195. That is because your engine is designed to operate more effciently at that temp. On newer cars it is a 205 because of pollution control and a hotter engine burns more hydrocarbon than a cooler engine.

Timing is another issue for cooling. Especially with todays poor fuel. If you are running too much advance and your engine is predetonating (pinging that is not always autible) it will create addtional heat in the cumbustion chamber and may also cause you to burn valves or a hole in the pistons. This addition heat makes your cooling system work harder and may not suffeciently cool the engine. It can also cause starter bind (hard or slow staring wnen the engine is hot. This is caused by the starter expanding from the heat and being too tight. If your car was factory equipped with a heat sheild make sure you use one. If you have added headers and one or more of the tubes are close to the starter wrap those tubes with some type of fire retardant insulation material. DO NOT wrap the starter as it will eventually absorb the heat and then hold it there.

Good post and information the high performance Mopar water pump is the one with 6 blades not 8, that moves the water slower.

 

[bigmanjbmopar]

I find that the factory set will not work on storker motors this post is good for stock cars but once mods are made adjustments to everything else need to be made including the cooling system. Finding what works for your set up is the hardest thing and most costly.

 

[RJRENTON]

Gentlemen,
As I mentioned in previous discussions, VELOCITY is a key component of the cooling system, including the SPECIFIC HEAT CHARACTERISTICS OF the cooling medium.
A good velocity (circulation) is 15-20 ft/second which entails the use of the 8 blade mopar pump or a shrouded inlet pump such as Flow Cooler design. Try to determine the GALLONS/MINUTE of the pump, the more the better.
SPECIFIC HEAT refers to the coolant's ability to absorb (in the engine) and release heat (in the radiator) the heat collected.
Also the CHEMISTRY of the coolant (ethylene glycol, propylene glycol, water, and a water wetter [a surfactant]), and the system's operating pressure also influences the efficiency of the cooling system. Also remember that the FINS in the radiator (not the number of tubes) are the heat exchanger surface and should be maximized. Ideally, the best material of construction and the methodology of construction is the one variable that the owner must choose. Just my opinion of course.
Bob Renton

 

[MWFan]

PLEASE MAKE THIS A STICKY.

I have posted most of this previously and thought it was a sticky but can’t find it so here goes again.

We see so many posts with people having cooling problems that have added aftermarket radiators and electric fans thinking they are improving things.

Don’t try to reinvent the wheel.

The standard H.D. factory cooling system should be fine for cars with 600 h.p. This system consists of 26” radiator with fan shroud and clutch fan. The clutch fan disengages when not needed saving the power robbing of the fan and basically free wheels.

Make sure your fan is placed properly about 1” inside the fan shroud. Some of the original cooling systems have some rubber or foam sealing around any air gaps around the shroud and radiator, if yours doesn’t it is a good idea to do so. Simple closed cell foam tape will work. This system was created by factory engineers and WORKS. Why? Because the shroud encompasses the entire back side of the radiator cooling area and creates a vortex with the fan in its proper place sucking the hot air off of the radiator from all surfaces of the radiator. Electric cooling fans are their own obstruction in this path of air. Don’t be confused by the fact that newer cars have electric cooling fans and work. Again that is a factory engineered system for a specific vehicle.

Another common mistake is using an aftermarket “high performance” water pump. The factory standard pump is usually fine and at the most you may want to use the factory pump that was designed for an A/C equipped car. If memory serves me correctly I believe that pump actually moves the coolant through the system SLOWER. Why? Because it has more time for the radiator to pull the heat out of the hot water. Most of the “high performance” water pumps move the water through the radiator too fast and does not give it enough time to remove the heat.

Thermostats are another problem. Some people that don’t understand their purpose will use a 160 degree unit thinking it will make the car run cooler. The 160 degree opens at that temp. but that doesn’t mean it is going to keep the temp. there. The factory suggested T-stat for our old cars is a 195. That is because your engine is designed to operate more effciently at that temp. On newer cars it is a 205 because of pollution control and a hotter engine burns more hydrocarbon than a cooler engine.

Timing is another issue for cooling. Especially with todays poor fuel. If you are running too much advance and your engine is predetonating (pinging that is not always autible) it will create addtional heat in the cumbustion chamber and may also cause you to burn valves or a hole in the pistons. This addition heat makes your cooling system work harder and may not suffeciently cool the engine. It can also cause starter bind (hard or slow staring wnen the engine is hot. This is caused by the starter expanding from the heat and being too tight. If your car was factory equipped with a heat sheild make sure you use one. If you have added headers and one or more of the tubes are close to the starter wrap those tubes with some type of fire retardant insulation material. DO NOT wrap the starter as it will eventually absorb the heat and then hold it there.

Thank you for posting this. I bought my 64 Polara about six weeks ago, the car has a 440 Magnum clone. It had a Flexolite "Black Magic" fan attached with no shroud. If I sat at a light in hot weather, or idled around at a cruise in it would overheat very quickly. This car has the original type 22 inch three row radiator, and I tried to avoid the overheating by wiring a manual switch to the electric fan and running every time I stopped. It could not keep the car cool. I had been asking myself why this was not an issue when the car was built at the factory. This thread told me the answer. I checked and was amazed that a fan shroud was actually available...but by the time I paid taxes and shipping it would be nearl $400. I have done a lot of fiberglass boat work, so I decided to make a fiberglass shroud. I bought some good firm foam insulation for the perimeter and sealed it real good. As soon as I started it, I put my hand in front of the radiator and I could feel the airflow all the way to the edges of the radiator. Now my temp guage does not go above the "N" in the word normal. This is a big block with the SMALL radiator. The only non stock part is a stainless flex fan.
Anybody want to buy a used Flexolite Black Magic electric fan?

Thx, Bernie

 

[moperformance]

PLEASE MAKE THIS A STICKY.

I have one more addition to this and it's that a lot of people don't realize that the top radiator tank is actually an expansion tank.
Pre over flow tank days.
When filled properly (I use the second knuckle on my index finger from top of cap flange). The water has room to expand and contract under pressure. If it's filled to the top there's no where to go but out.

 

[Gunner1]

This is an excellent read.

 

[Robertop]

This is an excellent read.

Just my 2 cents, guys: I drove my 69 Hemi bird for 10 years back in the 1970's and never had an overhearing issue. Now, about other problems, I am keeping my mouth shut!

 

[Robertop]

Just my 2 cents, guys: I drove my 69 Hemi bird for 10 years back in the 1970's and never had an overhearing issue. Now, about other problems, I am keeping my mouth shut!

Oops, I meant overheating, obviously..