Bulletproof Checker Cooling System
One problem a lot of Checker owners have is keeping the engine cool. From looking under a lot of Checker hoods, I have decided this is caused by one of four problems: (1) no fan shroud, (2) 5 blade fan instead of heavy duty 7 blade fan, (3) two core radiator instead of three core radiator and (4) driving the car in excess of 70 MPH since I believe the (lack of) aerodynamics impede air flow through the radiator.
In years past I rebuilt the radiator using a new three-core center section with the original upper and lower tanks, installed a seven blade clutch fan and added a simple homemade box type fan shroud. These steps had been adequate at the time but when I recently swapped a fuel injected 4.3 V-6 in place of the original 3.8 V-6 I decided to upgrade my cooling system at the same time. I wanted a bulletproof solution that would keep the engine cool under the worst possible conditions.
My solution consisted of four steps: (1) removing the homemade shroud, (2) testing the radiator to make sure it still meet specifications and repainting it flat black, (3) installing a 18 inch stainless steel flex fan in place of the original equipment clutch fan and (4) adding a pair of 10 inch electric cooling fans mounted directly on the back of the radiator with a thermostatic control. Why did I do this and what was the result?
If the radiator is not in good condition, anything else you do will only be partly effective. Remove and inspect it. If it is not a 3-core unit, decide to rebuild or replace it. If it is a 3-core unit, take it to a shop specializing in radiator repair. Have the radiator boiled out, pressure tested and flow tested. Mine was pressure tested a couple of pounds higher than the cap I use just to be sure it was up to par. The shop will usually paint it flat black as part of the procedure. I added some more flat black get a good coat on and improve heat transfer. Don’t install the radiator until you have mounted the electric fans.
I installed an 18-inch stainless steel flex fan purchased at Auto Zone although most parts stores carry them. A 19-inch fan will fit (my factory fan was 19 inch) but I decided to have a bit extra clearance between the radiator hoses and the fan (and my fingers!). The flex fan has several advantages over the original factory clutch fan: (1) lighter weight so less stress on the water pump bearing, (2) no clutch assembly to fail, (3) robs less horsepower since the blades flatten out at higher RPM and (4) it looks SO much better under the hood. The flex fan has two major disadvantages: (1) it is sharp and easy to cut yourself on when working under the hood and (2) when flat at high RPM it doesn’t move as much air, instead depending on vehicle speed to force air through the radiator.
Note: Most fans are mounted to the water pump with a spacer for proper clearance between both the motor and the radiator. I used the factory 1 ½ inch spacer since it provided roughly 5 inches of space between the fan and the radiator. If you were only using the flex fan, you should try to find a spacer that will leave only 2 – 3 inches between the fan and the radiator. If you install a spacer different than the factory one, you will most likely need to buy new studs of the proper length. Use new nuts and lock washers, preferably stainless, and a drop of blue Locktite to make sure everything stays tight.
I then installed a pair of electric cooling fans just like you see on the new cars; you know, the ones that startle you by starting up after you’ve parked the car and are walking away. These fans come in various sizes and you could use just one but if it fails then you would have no extra cooling. By taking the radiator into the parts store and experimenting we determined that a pair of 10 fans would nicely fill the radiator area. Since these fans come preassembled with their own plastic shroud, I removed the homemade metal box shroud I had built. I also used an adjustable thermostatic control so I could choose when to have the fans come on. You will need a minimum of 2 ½ - 3 inches of clearance between the radiator and the fan mounted on the water pump in order to install the electric fans.
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