Pontiac Cooling System Upgrade - Cool Winds

With winter starting to rear its ugly head in the colder regions of the country, the steamy days of the past summer may seem a distant memory, but not for those among you who suffered from cooling system maladies in your favorite classic Pontiac. Though it may seem counterintuitive to discuss engine cooling at this time of year, the truth of the matter is that most of you finally have the time to do something about your poor-performing cooling system since your Pontiac won't be showing or cruising for a while.

In Part I, we introduced you to a '66 Tempest owned by Floyd Hand of Dallas, Texas. It is a stellar performer and routinely runs mid 11-second quarter-mile e.t.'s, utilizing a 0.030 over 455 and Jim Hand-ported iron No. 7K3 cylinder heads. Its stock-type cooling system was ready for an upgrade, so we detailed the installation of its new components.

The decision to employ an aluminum Performance Rod and Custom (PRC) radiator, SPAL 16-inch electric fan and Meziere electric water pump and the required Butler Performance Alternator Relocation Kit was more geared toward improved dragstrip cooling, with street performance a close second. The Meziere electric pump-unlike the stock mechanical pump-can be run in the pits with the car shut off to cool the engine much more quickly between rounds. The fact that the pump is stated to work on the street as well was an added bonus that would allow the weekend racer, who likes to drive to the track, to have his cooling-system cake and eat it too, so to speak. Though we had little doubt that the modifications would show improvement at the track, the question was how would the electric pump and the remaining components fare around town and on the highway?

To that end, in Part II we will test the effectiveness of the upgraded cooling system in many situations and endeavor to maximize its efficiency.

The Testing Parameters
Testing of the '66 Tempest was performed utilizing a Raytek AutoPro Infrared thermometer and an aftermarket in-car mechanical coolant temperature gauge mounted in the intake manifold crossover. The infrared thermometer was pointed at the "pad" located above the spark plug on cylinder No. 1 (driver side front cylinder) and cylinder No. 6 (passenger side, third cylinder from front). After determining that the mechanical gauge matched the readings when the SPAL relay turned on and off (185 and 165 degrees respectively), the SPAL sensor was moved to the No. 6 cylinder.

Four different conditions were tested. The first was "low-speed" cruising, which amounted to driving the car at speeds that were between 25 and 40 mph for two miles. The second condition was "high-speed" and was for all intents and purposes a hard quarter-mile pass, immediately following the recording of low-speed readings. The third series of tests was "highway," which consisted of driving the car between 55 and 68 mph for 10 miles on a rural interstate. The fourth series of tests was "extended highway"-a 50-mile round trip on an interstate highway driving between 65 and 70 mph. After completing each test, the Pontiac was pulled to the side of the road and left idling. A reading was taken from the in-car gauge and then the hood was popped open to take infrared thermometer readings.

The Baseline
The '66 utilized an OEM-style four-core brass and copper radiator with a shroud from a GTO. Equipped with a stock-type iron water pump, a seven-blade factory clutch fan and a 160-degree Stant SuperStat thermostat, the Pontiac didn't overheat-but it did routinely see over 200-degree coolant temps after being driven hard on the street, or at the end of the quarter-mile. When driven on the highway, the coolant temps steadily climbed to 210 degrees.