Fixing a Mustang's Overheating with a Maradyne Electric-Fan Swap

Cruise nights can draw a swarm of hot rods, muscle cars and high-horsepower late-model rides. As the crowd gathers, cruising speeds plunge to a crawl. If rubber-necking civilians become involved then a meltdown fest can happen. Slow cruising can be hard on a performance vehicle’s cooling system, because speeds slow down, less air flows into the radiator. This leaves you with only two options: pull over or find a way out. Thankfully Maradyne High Performance Fans has another option.

Hot Summer Nights

The owner of this ’65 Mustang Fastback was suffering overheating issues during cruise nights. Some of the problems were self-inflicted because of earlier changes to the cooling system. However, the only times it really became an issue was getting in a slow-moving lane. We typically saw it happen during crowded boulevard cruises on hot summer nights. While the Mustang has an engine temperature gauge, it reads cold-hot. We often saw it pegged to “H,” which as you may know is not an exact unit of measurement. To say our concerns were amplified was an understatement.

Here’s the situation that calls for a cooling upgrade. The original radiator had been replaced with an aftermarket aluminum model about seven years prior. However, the original shroud did not fit, leaving a lot of space that the factory 4-blade fan can’t affect.

The engine is a modified 289 K-code V8 that pulled 350 horsepower on the dyno. This setup can generate some heat in the iron block and heads. The original radiator was swapped for an aftermarket aluminum model years ago. The problem was that the factory shroud didn’t fit. This meant the original four-blade, crank-driven fan was left to do all the work. We saw installing an electric fan as a positive move to improve the weak cooling system. In addition, the fan draws more air than the factory unit and covers a large area of the radiator.

Maradyne Time

Maradyne’s 16-inch, 225-watt reversible fan seemed like the perfect solution. The 10-blade unit is constructed of glass-filled nylon and features a sealed motor design. At 7-pounds, it doesn’t weigh much more than the steel fan it’s replacing. Finally, the low-profile design provides more than enough clearance for an easy install.

We spoke with Jim Kahl from Maradyne about its 16-inch fan.

“Part number MC162K is the flagship fan of the Champion line. The IP68-rated sealed motor can handle dirt, dust and is even water resistant to 5-meters. At only 3.19-inches deep it can fit into cramped engine spaces while providing 2170 CFM with only an 18-amp draw.”

All the parts were unpackaged and laid out on a table. Wiring diagrams and instructions come with the products.

The fan was ordered along with a wiring harness with thermostat and an aluminum bracket kit. Helping with the installation was Don Holcomb at Whipple Racing Products in Rapid City, South Dakota.

Installing the Hard Parts

The first chore was removing the stock fan and touching up the paint on the water pump pulley. After the pulley was bolted in place, the fan could be mocked up to check for clearances and evaluate the mounting strategy. The Maradyne fan blade was also checked to ensure it was in the puller position and not set up to push air through the radiator.

The first step was removing the fan and spacer from the pulley. The pulley was touched up with Satin Black paint to match the engine, and it then bolted back on to the water pump with shorter 5/16-inch bolts.

The Maradyne fan was test-fitted against the radiator to check for clearance and coverage.

The aftermarket radiator already had integrated mounting flanges with a few pre-drilled holes, but the plastic mounting brackets supplied with the fan were too short to reach those holes. Holcomb mocked up the universal mounting brackets, but they wouldn’t allow the fan to lay flush on the radiator.

The universal bracket was mocked up but there were too many issues with alignment.

Fortunately, the speed shop had a set of universal fan mounts that were long enough to reach the integrated flanges on the radiator. A couple of holes needed to be elongated and two more were drilled to match the footprint of the plastic mounts after they were installed on the fan. All that was needed were four bolts and nuts to secure the fan to the radiator.

Whipple Racing had fan mounting clips in stock that were much longer than those provided with the universal brackets. They were test-fitted against the existing radiator bracket while loosely positioned before being hammered into place on the fan housing.

Holes were drilled or elongated in the existing radiator bracket, then the brackets were trimmed and rounded off for a clean appearance.

The fan was easily bolted in place using ¼-inch bolts and nuts.

Getting Wired!

Installing the wiring harness was rather simple since the Mustang didn’t have air-conditioning, nor were multiple fans involved. The kit includes an adjustable thermostat with a remote sensing bulb. The thermostat can be adjusted to engage the fan from 32 to 248 degrees Fahrenheit. The remote bulb should be inserted between the fins close to the water tank on the inlet side. The bulb tip should not be exposed to an area of high airflow to reduce the chances of a false reading. Holcomb took the added precaution of installing a rubber vacuum plug over the bulb so that incoming air would not affect the readings.

A few basic butt connections were required to mate the harness with the leads from the fan and to stretch a line under the dash for a key-on power lead. All the butt connections were made with the proper heat-shrink connectors. The key-on power source was found at the fuse panel.

The wiring harness was laid place in front of the radiator, and the thermostat was mounted in a convenient place on the core support. The remote sensing bulb is inserted through the radiator fins just under the tank. A small rubber vacuum plug was placed over the tip of the bulb to keep incoming air from affecting the sensor signal.

Wiring diagrams cover a variety of vehicle equipment scenarios, but the Mustang was easy because it didn’t have A/C or multiple fans. All connections were insulated when required and the wiring was tucked and secured as needed.

A few months prior to this install, the Mustang had a replacement under-dash wiring harness installed. This upgraded model included a modern fuse block with extra terminals. A probe light was used to find a spare key-on terminal.

Holcomb used 14-guage wire for the lead from the fuse block to the wiring harness. Once the system was tested, the wiring harness was double checked for connections, and plenty of zip ties were used to ensure the wire routing was clean and out of the way.

The Mustang didn’t have an analog temp gauge, so an infrared thermometer was used to set the thermostat to start the fan at around 175 degrees.

Final Thoughts

So far, the system works perfectly. There have been no temperature spikes during slow traffic. The fan is rated with a power draw of 18 amps, but that hasn’t affected any other electrical operations. Overall, it took about three hours to install the fan and wiring harness with basic hand tools, a drill, and an electrical power probe…not a bad way to spend a few hours in the garage!