Steve Baur
Former Editor, Modified Mustangs & Fords
January 24, 2007
The Evans Cooling kit includes everything you need to keep your pony cool. The electric fan is available as an option. You can use your stock clutch fan, or ECS can supply you with either a single or dual-electric unit.

The ever-aging 5-liter Mustang suffers from many maladies, and one of the most important is cooling system degradation. Barely adequate for the stock engine, performance modifications can place a higher demand on an already taxed system. Add in the average age of the components and you have the perfect recipe for poor cooling.

Sit in any black Mustang GT that's idling in traffic during an average 95-degree summer day, and you can watch the temperature needle rise. AOD-equipped cars have it even worse because part of the radiator is used for transmission cooling.

The stock 5-liter cooling system also suffers from another problem. "Ford downsized the diameter of the radiator inlets on the Fox Mustang and this restricts the flow of the coolant and ultimately hurts the performance of the system," said Dave Wright of Evans Cooling Systems. "They actually went up a size when they went to the '94-95 models. Flow is everything when you're talking about performance applications."

Evan Cooling Systems (ECS) has advanced cooling components for all kinds of vehicles, including diesel trucks, race engines and street cars. The key component is its NPG coolant. NPG, which stands for non-aqueous propylene glycol, is a waterless coolant. Why is this important you ask? Well we're about to tell you.

We said goodbye to cracked clutch fans and cruddy radiators. This job is really simple if you have basic mechanical skills and tools. Heating the drain plugs will be the most difficult task, and if you don't feel comfortable with doing that or replacing the water pump, you might want to have a professional technician complete the job. We spent two days on the installation, but if you work straight through, it shouldn't take longer than four or five hours. We did ours in mid winter and the garage wasn't heated, so we took frequent breaks to let our hands thaw out.

The main thing to know about water is at a certain temperature, it turns to vapor. Water vapor doesn't absorb the heat from the metal surfaces that it is trying to cool (namely cylinder heads and walls), and this creates higher combustion temperatures, which can lead to detonation. Detonation is bad, very bad. Evans NPG and NPG+ coolants contain no water, so you never encounter a vapor-related overheating situation. They also have boiling points of 370 and 375 degrees respectively. This keeps the internal engine components cool and happy, even under higher than normal temperatures.

Water-based coolants use a higher system pressure in order to raise the boiling point of the coolant and while this is effective, it has its downside. Increased pressure means more strain on the individual components like hoses and gaskets. The high-boiling point of the NPG coolant allows it to run with little or no system pressure at all. At colder temperatures, water will freeze and expand, which is why engines are equipped with freeze-out plugs. Propylene glycol, on the other hand, shrinks and becomes a gel. NPG's waterless nature eliminates system corrosion and water pump cavitation, too.

NPG is ECS's original formula that was designed primarily for racing applications. NPG+ adds ethylene glycol to change the viscosity below 0 degrees Fahrenheit. Racers need to check with their local tracks, as some do not allow the use of ethylene-glycol coolants. If it's a strip only machine, chances are you're not worried about sub-zero performance anyway. The fact that the NPG coolant doesn't evaporate means you never have to add to it, and ECS claims their test vehicles with over 200,00 miles on them show no signs of chemical deterioration, which makes the system virtually maintenance free.

In addition to the NPG coolant, ECS also has complete cooling systems for vehicle-specific applications. These systems include a custom high-flow/high-capacity aluminum radiator, redesigned or modified water pump, ECS-specific thermostat, hoses and special clamps. Cooling fans are an option, as the user can choose between their factory unit or the high-performance pieces ECS sells.

We recently bolted on a ProCharger P-1SC supercharger to our resident '90 Mustang GT. While the intercooled ProCharger generates lower intake temperatures than a normal centrifugal unit, we felt the coolant system should be upgraded not only for improved performance, but to protect the engine under boost conditions. Long time MM&FF readers may recall project Code Blue, our Vortech-blown '93 GT. We had quite a few issues with managing heat in the engine after the supercharger install and we were going to make sure this didn't happen again with our latest project.

Our stock cooling system has seen a couple of water pump replacements, a new radiator and even a 180-degree thermostat, but water temperatures have no fear of heights come summertime, even with the naturally aspirated stock powerplant. Since the supercharged combination has yet to see summer duty, we're going the preventative maintenance route by installing a high-performance cooling system before those problems have a chance to make themselves known. This will also be helpful as we intend to increase the boost level later on.

Installation is fairly straight forward, and a lot easier if you have replaced the water pump before. Some very minor fabrication was needed for the radiator support brackets and when mounting the coolant reservoir, but it wasn't anything difficult.

After the system has been drained, remove the upper and lower radiator hoses and then take off the radiator support brackets. The radiator is now free so pull it out of the car, being careful not to leak any coolant onto the vehicle. Now you're ready to remove the water pump studs. They are of various lengths, so be sure to mark them so you know which one goes where during reassembly. You can take out the two bolts that secure the thermostat housing, and then remove the heater supply hose from the heater line on the lower intake manifold. At this point, take off the heater bypass hose, which runs from the thermostat housing to the water pump. You can also leave it on and remove all of the pieces together.

Evans recommends removing the drain plugs in order to eliminate all of the old coolant from the system. The drain plugs gave us quite the fight and refused to come out. You'll probably need to heat them up with a welder. A small propane torch might work, but we didn't try one.

The final coolant mixture should have no more than five percent of water content, so removing the drain plugs is essential. If you can't get them out, you can send ECS a 1-ounce sample of the coolant from the radiator in a screw-on type container, and they can tell you what the mixture is. They also have test strips that you can get to make sure you're in the ballpark. If you need to do this, call their phone number listed below, as there is a different address to send the sample to.

The ECS system for the 5-liter Mustang sells for $895, and features a high-flow aluminum radiator (made for ECS by Griffin), a high-flow water pump, thermostat housing and thermostat, gaskets, hoses, clamps and, of course, 5 gallons of NPG+. ECS also offers a variety of overflow tanks as well as electric fans for any application. We opted to replace the stock clutch fan and went with a single electric unit ($129.99), as our supercharger did not offer the necessary room to fit the dual setup ($249.99). For those living in warmer climates, or cars with custom computer tuning, ECS recommends they not use the included thermostat, as the system is designed to flow openly. People in the colder northern climates may want to use it to get some heat from the engine.

Our detailed captions will get you through the installation of the Evans Cooling Systems kit. The ECS kit comes with detailed instructions, and its Website is quite helpful should you have other questions. A Chiltons or Haynes manual will come in handy if this is the first time you have replaced the water pump.

Whether your car is unnaturally aspirated or not, it can benefit from a high-performance cooling system. The factory design is good at best and as our cars get older, most of these parts will need to be replaced anyway, so it only makes sense to upgrade. After all, that's what you're doing to the rest of the engine. Ignoring your cooling system is like ignoring your brakes. You're only asking for trouble, so read on to find out how to make your cooling system perform like a pro.

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