If there's one problem that's always haunted us, it's overheating. Heat is the number one killer of just about every drivetrain component there is. And we've managed to overheat just about every drivetrain part there is. Our last little cooling incident was due to an excessive right foot in a freeway race, which caused the engine to overheat, which lead to a head gasket blowing, which wasted the radiator, which melted the plastic transmission lines (yes, of course our '94 Dodge was the only model year to receive these plastic beauties) because they ran into the radiator for heat exchanging in cold climates. The melted tranny lines bled all the tranny fluid out, which in turn burned up the tranny's bearings and torque converter.
That wasn't the first time cooling troubles had dominoed for us, and we're sure it won't be the last. On the bright side, all our cooling calamities have made us learn some pretty cool tricks to keep our trucks...well, cool. So we're passing on what we can in hopes that you might not be hitching a ride home like we've had to do more times than we care to count.
On almost every auto tranny vehicle, the tranny's cooling lines are run into the radiator. This is done for two reasons. First, to cool the transmission. Second is so the radiator quickly warms up the tranny fluid in cold climates to allow proper functioning of the transmission. This is a necessary evil for guys living in cold climates, but for warm-weathered folk, it's really not necessary to run the tranny cooling lines into the radiator because it doesn't (usually) get cold enough to thicken up the tranny fluid to the point of ill operation. After our last little engine and tranny debacle, we decided it'd be a good idea to totally separate the tranny cooling system and the engine cooling system. We simply capped off the lines to the radiator, and ran the tranny lines to a B&M (www.bmracing.com) auxiliary tranny cooler with an attached electric fan. This way, if we ever roast the coolant in the engine, we won't be adding another $3,000 to our repair bill for a new tranny.
One of the easiest types of preventive maintenance for your cooling system is to make sure to replace your radiator cap and thermostat every 20,000 miles or every couple of years if not driven that much. Thermostats stay in a closed position, allowing very little waterflow through until the engine heats up to a certain temperature. If the thermostat gets sticky, then it might not fully open up which in turn will not allow enough coolant to run through the system. The radiator cap usually holds either 13 or 16 pounds of pressure within your cooling system. If the cap is old or faulty, proper pressure will not be held and your cooling system could boil and overflow, emptying your cooling system of its vitals. | 
Header wrap like this stuff from Thermotec (800.274.8437, www.thermotec.com) is a great way to keep as much exhaust heat as possible flowing out the tailpipe instead of leaching into your engine compartment. The header wrap makes a good barrier, keeping the headers from radiating heat that might prematurely weaken your battery, alternator, electronic ignition, or any other component under the hood that would be better off at room temperature. | 
A nice and easy way to make sure you have the proper 50/50 balance of coolant and water is to buy premixed coolant instead of trying to guess how much fluid your radiator takes and pouring in too much of one or the other. If you're replacing all the fluid in your cooling system and don't use 50/50 coolant, then use distilled water if you can. It does not have ions in it that will rust the interior of your radiator like tap water will. |
You've probably seen a lot of trucks running around with aftermarket grilles lately. Be aware! We've seen some pretty scary stuff out there that looks like it blocks more than 50 percent of the airflow into the radiator. Not enough airflow, and your cooling system will be gasping for a way to release the heat from the radiator's fins. If you do bolt on an aftermarket grille, make sure there are plenty of air passages. | 
Auxiliary coolers can be bought at almost any auto parts store across America and are almost certainly never a bad thing to add to your vehicle. Auxiliary coolers can be used to cool steering systems, engine oil, tranny fluid, or even differential fluid if you want to get really high-tech and run a pump to your axlehousing. We cannot think of one instance where you wouldn't benefit from an auxiliary cooler (unless you place it in a position where it could get whacked by something). | 
Silicone hoses are a great way to ensure that you'll almost never have a blown hose. Silicone hoses from BRX Products (951.662.2009, www.brxproducts.com) give you more insurance for your cooling system for not too much more money. On top of that, these come with a lifetime warranty and a burst pressure above 350 psig. It's hard to beat that. |
We like preventive maintenance (when we think about it). One upgrade we made to our '75 Dodge was to replace the original 30-year-old radiator with a drop-in replacement unit we bought from Radiators.com. The unit did a great job of lowering our temperature over the original clogged one, and many times you can order more cooling rows than the factory offered. | 
High-flow water pumps do a better job of pushing water/coolant through your cooling system without having to spin the pump faster. This unit from Flowkooler (805.544.8841, www.flowkooler.com) bolts directly in place of the OEM unit and comes with a special impeller that creates up to 15 percent more water flow. | 
Heat rises, and a great way to let it keep rising is to place some hood vents above the engine. These units from Race Ace (www.raceace.com) took about 45 minutes to install and let out a lot of built-up heat. We know they work well too, since most of our hood is now cool to the touch, while those hood vents are piping hot. |
Differentials need to cool off too. We put bigger tires on trucks, haul huge loads, and on top of that, do it with speed. Those poor rear ends are just burning up inside since we're not increasing their cooling capacity when we make all these mods. One great way to keep your rear axle cooler is to use a larger capacity differential cover like this one from Mag-Hytec (818.786.8325, www.mag-hytec.com). Not only does it allow more fluid to be held, it also has a finned aluminum housing that acts as a heat sink, dissipating a considerable amount of heat over your stock differential cover. | 
Heat doesn't just kill drivetrain components. It can melt important sensors or wires as well. When you have to run important lines near exhaust manifolds or pipes, it's a great idea to use some heat-resistant wire insulation like this stuff from DEI (800.264.9472, www. designengineering.com) to keep your integral wires and lines from scorching or burning through. | |