A lot of time seems to be spent discussing the merits of one particular cooling system feature versus another. Brass/copper radiator versus aluminum. Electric fan versus mechanical. Three-row? Four-row? Dual pass? Thermostat or no? What psi radiator cap? There is a lot to digest, but once it’s said and done, it seems the cooling system is a wrap. But there’s more to reducing the temps of an engine, and, more specifically, the powertrain as a whole, than just the cooling system and its related components.
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To handle cooling the engine’s oil, Derale recommended their Series 9000 plate and fin cooler (PN 33603). This 13-row furnace-brazed aluminum cooler features 1 1/4-inch-wide plates and embossed turbulators designed to maximize heat transfer and minimize pressure drop.
Knee deep in the LS swap on our buddy Bruce Valley’s ’57 Chevy wagon, we had decided not to route the transmission fluid through the radiator. Keeping a hard-working V-8 cool is difficult enough, add to it hot transmission fluid and that poor radiator would be doing all it could to keep up. Instead, we opted to add an external cooler to handle the transmission fluid duties and contacted the guys at Derale Performance to walk us through what we needed to know. After a short phone conversation, we ended up with a longer list of components than we originally intended, due to the education we received from the Derale team.
Keeping the transmission fluid cool will be the responsibility of Derale’s Hyper-Cool Dual Cool Remote Cooler (PN 15845).
Originally, engine oil cooling wasn’t given much of a thought and transmission cooling an afterthought, being routed through the radiator where the fluid’s heat was absorbed by the engine coolant (which itself was trying to cool at the same time!). For the most part, this system proved effective, at least until power output increased to a level where it no longer did. Today, it’s understood that nearly all late-model powerplants and anything else making decent power can only benefit from the addition of external coolers.
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This 19-row stack plate cooler features two 5-inch electric fans to supply optimum airflow, allowing for installation in nearly any location. It also features an integrated aluminum fan shroud that doubles as a mounting bracket, making installation a breeze.
When it comes to the engine oiling system, we’re typically only concerned with one thing: pressure. Keep the oil clean and watch the pressure and all’s well, right? Well, it just so happens that keeping that engine oil cool also helps the cooling system do its job and increases its efficiency. By absorbing the engine oil’s heat and exchanging it with ambient air, an aluminum plate-and-fin oil cooler helps keep the oil from breaking down and increases its ability to do its job, lubricating the internal components and helping keep internal temps down at the same time.
Choosing the ideal location for an external cooler is typically a function of convenience and airflow. Since our transmission cooler features a pair of electric fans to provide its own airflow, we’ll only be concerned with convenience for its location. That said, we picked a location under the passenger side floorplan, where the cooler is protected by the framerail and located on the same side as the transmission fluid outlets.
That same theory works just as well to keep the fluid of an automatic transmission in check and within the range of optimum operation. This is imperative when it comes to the street performance aspect of many of our classic Chevys where that transmission is responsible for transmitting massive amounts of torque and horsepower to the rear wheels of a fairly heavy vintage sedan. Managing all that power can generate some serious heat, and heat is the enemy of the automatic transmission. Too much and things go bad in a hurry. So, the responsibilities of the transmission cooler are of utmost importance.
While the engine oil cooler does not feature built-in fans, airflow isn’t as imperative as the trans cooler since its only function is to provide supplemental cooling to the engine, not primary cooling. We opted to install the engine oil cooler in the same location, on the opposite side of the car.
Heeding Derale’s advice, we opted to use an external cooler for both the engine oil and the transmission fluid on our LS swap in addition to an electric fan controller, which we’ll cover in a future story. The addition of an external cooler is a fairly simple affair, consisting of choosing the proper location, installing the cooler, and routing the lines from the engine/trans to said cooler. But there are a few tips and tricks that we hope to be gleaned from our install, including the proper selection of hose, clamps, and fittings.
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Routing the engine oil out to the cooler and back into the engine block is achieved using a Derale LS Engine Oil Cooler Adapter (PN 35611), which replaces the stock block-off adapter located just above the oil filter. Note the adapter has been equipped with AN-8 male fittings.An alternative option, and one for the earlier generation small-block guys, is this Derale Sandwich Adapter (PN 15735) that allows the addition of oil cooler lines without relocating the stock spin-on-engine oil filter.Like the engine oil cooler, we’ll be using AN fittings on the trans cooler side as well. To do so, we’ll need to install a pair of Earl’s AN-6 transmission adapters from Summit Racing (PN 961982ERL). These adapt the GM 4L60E transmission fluid ports from 9/16-18 to AN-6 male.Running hoses underneath a vehicle can be a tricky task as we need to avoid anything sharp, hot, or that might negatively affect the hose in any way, shape, or form. That means they need to be mounted firmly and not be allowed to hang, bounce, or swing around under the car.We’ll be using a combination of Russell AN Hose Separators from Summit Racing (PN RUS-654313) to group the AN-8 hoses together and stainless steel Kugel Komponents line clamps (PN 6507) to secure the hoses to the transmission and sheetmetal underneath the body.Care is taken to ensure none of the lines or fittings foul any of the surrounding sheemetal after installation. Here, one of the engine oil lines passes closely between the frame and body, without touching either thanks to careful positioning and clamping.A pair of 45-degree AN-6 hose ends are used on the transmission side of the cooler lines.Like the engine cooler lines, the transmission cooler lines are held in place by another combination of Russell AN hose separators (PN RUS-654303) and Kugel Komponents line clamps (PN 6506), sized for the AN-6 hose that’s being used on the transmission side.Once again, care in the routing is of utmost concern.We don’t need the transmission cooler’s electric fans to run constantly, so we’ll be controlling them with a Derale In-Line Fan Control Thermostat kit (PN 35020), set to switch the fans on when the fluid entering the cooler from the transmission reaches 180 degrees.The guys at Derale recommended AN-8 size hose for the engine oil cooler and AN-6 for the transmission cooler. As mentioned in the text, we’ll be using Russell Twist-Lok hose purchased from Summit (PN RUS-634203 for AN-8 and PN RUS-634163 for AN-6).A variety of hose ends are available for the Twist-Lok–style hose, from straight to 45- to 90-degree, and we used at least one of each.The Koul Tools EZ-ON Hose Press tool really did save the day when it came to assembling this style hose, the ease of installation versus man-handling the darn things was worth the price of admission! Operation is simple, the fitting is secured in the far end vise, along with the corresponding tooling, spec’d to the specific hose diameter, and cinched tight. Next, the hose is placed against the barb on the fitting and the hose vise cinched tight as well. I used a few drops of oil to aid in assembly before slowly driving the hose onto the fitting using the drive screw. Unbelievably simple and amazingly functional.Here’s an example of an assembled AN-6 Twist-Lok assembly from our LS fuel system. The Twist-Lok line is a great alternative to other, more expensive AN systems out there, and the plain rubber hose blends in nicely in any engine compartment.
