Virtually every vehicle produced comes with its own unique list of quirks, weak links, or catastrophic failure points. Sometimes even when a “new-and-improved” successor model solves prior issues, it brings with it a new breed of problems. Case in point, while the 6.4L Power Stroke’s revised head bolt and EGR system ruled out a lot of the blown head gasket issues associated with its predecessor, the infamous 6.0L, the compound turbo’d diesel mill in ’08-’10 Super Dutys quickly became notorious for something else: leaking radiators. Be it from chassis flex or poor build quality (there are theories which support both), failed radiators run rampant in these trucks. If you own a 6.4L Power Stroke and haven’t had to replace the radiator, consider yourself lucky. Nearly nine out of every 10 don’t make it past 100,000 miles.
With a reputation for offering products that solve both large scale and pesky, common problems on diesel trucks, Mishimoto Automotive designed an all-aluminum replacement radiator for the 6.4L engine. Not only are the end tanks TIG-welded to the core (instead of plastic units crimped onto an aluminum core), but the rubber-fitted mounting pegs relieve the stress that’s placed on the end tanks themselves. Throw in its added coolant capacity, stronger top and bottom core support plates and OEM-style, quick-disconnect connection points, and you’ve got a direct, drop-in radiator that solves a multitude of issues and provides long-term durability. It’s the cure for one of the 6.4L’s most common problems—and they sell like hot cakes.
We recently installed one of Mishimoto’s aluminum radiators on a ’10 F-250, a process that took roughly three hours. Follow along as we pinpoint the spot where the factory radiators fail and prove why the Mishimoto radiator outperforms and outlasts the factory piece.
Out With the Old
Pulling the radiator on an ’08-’10 6.4L Power Stroke is very straightforward, but it is a bit involved. It calls for the removal of both the intercooler and the upper radiator support, along with disconnecting the transmission cooler bolts, transmission cooler lines and A/C condenser from the radiator. No special tools are required, but rather a small assortment of sockets (8mm, 10mm, 11mm deep well socket and 13mm), a ratchet, ratchet extension, needle nose pliers and a flathead screwdriver. Of course, you’ll want to take care to drain the coolant into a clean pan (if you plan to reuse it) or start over with fresh coolant. We recommend Motorcraft Premium Gold Engine Coolant if you choose the latter.
Bursting at the Seams
This is the fate of most factory 6.4L intercoolers: the plastic end tanks separating from the aluminum core they’re crimped onto. If you notice coolant pooling under the front of the truck, it always pays to check to see if the lower radiator hose is the culprit, as they’re prone to leaking almost as often as the radiators themselves. The upper mounting clips (at the top of the end tanks) are reused during the installation of the Mishimoto unit.
Mishimoto 6.4L Radiator, Version 2
You’re looking at the second version of Mishimoto’s immensely popular 6.4L Power Stroke radiator. The cross flow-design, all-aluminum heat exchanger is capable of dissipating heat much better than the factory unit, and it’s proven vastly more durable than the updated units released by Ford. The radiator’s 2-row core design and increased core size effectively double coolant capacity (2.5 gallons vs. 1.25 gallons, stock), making it considerably more efficient in extreme working environments. The welded tabs on the front of the end tanks serve as mounting points for both the aforementioned transmission cooler and A/C condenser.
TIG-Welded to Perfection
To eliminate the end tank problem completely, the end tanks on the Mishimoto radiator are all TIG-welded. Constructed from aircraft-grade aluminum, tank wall thickness checks in at 0.098 inches. For version 2.0 of its radiator, Mishimoto increased core support thickness by 33 percent to keep the core from flexing when faced with inputs from the truck’s chassis.
Quick-Disconnects Retained
A CNC-machined, factory-style quick-disconnect inlet and outlet make for a seamless integration with the factory upper and lower radiator hoses. Also notice the mounting peg along the end tank, which features a co-molded rubber over the top of the aluminum peg. The rubber is new for the second rendition of the company’s radiator and is designed to limit the truck’s torque transfer into the radiator by providing flex where it’s needed.
A Robust Core
Because the top and bottom rows of the Mishimoto radiator’s brazed aluminum core see most of the stress as far as the core is concerned, internally strutted tubes are present in the top and bottom eight rows for superior strength in this area. Dimensionally, the radiator core is massive, measuring 37 x 27.5 inches.
New Hardware
Although much of the OEM hardware is reused during the install (thanks to its direct, drop-in replacement design), Mishimoto includes just eight M6 x 1.0 x 14mm bolts. However, the company also supplies a slick, magnetic 6061 aluminum drain plug with a Dowty oil seal.
Direct, Drop-in Replacement
Essentially a 40-pound, 46 x 29-inch rectangle, the Mishimoto radiator is a bit awkward to install by yourself, so make sure you’ve got a helping hand to squeeze it into place in the truck. As you can see in the photo above, the factory fuel cooler can simply be detached from the radiator and allowed to hang during the radiator swap.
Further Reinforcement
For the ultimate solution to the radiator-damaging chassis flex the ’08-’10 Super Duty’s are known for, Mishimoto also offers a robust replacement for the flimsy OEM upper radiator support bar. Mishimoto’s support bar features an all-steel construction, with welded tubular steel used in the center sections and cast anchor plates for mounting. Additionally, Mishimoto’s upper support bar provides enough clearance for a larger cold side intercooler pipe—an extremely popular bolt-on in the aftermarket.