First introduced in 2008, Ford’s 6.4-liter Power Stroke engine has become a front-runner in the performance diesel market, able to make more than 600 rear wheel horsepower with nothing more than simple bolt-on upgrades. The 6.4 performs strongly in stock-class dyno competitions and holds its own drag strips and sled pull tracks across the country, all while still keeping its good streetablilty and impressive towing potential. 

But like anything else, there are bound to be weak links in the system. As owners started putting more and more miles on their 6.4L trucks, many returned to their Ford dealers complaining of high coolant temperatures, leaking radiators and coolant hoses, and degas bottle problems. While Ford has issued multiple revisions to alleviate some of these issues, the aftermarket has stepped in to ensure the cooling issues can be resolved once and for all.

Mishimoto has been a leader in performance cooling products for cars and bikes since 2003, and they’ve recently jumped into the light duty diesel truck market with product lines for the Dodge/ Ram Cummins, GM Duramax, and Ford Power Stroke engines. As automotive enthusiasts themselves, they could see the need for a superior Power Stroke radiator with improved durability and efficiency. Through countless hours of engineering and testing, Mishimito has released an all-aluminum radiator upgrade to replace the failure-prone OEM plastic end tank unit. While developing the radiator development, the Mishimoto team also found a need to increase the efficiency of the factory intercooler, particularly in high-horsepower applications that push large amounts of air through the stock core.

NOTE: We performed this test with the Version 1 Mishimoto Direct Fit 6.4L Powerstroke Radiator. Since then, Mishimoto has released a Version 2 Direct Fit 6.4L Powerstroke Radiator. The Version 2 Radiator was designed to address even more of the flexing issues found in 6.4L Powerstroke trucks. New features include co-molded aluminum/rubber mounting pegs to reduce the truck’s torque transfer to the radiator, along with internally strutted tubes in the top and bottom 8 rows for increased strength against high pressure and temperature. The top and bottom core support plates have also been strengthened to prevent core torquing and bending.

For more information, please follow this link: Mishimoto.com/ford-6-4l-powerstroke-aluminum-radiator-08-10.html


The Mishimoto unit is a direct replacement unit that fits into the stock location with no modifications to the truck required. Custom machined hose ends accept the factory quick connect coolant hoses and all factory mounting locations are retained so that the stock transmission cooler and A/C condenser can be remounted easily.
Constructed from high-strength aircraft-grade aluminum and covered by a lifetime warranty, the Mishimoto radiator has a brazed aluminum core that offers superior durability and efficiency to help keep the big Power Stroke engine cool under harsh driving conditions. The larger TIG-welded aluminum core and end tanks also allow for a 1.25-gallon increase in capacity. With this increase in fluid capacity and a superior core design, customers can expect more consistent fluid temperatures and better heat dissipation, which should improve the engine’s performance and efficiency, especially while towing over long grades in the hot summer months.


With factory-installed compound turbos, a tuned 6.4L Power Stroke can move some serious air. At 40+ psi boost pressures, the charge air temperatures climb rapidly, which reduces air density. While the turbos may be moving more air, that hot air is less effective in the combustion chamber and equates to a less efficient burn and higher exhaust gas temperatures. To combat this, Mishimoto developed an intercooler for the 2008-2010 Ford that can be installed in less than 30 minutes, even by a novice mechanic. The larger intercooler uses heavy-duty cast aluminum end tanks and a more efficient bar and plate core, and MIshimoto claims it can drop intake air temperatures by more than 20 percent.

Hot-rodding a 2008-10 Power Stroke 6.4 puts heavy demands on the factory radiator and intercooler. We’re replacing both on this 2008 Ford with components from Mishimoto. Installation begins by disconnecting the batteries and draining the coolant. We must remove several layers of coolers in order to get to the radiator.

During in-house dyno testing, Mishimoto’s test vehicle showed charge air temperatures increasing from a constant cruise temperature of around 100 degrees to more than 140 degress at wide-open throttle with the stock intercooler. With the larger Mishimoto unit installed, they claim that cruising temperature dropped by 6-8 degrees with maximum temps increasing to just over 110-degrees on a long pull. This 25+ degree drop in charge air temp can yield major improvements in the combustion chamber and equates to a 100+ degree drop in exhaust gas temperature. Engineered to provide substantial benefits on a stock truck, the cast end tanks can also support the higher boost levels found in highly modified trucks. Like their radiator, the intercooler is backed by a lifetime warranty and is offered in shiny bare aluminum or stealth black powder coat. Installation instructions and a step-by-step video are posted on the Mishimoto website.

Let’s follow along as a Mishimoto radiator and intercooler are installed on a 2008 Ford Super Duty. Mishimito rates this installation at a three-out-of-five, as the cooling system will have to be drained and several parts need to be removed to gain access to the radiator (and since the intercooler must be removed as part of the process, this is a great time to upgrade it as well). The complete project should take about four hours, not including the time required to update your factory coolant hoses, thermostats and degas bottle (updates had already been carried out on our 2008 model installation truck). Mishimoto has full step-by-step videos on their website to help owners decide if the job is within their capabilities.


After installation of both the performance radiator and intercooler, our test truck owner reported the constant coolant leak problem had been resolved and his coolant temperatures now peak 5-6 degrees cooler than the stock while towing over steep grades, and that those temperatures fall back down to the normal operating range much quicker. With the new intercooler, EGT is reduced by nearly 125 degrees under wide-open throttle and almost 75 degrees while cruising. If you find your 6.4L Power Stroke is in need of some attention as the stock cooling system starts to show signs of weakness, Mishimoto has the products you need. DW

2 The driver’s side intercooler tube attaches from the underside of the truck, directly behind the bumper. Take the time to clean debris and oil out of the pipe and boot in order to ensure a leak-free seal during reassembly. This connection is notorious for coming apart and causing a loss of boost pressure.
3 The intercooler is held in place by two bolts that attach it to the radiator core support.
4 When removing the intercooler bolts, exercise care with the rubber isolators, as they will need to be reused and installed on the new Mishimoto unit.
5 If there’s a cooler attached to the driver’s side of the intercooler, remove it as well. The intercooler can be lifted straight up out of its lower supports. With the intercooler removed, the transmission cooler and A/C condenser can be moved aside.
6 Since the radiator core support will also be removed during this process, now is a good time to remove the hood latch mechanism. A small pair of pliers can be used to disconnect the steel cable at the lower hood latch handle.
7 Before removing the hood latch, mark its position on the radiator support so you can easily realign it during reassembly. Then unbolt and remove the hood latch.
8 The transmission cooler is completely disconnected and set aside. Be sure to have a small bucket handy to catch residual fluid draining from the lines. Most home mechanics won’t have access to an A/C machine, which precludes removing the condenser; luckily there’s enough give in the lines that it can be rotated and set atop the engine. With all the other coolers removed, we can get a good look at the factory radiator… it’s massive!
9 The factory coolant hoses can be disconnected from the radiator by simply sliding out the small metal U-clips with some pliers. Even though the radiator was drained, the lower radiator hose will still be full of coolant, so by disconnecting it from the radiator and not the engine, you should be able to avoid taking an antifreeze bath.
10 Before you can remove the radiator, the upper fan shroud will have to be removed. With everything out of the way and disconnected, the radiator can be hoisted up and out of the chassis. Consider enlisting the help of a friend for this step. The large radiator can be cumbersome, and it may still have some coolant inside; extra hands can help keep the mess to a minimum.
11 The new Mishimoto radiator features full-aluminum construction with TIG welded end tanks to prevent leakage issues that are known to plague the factory unit. Along with its more robust construction, the Mishimoto unit also adds capacity, holding 1.25 gallons more than the stock radiator. The increased capacity and core design aid in heat dissipation for improved cooling efficiency.
12 Machined hose connections match the factory cooling hoses and allow the factory clips to be reused. While the new radiator is larger in size, it still fits in the factory location with no modifications needed to the truck.
13 The all-aluminum construction not only helps with durability, it aids heat dissipation as well. The factory 6.4L radiators have been extremely problematic for Ford and they have released multiple recalls with “resolutions” to the problem. The plastic end tanks in the factory unit are the real issue.

14 & 15 Before installing the new radiator, all of the factory mounting tabs and isolators need to be reinstalled. The lower pads fit directly into the brackets on the new radiator, while the upper supports slide over the posts welded to the end tanks.
16 The new radiator comes equipped with mounting tabs and bolt holes that match the factory unit. Mishimoto supplies some new installation hardware, including the pieces needed to attach the A/C condenser.
17 The small welded tabs on the end tanks hold the A/C condenser and transmission cooler firmly into place. Sadly, this is about all you’ll see of the big shiny radiator once all the parts are back on the truck. It seems a shame to hide such a pretty piece of fabrication behind all those factory fluid coolers.
18 The last part to the repair project is the installation of the Mishimoto intercooler. Coated in the optional black powder coat, the big core may appear to be stock, but its performance proves otherwise. According to Mishomoto, testing showed a 21 percent drop in intake air temperature and a 50 percent drop in pressure loss compared to the stock unit. Its 20 percent larger core is just what the modified 6.4L Power Stroke needs when it comes time to make clean, efficient and usable horsepower.


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