After jumping into the diesel truck market a few years ago, Mishimoto designed and released an aluminum radiator engineered specifically for the Ford 6.4L. We identified a serious concern with stock radiator failure. Numerous enthusiasts on a variety of online boards were experiencing extremely frequent failures, with some folks replacing as many as 3 radiators within the first 60,000 miles. In fact, this issue in combination with others that plague the 6.4L were enough to make a few truck owners revert to the previous 6.0L or upgrade to the newer 6.7L, swearing off the 6.4L after repeated issues with their trucks.
Being experts within the automotive & diesel cooling world, we immediately saw an opportunity to provide a solution for this problem. Our engineers designed an aluminum replacement radiator which provided a far more rigid construction, full aluminum, and still incorporated all of the stock quick-disconnect fittings. Our initial investigation regarding the stock radiator showed that most were failing near the end tank connection which was a plastic crimp-style connection. From our understanding, either this stock unit was not equipped to handle the pressure created by the 6.4L cooling system long-term. Another possibility was a poor material choice for the stock radiator end tanks and/or crimp connection components. By manufacturing our radiator from aluminum, we were eliminating any of the concerns we saw with the stock radiator.
Thus, the Mishimoto 2008-2010 Powerstroke radiator was born. We began shipping these units out to customers and immediately had a ton of great feedback. Our customers were very pleased to rid their truck of the stock radiator. Additionally, as with all our products, we included a lifetime warranty with this radiator.
Over time we continued to receive great feedback from a high percentage of our customers. For all of our products, we keep a very close eye on defect rates to ensure that our products are falling within our standards (which are far below industry standards).
Enhancing Our Existing Design
We began to see a few warranty claims trickle in for this particular radiator. It appeared as though a small portion of our customers were still experiencing issues even after switching to our product. We honored our lifetime warranty and had numerous failed units shipped back to our HQ in DE to inspect the failures and see if we could identify any concerns or common trends.
During our investigation of defective units, we researched the stock radiator system and failures a bit further to see if we could make any correlations between the failures of our units. We also brought several trucks into our facility to inspect the cooling system and chassis. Several other sources indicated that chassis flex may be playing a role in radiator integrity. Soon after this, we put together a radiator checklist which provided insightful tips for folks experiencing repetitive radiator failure. This list included a variety of Ford issues TSB’s, inspections of several components, and replacement of failed or outdated parts. This report is linked below.
One of the more prominent concerns within this list was in terms of the body/cab mount bushings. From our research and vehicle inspection, we saw that these bushings are quick to degrade over a very short period of time. Additionally, we saw that once these bushings were compromised, chassis flex was being transferred to places it shouldn’t be, primarily the radiator support beam. This flex would then torque and twist the radiator even during normal driving conditions. As you can imagine, flexing of the radiator in such a way is not particularly a good thing. Take a look at some of the images below showing the mounts we pulled from out test truck compared to stock mounts.
Several of our customers replaced these bushings along with our radiator and were able to solve their particular radiator failure concerns. That being said, a small percentage of customers who had completed our checklist and had intact cab bushings were still showing failures with our radiator. This news necessitated immediate action and we began to tackle a new prototype radiator which featured a more rigid design internally, yet provided greater flex at the support contact points. Even though this sample of customers was small, we wanted to be able to offer a solution for all 6.4L trucks on the road.
Our design changes effected three different portions of the radiator.
- Upper radiator mounting points
- Internal radiator tubes
- Radiator core support plates
Each change is described in greater detail below.
Upper Mounting Point Modification
The first goal with this redesign was to better isolate the radiator from flexing due to chassis movement. Although the stock upper mounts use a rubber bushing to connect them to the radiator support on the truck, the posts are a solid component. To produce greater flex here, we decided to utilize a rubber mounting post instead of the solid aluminum post on our first design.
For initial design stress testing, we made a few prototype units to install to verify fitment and evaluate the amount of additional flex and movement we would see with the revised post.
We evaluated several durometer rubbers to ensure we were providing an ideal blend of flex and rigidity.
This particular modification will work in conjunction with the design changes in terms of strength noted below to provide far greater reliability.
Internal Tube Revision
Our 6.4L aluminum radiator is a 2-row unit and provides a massive increase in core size and overall fluid capacity (capacity is doubled). These size increases were incorporated into our design to provide greater heat transfer and cooling efficiency. As with most of our radiators, our initial product utilized a standard oval shaped tube. For a majority of applications seeing the pressure of an automotive/truck cooling system pressure, these tubes provide ample support. For added strength, these tubes can be strutted creating what is called Harmonica tubes. This will provide greater pressure tolerance as well as a more rigid tube. The differences can be seen in the image below.
Although this is not the actual core from our 6.4L radiator, the tube style will be identical. We will be incorporating these strutted tubes in the top and bottom 8 rows of the radiator. These portions of the radiator incur the greatest stress, which explains why most failures happen in this area. We expect this change to make a substantial difference in longevity.
Radiator Core Support Plates
The core support plate is the portion of the radiator which envelops the core. On the 6.4L radiator, these are on the top and bottom being that the Powerstroke radiator is a crossflow unit. This is shown in the image below.
For added strength and to reduce the chance of the core torqueing and bending, we’ve increased the thickness of this piece by 33%, effectively increasing the rigidity. This modification along with the adjustment of the tube design are in place to strengthen the overall radiator design.
This is the portion of product design which caused a delay in releasing our revised design. We were making some pretty significant changes to this radiator and we wanted to ensure that these changes would solve the 6.4L radiator dilemma. Our customers experiencing failures with our first design were becoming frustrated, as were we, and we needed to provide them with a solution that would cease the frequent radiator replacements on their trucks.
To be sure we had a fix for the problem, we reached out to several of our warranty customers who were experiencing issues with our first design. We requested that they perform some on-road testing of our new prototype to help validate our design changes. We also worked with a few shops to acquire test vehicles for some additional data points.
Several months of road testing ensued, and we are pleased to report 0 failures with our new prototype. Keep in mind that these customers had already been through a stock radiator and at least one of our V1 radiator designs. We can accurately say that this radiator will provide far greater reliability compared to the stock radiator and our first version of this unit. As with our previous product, we still recommend ensuring all vehicle TSBs are up-to-date and the cab bushings are intact.
With months of testing in the books and some very pleased 6.4L owners, we are pleased to announce the release of version 2 of our 6.4L aluminum radiator. As always, we will be keeping our eye out for any warranty returns and we will be staying in-touch with our beta testers to ensure they continue to have leak-free operation.
Our first batch of units have already been shipped out to warranty customers and we are expecting a second batch of units in the coming weeks. All current products shipping from our warehouse will feature the revisions detailed in this article. For those who are expecting a warranty replacement within the next few weeks, it is very likely our revised design is on its way to your doorstep.
Below is a look at the new product!
We truly appreciate the support and patience from the 6.4L collective in regards to our radiator design changes. We have been working tirelessly to provide the absolute best radiator solution and we are very confident that is what our team has created. For those who were within the small group effected by continuous failures with the Mishimoto radiator, I apologize for the inconvenience you experienced.