I had a mechanic replace the factory radiator almost 3 years ago with a Mishimoto radiator and just a couple weeks ago it started to leak on the driver's side. I can't pin-point where the leak is at due to all the hose, shrouds, etc that are in the way, but it will leave a small puddle (4-5 inches in diameter) on the shop floor. The truck is tuned with a mini maxx, however it is not abused, the truck is used for business and usually has a 14' enclosed trailer behind it that weighs approx. 5-6K lbs. Have also done the EGR and DPF deletes. There are 88K miles on the truck at this time.
Has anyone else seen these Mishimoto radiators leaking? It appears that they may have some issues with all the questions that they ask when submitting a warranty claim. Are there particular areas that I should be looking on the radiator for the leak areas? What about other issues that may lead to a premature failure of the radiator?
Just want to be sure to take care of the truck so that I don't end up with a major repair. Any help is greatly appreciated!

 

I thought my radiator was leaking as well. I carefully cleaned everything and let it idle in the garage on a clean floor.

Shut it down and crawled under it with a bright flashlight and an inspection mirror and followed the trail.

Turned out to be the lower rad hose at the block. The factory hoses have been replaced with double oring style fittings because of this typical failure.

I put mish hoses on and the problem was resolved.

Denny

 

Thanks DieselDenny! I should have mentioned that just less than a year ago we replaced the hoses with new ones when doing the EGR delete.
I tried to follow the leak, which runs down across the frame, to the snow plow mount onto the floor. Appears to be in behind the lip of the fan shroud, but not sure how far up.

 

worn front body mounts allow flexing which results in the radiator being used to box in the chasis beams. after you fix the leak, you can install a front trailer hitch if you do not have a front plow hitch installed which will box in the front end taking the radiator out of the flex picture.

I had a leak that I could not find....I installed a coolant filter and the leak stopped. theory is the grime/grit ( which there was plenty of) was interfering with the pump seals. it has not leaked in 5000 miles since adding the coolant filter and to this day I still do not know exactly where the leak was coming from.

 

I do have a plow hitch or mount on my truck, so I am thinking that should help stiffen the flex between the frame rails.
I have heard of the coolant filters, just wasn't sure if that is necessary on the 6.4L and I haven't researched it either, so I am open to this if it will make a difference.
The radiator is under warranty, but they want to use their liquid chill stop leak as a first step. A little concerned that introducing this may lead to other issues. Thoughts?

 

Mishimotos are also failing at the same rate the factory ones are. This is "suppose" to be the fix:

https://m.thoroughbreddiesel.com/mis...FZA8gQodXdEAIg

 

Just had an event with the stock radiator.

45 miles from home towing a light 5th wheel to go 200 miles for the weekend and meet the kids.

I see steam in my side view and pull over. Yup, the radiator separated on the drivers side half way up.

Flat bedded it home for 310.00 and picked up my 7.3 E99 to finish the trip.

That ole girl with 220k on it pulled it off like a boss and saved the weekend (two daughters and a wife kinda thing that you don't want to let down)

Anyway, now I'm researching and am needing advise......

Good friend is an expert metal fabricator and can make me stiffeners for the frame and core.

Which radiator/ core support would be the best choice. I want to say money is no object for a good feeling away from home towing, but I don't want to make another bad investment only to be let down.

Your experiences and wisdom are appreciated.

Denny

 

Well, my radiator leak has lessened to almost nothing after adding coolant last week. I haven't poured in the Liquid Chill stop leak yet. I really am hesitant to do this and risk causing some other issue in the cooling system.
How new is the support stiffener? Has there been enough testing to show that this support solves the leak issues? I know this would mean that you would have to install the support and the new radiator at the same time.
We are upgrading campers to a 37' 5th wheel and don't want to have issues with the radiator now that we will be using the truck for some heavier pulling.

 

Don't add stop leak. Oil cooler doesn't deserve that kind of abuse!

 

Hey everyone, thanks for the comments. We're well versed in the issues that plague this truck and wanted to jump in to provide a bit more context on what Mishimoto is doing to help keep 6.4L owners on the road.

First, let me say that we are willing to honor our lifetime warranty on all Mishimoto Ford 6.4L radiators. A while back, we had purchased a 6.4L truck from a customer that had gone through numerous OEM and aftermarket radiator failures in efforts to research the root cause and provide a solution to the community. From our research, the chassis flex can lift the radiator and allow it to flex. This ultimately leads to a failure in the radiator. On top of making the radiator more rigid, we currently produce replacement lower bushings which are included with the radiators at this time. If you purchased your Mishimoto radiator before these lower bushings were offered, we can send you a set at no charge. The bushings are made from polyurethane and are thicker than the OEM rubber bushings to allow for the radiator to sit more snug and secure in the chassis.

Along with the bushings we also released an upper support bar that is made from steel to replace the aluminum bar from Ford. This steel bar helps increase the rigidity of the front end of the truck to help minimize the flex in the system. We have been testing this combination for about a year now without a single failure in our truck. We have also sent out prototypes to a few shops and end customers for additional real world testing. So far, the feedback has been overwhelmingly positive. We even went through lengths to put the upper support bar through the ultimate stress test, lifting an entire 6.4L engine in the video below.


At this time, we feel that we are currently doing everything we can to engineer a solution for the issue that Ford has ignored. We understand that our customers love their trucks and they don't believe the solution is to go out and purchase a new truck. The improvements mentioned above represent a huge step towards solving these chassis flex issues once and for all. In the meantime, we’re keeping a close eye on the results and feedback our customers provide; ultimately backing everything with our Lifetime Warranty.”


-Mishimoto

 

Well, my Mishimoto radiator has started leaking again. It is leaking at a much greater rate than what I saw last year.

 

 

In my eyes if you go the long dollar on a radiator that's supposed to fix the problem. Warranty aside, they're engineers are missing the boat on the construction of known weak points.

Sure, we'll guarantee it for infinity, but you have to bust your *** to dig the nose of your truck off, pay for towing and new coolant etc.

The proper fix would be to spend a few dollars more on the construction and material mils and absorb the fact that the radiator racks in the frame despite putting diapers on fords engineering problem.

I opted to go aftermarket and bought two.

Denny

 

 

I've had a front tow hitch for over 3 years now. I went through 4 radiators before I installed it. Currently on the last cheap aftermarket radiator that was installed, and it hasn't leaked. I've even been through head gaskets etc, and still no leak at the radiator. I recently installed the Mishimoto radiator support to add more strength and because I'm a sucker for aftermarket parts. So far, no leaks. Wish I could say the same for my hydrobooster..lol