My biggest question overall is, for those of you that have had repeated failures with Mishimoto, when you switched to another radiator, has the problem gone away? Everyone wants to point a finger in frustration, but I haven't seen a case where someone stops using the Mishimoto and uses another radiator and the problem doesn't occur again. I've inferred it from some of the stories, but I'd be interested to see if anyone has a different experience. Also, what did you replace it with?
I had two Mishimotos leak on my OBS, both failures were mirror images of each other. Got a refund and went with the cheapest plastic tanked rad I could find on amazon. I've had no problems since.
Once when one of my Mishimoto 6.4 rad left me in a bind on a Friday, I used one day Saturday shipping to get a plastic tanked rad from Amazon so I could replace it on Sunday (working 6 days a week a hundred miles from the house). The Mishimoto replacements ususally take about 10 days to get to me in PA.
It worked very well until the temps went below zero, it would leak. The end tank would separate from the fins. If it was 4F, it would not leak, as soon as it went below zero, it would leak again. So with this now happening, unusually cold temps, and my replacement Mishimoto having showed up after the warranty process, I put it in.
I was driving 108 miles one way to work and close to 300 miles total a day, so I had to have the truck as reliable as possible.
The leak (lower passenger side) of the plastic tank rad did not mirror that of all the failures of the Mishimotos I've had. I do not believe it was caused by the truck flexing, which I believe is causing the Mishimoto failures. All my Mishimotos have failed in the same location (about 4 inches down from the top, drivers side). It's been deja vu after deja vu.
The factory rad in my 6.4 lasted about 42k miles. That was 42k miles without the Mishimoto list of new/updated parts that are supposed to promote rad longevity. If my version 2 Mishimoto fails, I'll probably ask for a refund and go back to a Motorcraft OEM branded rad but I really have no faith left that any brand/style rad will hold up in my 6.4.
, if I were you, I'd go factory. Good luck with what you choose.
Forgot to mention, I've got most of the changes done to "prime for success" like you mentioned. Poly urethane body mounts, updated hoses, the only thing I don't have is the latest single port degass bottle. I am not convinced though that any of these updated besides the body mounts would make a difference. Most of the updated components are recommended to prevent pressure spikes/oscillations. One of my Mishimotos was abused with 24 psi of pressure when my head gaskets were leaking. It held up just fine to all the pressure. I could make it puke tons of coolant on command and 24 psi was the highest I saw on my makeshift coolant pressure gauge.