High Temps after Mishimoto RAD install

eiorg9 · Apr 7, 2015

Ok so i am hoping that i will be able to get some answers on here bc im completely lost at this point. I installed a new Mishimoto radiator on my 6.4 which has 160,000 miles to date. I did the install and replaced any part that looked worn out and all the parts that were for sure worn out including the RAD hoses. Upper and lower. When i first put the truck back together and buttoned it up i was having issues with the RAD hoses sealing so i just went ahead and replaced them with the new updated RAD hoses from Ford. Well my truck still was acting completely normal until it would get to about 190 degrees and then would spike all the way to 240 degrees. I returned the upper RAD hose and ford gave me another one in its place ( so that makes 2 new "updated" RAD hoses i have tried). So i got it back buttoned up again today with another brand new set of Thermostats in there and basically the same thing happened. For about 10 minutes my truck felt and ran perfectly normal. Then it would get to 196 Degrees and would spike to 236-242 degrees in a matter of seconds and then i would have water coming out of the top of the degas bottle which tells me the PSI is getting WAY to high. So when i got home i noticed that the upper rad hose, where it connects to the Mishimoto radiator, had about a quarter inch of play in it and wasnt sealing correctly. Since i have literally replaced every other thing, i just dont know what else it could be. I called Mishimoto and sent them a video of what i have just explained and did not hear back from them at all. Hopefully i will tomorrow but as i sit here, without a drive-able truck, im just really questioning going with a Mishimoto Radiator as i never had these problems before making the switch. I have really loved the Mishimoto brand and im sure this problem could be fixed with their new silicone RAD hoses but they are $550 and i cant do it right now espescially after dropping $225 on these new "updated" hoses from Ford. But since there is SO much wiggle room im about convinced that Mishimoto made their radiator to fit their RAD hoses which i was assured before buying the radiator that that was not the case. Im just beyond frustrated with the entire thing but has anyone else had an issue like this or does anyone else have any advice they can give me as to what else it could be. I was planning on buying a new Intercooler from Mishimoto next week but now i dont know what to do bc of this situation. Any and all help will be VERY much appreciated!

Radioflyer · Apr 7, 2015

How are you filling your cooling system? These trucks can be a tad sensitive when refilling coolant and can get cavitation easy.

Just curious, did you replace your degas bottle cap as well?

sideactiondiesel · Apr 7, 2015

I would say the front cover is in need of replacing .

lazlow · Apr 7, 2015

What was the reason for rad replacement? But it Sounds like an air pocket in the system. Make sure its bled perfect...only way i fill coolant now is with a vacuum filler. Worth every penny.

forcefed6.4ford · Apr 8, 2015

Definitely sounds like air in the system. Before pulling the front of the truck apart again. Top it up and let the truck idle up to temp. The temp will come up more slowly and prevent spiking. Also leave the be cap off while the truck come up to temp.

eiorg9 · Apr 8, 2015

Cody @ ATP Trucks said:
How are you filling your cooling system? These trucks can be a tad sensitive when refilling coolant and can get cavitation easy.

Just curious, did you replace your degas bottle cap as well?

Yeah i guess i am filling it up incorrectly then and yes i did replace the degas bottle as well.

eiorg9 · Apr 8, 2015

sideactiondiesel said:
I would say the front cover is in need of replacing .

what do you mean when you say the front cover? Are you referring to the Thermostat housing

eiorg9 · Apr 8, 2015

lazlow said:
What was the reason for rad replacement? But it Sounds like an air pocket in the system. Make sure its bled perfect...only way i fill coolant now is with a vacuum filler. Worth every penny.

i replaced the RAD bc i had a leak in my old Factory RAD and i also had a little rust in the system and just thought id rather put a ALL aluminum in there for longevity purposes. Im not familiar with the vacuum filling process. Is it something i can myself or is it something that i need to have done?

eiorg9 · Apr 8, 2015

forcefed6.4ford said:
Definitely sounds like air in the system. Before pulling the front of the truck apart again. Top it up and let the truck idle up to temp. The temp will come up more slowly and prevent spiking. Also leave the be cap off while the truck come up to temp.

Ok i am going to try that first thing this morning. Thank you very much for the reply. Thanks to all of those who have replied. i am very appreciative

eiorg9 · Apr 8, 2015

Thanks to all those who have replied. i for sure think all of you are 100% correct bc after just watching a video i saw that air usually gets trapped in the Heater Core bc it is the highest spot on the cooling system and yesterday when i was driving i was at 170 degrees and then i tried my heat and thats when i went from 170 to 240 in a matter of about 10 seconds so i am positive that you guys are correct. Thank you very much for responding and helping me but i was wondering do yall think that the upper RAD hose having play in it is continually allowing air in? I am scared to death of cavitation and praying i dont have that problem. i am not going to drive my vehicle until i am 100% sure the upper rad hose isnt compromising my system.

sideactiondiesel · Apr 8, 2015

Still thinking it needs a front cover. This system is not that hard to get air out of. We do 3-4 radiators a week at times and never have an issue.

I am willing to bet if you pull your water pump out you will see a erroded and ate out cover due to electolosis. It is caused by coolant going to and from dissimilar metals. Especially between stainless of the egr coolers "when not deleted " and iron of engine block then to aluminum radiator to go back into aluminum pump cover and goes all over again. This is mostly do to poor maintenance cooling system or filling with the cooling system with hard water and not distilled.

eiorg9 · Apr 8, 2015

sideactiondiesel said:
Still thinking it needs a front cover. This system is not that hard to get air out of. We do 3-4 radiators a week at times and never have an issue.

I am willing to bet if you pull your water pump out you will see a erroded and ate out cover due to electolosis. It is caused by coolant going to and from dissimilar metals. Especially between stainless of the egr coolers "when not deleted " and iron of engine block then to aluminum radiator to go back into aluminum pump cover and goes all over again. This is mostly do to poor maintenance cooling system or filling with the cooling system with hard water and not distilled.

I replaced the water pump about 6 months ago and that is kinda what lead me to do all of these upgrades. I have deleted my egr as well. But when you say front cover, what are you referring to? I dont claim to be a know it all and am always up for learning.

sideactiondiesel · Apr 8, 2015

I replaced the water pump about 6 months ago and that is kinda what lead me to do all of these upgrades. I have deleted my egr as well. But when you say front cover, what are you referring to? I dont claim to be a know it all and am always up for learning.

OK , The front cover of the engine. your water pump bolts to it. it will have pit marks in it leading up to the thermostat housing .

SEABEE08FX4 · Apr 8, 2015

Just bleed the air out, drive it crack the cap to burp it, top it back off and drive it some more. Repeat the process as needed until it will take no more, make sure to leave enough room in the degas bottle for expansion. If you have access to a vacuum bleeder use that, if not do the other method I mentioned and massage/ squeeze the upper rad hose to jar the bubbles out too.

eiorg9 · Apr 19, 2015

So to update everyone it was simply the connection between the RAD hose going from the thermostat housing and into the top of the radiator. it has about a quarter inch of wiggle room thus allowing air into the system. Which MISHIMOTO said they would replace my radiator but then completely started ignoring me and wont handle the situation so i was once a mishimoto fan but now due to their customer service, i am really starting to become ANTI. And, if it were the front cover i would have coolant in my oil so that cancels the cavitation issue out. But thanks to all who responded!

BBottoms · Apr 19, 2015

If there is enough 'wiggle room' to let air in it would be spewing coolant out since the system is under pressure. Pretty sure you have another issue.

HOOV3R · Apr 19, 2015

Very difficult to suck air into a system that has positive pressure. I'm with bigr, you probably have a blown head gasket or cracked head.

sideactiondiesel · Apr 21, 2015

if it were the front cover i would have coolant in my oil so that cancels the cavitation issue out. But thanks to all who responded!

:fustrate:This is not always the case. but you are welcome

eiorg9 · Apr 21, 2015

HOOV3R said:
Very difficult to suck air into a system that has positive pressure. I'm with bigr, you probably have a blown head gasket or cracked head.

well i will check that out but i would be losing the coolant due to it being burnt right? Im not losing any coolant so that is why i did not think it was the issue. Im gonna continue and go through the system and make sure and i def. should not have said he was wrong bc i appreciate any and all advice or suggestions.

eiorg9 · Apr 21, 2015

sideactiondiesel said:
:fustrate:This is not always the case. but you are welcome

I pulled the water pump and checked out the front cover and it was totally fine. even had my buddy who is the diesel tech at the local Ford shop come by and check it out. Im gonna go through the entire cooing system in the next 2 days. Im even thinking of going ahead and doing the heater core as well.