08 F-250 Repeat Radiator Failure

[PowerSToKed]

Its got 250000+ miles on it,  EGR system has been deleted (coolers as well),  DOC/DPF has been deleted,  it has double O-ring upper and lower hoses,  single port de-gas bottle,  new thermostats and water pump,  new front cab mounts,  no visible external coolant leaks.  The hoses,  reservoir, T-stats,  pump and mounts I've  installed at different times the past few months.  I've put 3 Mishimoto all aluminum radiators in it about 5000-8000 miles apart one after another with the leak being about 4 inches from the drivers side tank and about 4 inches from the top.  The customer wanted to try a Alradco all aluminum radiator at this point,  about 8000 miles later is now and it is leaking around the same place.  I've been using Rotella ELC coolant and at some point after replacing one of the radiators,  I checked cooling system pressure - stabilized around 14/15 psi but no major spikes at wot.  Thoughts,  opinions,  advice...

[lmorris]

First thing that jumps out at me is cooling system pressure. 14-15 PSI is the typical release pressure of the cap. Normally these run no higher than 8 PSI. Is it purging coolant under loads? If the level drops low enough to aerate the coolant, that could be your cause. How did the front cover look behind the water pump? 

[Matt Saunoras]

A solid aluminum radiator isn't going to do any good in a 6.4.  The Mishimotos are leaking left and right.  Alradco is going to suffer the same fate. 

[Matt Saunoras]

With that many miles think about replacing the cab mounts too. 

[Keith Browning]

Funny thing is that I cant remember when the last stock 6.4L radiator I replaced was.  I did come across one leaking this summer and it also had leaking hoses - of course the customer declined the repair. 

With that many miles think about replacing the cab mounts too.

I do recall us discussing this some time ago and someone commenting about body flex and subsequent stress on the radiators possibly having something to do with repeat failures. They always seem top leak at the tank seams so perhaps there is something to that.

[Aaron]

Bill Hewitt has a blurb all about this on his page.

 

With your cooling system pressure behing so high I would lean towards head gaskets.

[Keith Browning]

I don't see 14/15 PSI as being a problem. IMHO. Why do you Gents not think that this is normal on a truck at full operating temperature? Seems to me that 8PSI is somewhat abnormal. "No pressure spikes or venting reported" kinda eliminates a head gasket concern in my mind especially on a 6.4L which is not necessarily known for head gasket problems. While there are some modifications listed there is no mention of performance add-on's or raised power output. Remember that the system pressure is necessary to raise the boiling point of the coolant approximately 3 degrees* F  per 1 PSI coupled with the fact that a  50/50 mix of ethylene glycol based coolant/Water will raise the initial boiling point to 106 C / 223 F... add 15 PSI and that raises your boiling point to over 268 F.

 

Another thing to consider is that when you start modifying the cooling system by removing things and changing the system flow you can cause problems by speeding up or slowing down coolant flow in places inside the engine. This can cause hot spots and localized boiling which will also cause pressure spikes and pulsations... you know, like the conditions Ford states causes radiator concerns due to low coolant, damaged t-stats, leaking hoses and so on. Modifications... I am constantly amused that many of these truck owners that insist on removing stuff and putting on all kinds of aftermarket goodies that promise improved performance and reliability often find themselves with more problems in the end. Not too sure if it's the products or the approach.

 

So, in my opinion I would want to know what the operating temperatures are, is my fan working, good airflow, coolant pressure spikes, coolant type and concentration and the quality of the radiator to begin with.
 
Where am I going with this? Just thinking out loud... then again, Aaron is quoting Bill Hewitt 

[blown99]

I don't see 14/15 PSI as being a problem. IMHO. Why do you Gents not think that this is normal on a truck at full operating temperature? Seems to me that 8PSI is somewhat abnormal. "No pressure spikes or venting reported" kinda eliminates a head gasket concern in my mind especially on a 6.4L which is not necessarily known for head gasket problems. While there are some modifications listed there is no mention of performance add-on's or raised power output. Remember that the system pressure is necessary to raise the boiling point of the coolant approximately 3 degrees* F  per 1 PSI coupled with the fact that a  50/50 mix of ethylene glycol based coolant/Water will raise the initial boiling point to 106 C / 223 F... add 15 PSI and that raises your boiling point to over 268 F.

 

 

 

I agree 100%.  The cap is a check valve.  The system is supposed to run at the rated cap pressure, then bleed off excess pressure from that point on.  You may not reach the caps rated pressure on a basic road test, but load the engine and you will see every tight cooling system will get to that pressure.  Pressure spikes are a different story though.

Good info on the mishimoto.  I installed one for a guy in April.  It lasted 4 months, now leaking on the driver side, about 4" up.  Kind of looking like it is coming out of the weld.  Waiting for him to come back in so I can replace it under Mishimoto's BS warranty.

[Brad Clayton]

It would appear to me that the only acceptable radiator for a Super Duty chassis is a down flow design. In 25 years, I have never replaced a pre 08 radiator that was just bad and leaking. The ones I have replaced were customer induced failures.

 

The wide or in a 6.7 very wide horizontal flow radiator definitely can't hold up to much articulation or frame flex.

[forddieseldoctor]

It would appear to me that the only acceptable radiator for a Super Duty chassis is a down flow design. In 25 years, I have never replaced a pre 08 radiator that was just bad and leaking. The ones I have replaced were customer induced failures.

 

The wide or in a 6.7 very wide horizontal flow radiator definitely can't hold up to much articulation or frame flex.

 

Um... I have seen quite a few 6.0 radiators that leak at the top tank seam. Both F and E series. But still not near as many as the 6.4's and 6.7's.

[Aaron]

My truck is on its 3rd.

 

It's not a ford one this time. See how this one holds up. (Life time warranty thoigh so I will just be out my time to change it next time)

[Aaron]

First one went ~100k miles. This last one made it ~40k miles I think.

[Aaron]

Oh. So that aftermarket rad I bought? It took a shit.

 

I put another Ford one in it to the tune of $1000 my cost by the time all the smoke cleared. New stats again.

 

I got my money back on the aftermarket one because they couldn't supply me with another one, no stock anywhere.

[Fordracer]

What brand was it Aaron. I have a customer that wants to put in an aftermarket one.

[Aaron]

Spectra.

 

And the ford one that I replaced it with just started seeping in the lower left corner. Fuck me.

[Keith Browning]

Are you folding them when you install them?

[Brad Clayton]

I usually wad them first.

[Aaron]

You mean they're not supposed to be folded?