Looks like Ford added a bypass valve on the secondary fuel filter for improved cold conditions.

FD21-MC-ColdWeather-Diesel-Fuel-Filter-v5_a11y.pdf (powerstrokediesel.com)

 

Interesting. I started my truck without using the block heater a few times last winter (-12) without any problems. Most of the time I use a timer connected to the block heater for quicker warm ups. I wonder if the fuel starvation they mention has a negative effect on the CP4?

 

So the injectors are going to take over the role of filtering particles below 10 microns….that can’t be good


a few months ago I added a filter in between the engine bay and tank filter…had an engine bay filter that was less then 3k miles crack…in seeing this…I’m glad I did.


ford solves one problem to create another

 

Yeah gelling can be a big problem for the CP4, especially on the unpinned buckets on the 2011-19, get that thing turned 90*s and the will be toast in short order.

The OEM fuel system provides three times more fuel than required. My understanding is the bypass cuts down on the amount of fuel being returned to the tank and recirculates previously filtered fuel to the CP4. I could be wrong. I can't imagine Ford pushing 10 micron filter fuel to the CP4 and expecting sufficient wear rates.

BTW, where did you tap in for the addition fuel filter? I am thinking about scrapping the OEM set up and going the 1-14 threaded filter head route now that I am out of warranty.

 

The block heater heats the coolant in the block, Allowing the engine to warm faster. It doesn't heat the oil in the oil pan and it doesn't heat the fuel in the tank.
The fuel gets heated as it passes thru the system on the engine and the excess fuel is returned to the tank. Slowly warming all the fuel

 

it would be good to see an animation of how the bypass valve works.

I installed something similar to this on the frame rail under the drivers side. I use the bolts that mount the transfer case bracket to hold it.

used some crimp clamps and got the correct fittings to extend the engine bay filter feed to my new filter, run a return from my new filter back up to the engine bay filter in. Later I plan to add a return line from my new filter to the tank return junction point.

my goal was to have an element that could filter between 4 and 10. My thought was that particles would accumulate in my new filter and prevent build up in the engine bay filter…preventing engine bay filter housing cracking.

if you add an in-between-filter, double check the micron ratings of the element…there is tricky math with the ratings …some use an 85% rating, some use an absolute number.

 

Looking a the small flow diagram it appears that the bypass is similar to a oil filter bypass and functions for the same reason.

 

Barf....nothing like pushing 10 microns of crap through a 6 micron hole.

 

im going to put on my ford aluminum genius cap for a minute

so the thought must be….all fuel is pure so bypassing the 6micron filter is okay…AND…the reason for the bypass advertised as a winter good thing is that the fuel gel particles will melt as it approaches the CP4….so the metering valve screen and the injector screens won’t get clogged from fuel gel particles.


genius hat off

but I suspect clogged injector year round will increase….another ford money grab.

 

Yeah, but..... I would rather not starve the CP4.2 pump of fuel. It's kind of what's the less of two evils. Pretty sure Ford implemented due to CP4.2 failures from fuel starvation.

 

I agree, when the filter gets clogged up with gelled fuel, then the bypass at least lets some fuel through. I can see the logic, as well. But, it's an issue only for those owners that operate in extreme cold, or temps that at least allow for fuel to gel.

I'm wondering if Ford will be replacing all former kits with this new one? I have no need for a bypass, as the temps don't get anywhere near as cold here in Texas. And, fuel additives can suffice for those temporary occasions where those kind of temps occur (which is very infrequently, here).

 

Yes I agree defiantly the lessor of two evils, still doesn't give you the warm and fuzzies.

I would assume this is across the board, I haven't see a new part number or amended part number issued. Dualling specs for a single part number is atypical. But I could always be wrong.

 

I have to imagine that the bypass works on pressure that if the filter plugs up with gelled fuel, then the bypass when it senses that and opens to allow unfiltered fuel to flow... Preventing starvation of the CP4 in frigid weather.

You warm weather folks have No worries because you normally don't have the colder temps to gel up the fuel. So it won't affect your filtration of fuel... Honestly, I'd rather have the bypass set up and working than to starve that Bosch pump. But I use the double dose (winter dose of 500 :1) of K100 so I'm not too worried as I haven't had gelled fuel since I've bought my truck... But that's just me and my 2 cents...