I’m trying to identify this part - 2015 6.7L coolant puddle under the driver's side (under the cab) of the truck- can anyone assist? I don’t believe this is a coolant filter - perhaps an aux pump for cab heat? DEF inline heater?

 

That is your fuel filter and the drop of fluid appears to be diesel. That filter, along with the fuel filter under the hood are supposed to be changed regularly. Every 15,000 miles if I recall correctly. Fuel filter part number is FD4615 (includes both filters).

 

That is the diesel fuel conditioning module. It’s probably a fuel leak you have. There are 4 fuel line fittings on top, as well as the plastic bowl. The source of the leak could be a number of things, probably just need to dive in and investigate.

 

Diesel and Coolant can be the same color, but there are no coolant lines on the drivers side. You may need a new DCFM, which is what is in that picture.

 

The DFCM, like stated the "diesel fuel conditioning module" or the primary fuel pump, primary fuel filter with water separating media on the inside with the WIF (water in fuel) sensor on the bottom as well as the drain.

Like mentioned, 4 fuel lines and connectors up top. There are also two tabs that meet up when the lower part or cap is tightened down correctly after the filter is replaced. One is the cap and one is on the top of the DFCM. They can be overtightened and the tabs broke. Also, the cap gasket or seal, needs to be removed with a screwdriver or pick and the new one installed onto the top part of the DFCM. Do you recently have a filter set replaced?

Also, putting fresh engine oil on the new seal and threads of the top of the DFCM makes the bottom cap screw on much easier to get those tabs lined up and touching... learned that here from a Ford Tech.

 

Make sure the yellow drain valve is fully tightened. The first time I got a WIF I didn’t do that - previous pickup was a 6.0 with solid metal drain and I was worried about overtighening this one - and it started leaking due to dirt inside. That then put air into the high pressure side which took a lot of purging, and all within 24 hrs of purchasing 😳

 

Be sure to prime the system before turning the engine on when you replace the filters.

 

Forgot to mention that... good point.

It says 6 priming cycles, about 30 seconds as you will hear the pump shut off, I do 12 cycles at least. I didn't like the first time I changed my filters and did just 6 cycles. Engine took a few seconds to start. Now with at least 12 cycles, starts right up.

 

Same here. I Prime it around 10-12 times If it is quiet outside, you can actually here the bubbles purging.

 

that’s what I do as well, purge until the pump goes quiet.

 

I can also...