2015 Ford F-250 PSD 158.6k mi; Rotella T6 5W-40 5.3k mi

[Donald]

So about half way through this OCI the CP4 was upgraded to a DCR HPFP. And crankcase ventilation box replaced. Both as preventative maintenance.

Fuel dilution dropped dramatically.

158000 miles and 4103 hours at sample time.

 

[Donald]

I talked to the guy who did the upgrade to DCR HPFP and he has never seen fuel dillution improve this significantly due to an upgrade of the HPFP. And has done several. He is the diesel engine expert for southern Delaware.

The only other thing I have done is switch and consistently use Archoil diesel fuel additive. I am almost out of that and a container of Opti-Lube is next as my routine fuel additive.

 

[mattd]

Mine did not improve that much over the 6 months I had the DCR in. I’m going to say it’s driving conditions.

 

[Donald]

Mine did not improve that much over the 6 months I had the DCR in. I’m going to say it’s driving conditions.

First thought would be error at lab but the viscosity is fine, so essentially no fuel thinned the motor oil. I have used Rotella T6 5W40 before. So probably not the oil. I have started to consistently use Archoil but too big of an improvement for a fuel additive.

I drive mostly in towns and back roads. Not a lot of traffic and minimal stop lights. Mostly 50 MPH on back roads. Not a lot of highway.

Maybe my CP4 was really leaking and with that leak gone it's back to normal?

I am a little stumped as is the diesel expert in Southern Delaware who did the CP4 upgrade.

 

[johnmyster]

In theory, a HPFP could leak out the shaft seal and into the crankcase. I'm just not sure I've ever heard of it. Any other leak paths would be external.

2015 had no "indirect" injector, so regens contribute to fuel dilution.

Maybe your <1 sample was an error, or perhaps you ran it good and hot enough prior to the sample to evaporate any fuel, as opposed to sampling right after a regen.

 

[Donald]

In theory, a HPFP could leak out the shaft seal and into the crankcase. I'm just not sure I've ever heard of it. Any other leak paths would be external.

2015 had no "indirect" injector, so regens contribute to fuel dilution.

Maybe your <1 sample was an error, or perhaps you ran it good and hot enough prior to the sample to evaporate any fuel, as opposed to sampling right after a regen.

I have no great insight into why fuel dillution improved. I thought of a lab error but I think that would have effected the viscosity but the viscosity was fine.

I have a sample pump and will take a sample at 5K miles