8.1 Oil Pressure and Filter

[BurbMan]

Last oil change I installed a Fram Ultra Guard since the Wal-Mart by me stopped carrying AC Delco filters. Local auto parts stores don't seem to carry the AC Delco filters either. Right after that I ordered some OEM PF-454 filters from Rock Auto so now I have a few on hand.

On a road trip to Chicago last week I noticed that the oil pressure was lower than normal....it was only running about 20 psi at idle and about 45 psi at 2500 RPM. I did an oil change yesterday with a little over 5k miles on the oil, and today I see the oil pressure is running about 10 psi higher, 30 psi at idle at about 55 psi at 2500 RPM with the AC Delco filter installed. This is where the oil pressure always was on this truck, so I consider this to be normal, so the oil pressure was running about 10 psi lower overall with the Fram filter.

The oil I am using is Mobil-1 5W30 Hi-Mileage formula.

I'm not sure if this is a function of having 5k miles on the filter or if the Fram filter is too restrictive vs. OEM. I never recall seeing a drop in oil pressure over the life of an oil filter. Does that mean the Fram is filtering better?

As an aside, I changed to synthetic at about 100k miles (160k on the truck now) and have noticed about 1 mpg improvement and I no longer get the infamous "piston slap" at startup...much quieter now. For the first 100k miles, I used regular dino oil with a 3k change interval, now I go 5k with synthetic.

Who makes the best oil filter these days anyway? The AC Delco's online were only $3.40 each, the Fram was $8+ at wally world, and I see they now have Bosch filters at $10+. Tempting to think that the more expensive filter is better, but as with anything else, that's more often marketing than actual quality.

I also did another Blackstone sample, and will post results when it comes back.

[BurbMan]

AH64ID wrote:
Amsoil filters are among the best at 20µ at 98.7%,
Wix is also good at 20µ at 95%.
Donaldson is 22µ at 98.7%.
PureOne are hard to beat. 20µ at 99.9% (Amsoil used to have this same rating, but it changed in 2011.. not sure if there was a standard change??)
AC Delco PF454 22µ at 99%.

Can you help me understand what these numbers mean? Is that largest micron particle size and efficiency?

[Bird_Freak]

We stopped using Fram filters years ago. We use Wix.

[AH64ID]

Amsoil filters are among the best at 20µ at 98.7%,
Wix is also good at 20µ at 95%.
Donaldson is 22µ at 98.7%.
PureOne are hard to beat. 20µ at 99.9% (Amsoil used to have this same rating, but it changed in 2011.. not sure if there was a standard change??)
AC Delco PF454 22µ at 99%.

Those are all specific to this application.


One should note that the PF1218 is larger, but MUCH less efficient. The PF1218 is rated at 35µ @ 99%, so I wouldn't run it over the PF454. The lower ratings may be AC Delco specific thou, as the Wix Cross (only one I looked at) is the same for both the 454 and 1218 cross.

[BurbMan]

weathershak wrote:
I use the PF1218 1 qt filter or a WIX alternate .

The oversized filter won't fit in a 4WD application because of the front drive shaft and transfer case...

[weathershak]

I use the PF1218 1 qt filter or a WIX alternate .

[BenK]

PureOne (Purolater), NAPG Gold and AC Delco are the only ones I use

Pressure drop is one method of gauging filtration effectiveness...but not in all
cases..

My 96 Sub's 7.4L has only had Mobil 1 5-30W it's whole life. Now at +163K of VERY
hard driving and is now showing a little pressure drop

Used to peg it at startup. Now just over the 80PSI line cold

Up to temp is is about 75PSI above 1200 RPM and 35-40PSI at idle.

Key is to know what is normal and then when it isn't feeling well...can tell
like you have noticed

The other part is that it went back up when you changed filters

I do NOT like FRAM engine oil fiters and won't use them