Ran a second ad in our local shopper to follow up on the oil filters plugging up. Will paste it here.
A follow up on the problem with GM pickups plugging the oil filter and losing oil pressure. When last we spoke I threw AC Delco under the bus blaming their PF48E filter for the problem. Since then I have heard from other shops reporting they too have seen the problem, and not just with the PF 48E but with Wix and other brands.
Lo and behold a couple weeks ago we had a 2009 5.3 Silverado with 168K on the odometer in with low oil pressure. Would go up rather slow then after a couple of blocks drop to zero. Motor sounded great. A look at the oil change sticker showed 7000 miles on a change with Dexos full synthetic oil, and, a Wix filter.
Changing the oil and filter resolved the problem, pulling the filter apart I found the same light carbon particles in the folds of the filter media. Hmmmm.
Doing some research turned up GM bulletin #PIP5276D. Now GM bulletins are infamous, for what they do not tell you.
Under condition/concern. “A concern of a PO521 setting after an oil change and or low oil pressure indicated on the instrument panel.
Now a note from me, Code P0521 indicates the trucks computer saw a oil pressure reading it does not expect, or like. I looked up the parameters which are used to set this code only to find they were nonsensical, or more accurately, obviously wrong. I am quite sure though that when your trucks computer sees a reading it does not like it sends a signal to the instrument cluster telling the gauge to show zero. This is to get your attention. When you shut the truck off and restart it the process repeats with the gauge telling the true reading until the code again sets dropping the gauge back to zero.
Recommendations/Instructions: “ If you are working on a Gen 4 V8 that is setting a DTC P0521 and or low oil pressure indicated on the instrument panel in cold or hot weather and the engine is currently equipped with a PF48E oil filter, replace with UPF48R oil filter if one is available.”
“NOTE: Only use the UPF48R oil filter if the Gen4 V8 is setting a DTC P0521”
And that is it. No explanation of why the PF48E is problematic, no mention of a root problem. And why in the world would you use the PF48E after reading the bulletin regardless if your truck has lost oil pressure or not?
I found the UPF48R filter is a premium filter which uses a synthetic filter media and a different relief setting on the internal bypass valve. I see no good reason to use the older PF48E on any GM V8.
As for the carbon particles caught in the filter media pleats? Seems this engine cokes up internally a situation made worse with extended oil changes.
In summary, these motors are equipped with a small filter which is prone to plugging up, of the filters used the Delco PF 48 E due to its construction, filter media used and higher bypass pressure is the most likely to give a problem. Extended oil changes compound the issue by coking/sludging the engine We recommend not extending the oil changes, using the premium oil filter along with a Dexos approved full synthetic motor oil.
