p0521 - simple question i think

[Bleepster]

So, we purchased a 2011 Silverado 1500 LT with 62k on the dial in August.  I am ready for my first oil change based on the windshield sticker (actually 500 miles over)  the engine light came on last Friday while wife was driving.  checked the codes and it was the p0521.  i checked the oil and i was a quart low.  I added a quart of 5w-30, and reset the check engine light.  it came on again last night.  I reset the light.  I drove the truck this morning at highway speeds (60mph) and the oil pressure was steady (35-38 psi) at highway speeds.  Once i got into town and stopped at traffic lights it would drop to 22-25 psi and the needle would bounce a few PSI.

 

I am getting the oil changed today at the dealership.  if the p0521 come back after oil change, is it really that big of a deal?  seeing how per my pressure gauge my pressures are fine?

[sefiroxx]

May try changing the oil pressure sensor

Also, there is a filter/screen located below the sensor. This may have accumulated stuff. $6 part. Search for oil sensor screen.

[diyer2]

It's not as big a deal as letting it get a quart low on oil IMO.

I would still check the filter screen underneath the oil pressure sensor as mentioned.

 

[Bleepster]

THANKS - I know of the sensor and the screen.  the question was "what to trust?"  the CEL (not the oil light) or trust the gauge

[diyer2]

The best way to check would be to hook up a mechanical oil pressure gauge.

 

[Bleepster]

I'll have to invest in one.  something I need to add to the tool box - lol

 

thanks 

 

i'll keep you all posted.

[newdude]

Couple of commons on these.  Bad sensor and plugged sensor screen, also oil filter.  GM calls for the ACDelco PF-48E.  You can use the UPF-48R, or Mobil 1 filter (same as the UPF-48R). 

 

Quote

 

#PIP5276F: SES Lamp P0521 Setting After An Oil Change And Or Low Oil Pressure Indicated On The Instrument Panel - (Mar 1, 2016)

Condition/Concern

Some customers may complain of a SES light or low oil pressure indicated on the instrument panel cluster with DTC P0521 stored.  In some cases, this may have started shortly after an oil change.

Recommendation/Instructions

If you are working on a Gen4 V8 that is setting a DTC P0521 and/or has low oil pressure indicated on the instrument panel in cold or hot weather and the engine is currently equipped with a PF48E oil filter, determine if the engine has been properly repaired and cleaned following the procedure used in the latest version of bulletin 10-06-01-008.

If not, please update the engine with the components outlined in the bulletin.

 

If it has been properly repaired and cleaned, inspect the left rocker cover (square baffle) and verify that the baffles can hold water and do not leak.

 

If any leaks are found, clean and seal the edge of the baffle with RTV if possible or replace the valve cover.

 

Thoroughly clean and dry the valve cover before installation and/or resealing.

 

Change the engine oil and replace the oil filter using a PF48E type filter.

 

 

If you do an oil pressure test, do it at the filter with the proper adapter, but also at the top of the engine.  Sensor is at the top, back of the VLOM assembly, so its reading pressure at that point in the engine. 

[Bleepster]

thanks for that additional information.  the oil is changed and I reset the CEL.  So far so good - have about 1.5 hours of drive time.  Oil pressure per the gauge is close to 40 at 1200 rpms, and 30-ish at idle.

 

I need to double check what filter they used.  its AC-delco i'm sure.   i'll look at the receipt later.

 

i'll keep everyone posted.

 

thanks again

[swathdiver]

Might've just been a defective filter.

[Bleepster]

its been over a week since oil change and so far so good.  I suspect I can remedy this in the future by making sure i check oil level weekly, and keep current with oil changes.  i was 500 miles over the sticker on the windshield, not that that matters.

 

[Hillwood]

The best way to check would be to hook up a mechanical oil pressure gauge.
 
[emoji4]

To be accurate you need to check the pressure at the filter and at the sender, they should be within a few pounds of each other..
Change the sender and the filter under it first like the other people said..

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