Brad1984

I know I'm a little late to the game here but I just had this problem and thought I'd share.... I have a 2013 GMC Sierra 1500 SLE 5.3L. Bought it as second owner with (at the time 31,000 miles). Have all the service records from the previous owner. It now has about 64,000 miles. Recently (at 63,200 miles) I had the normal oil and filter change. I usually use any good full synthetic and a K&N oil filter. I decided to change it up and tried out Mobil1 Annual Protection and a Mobil1 Annual protection oil filter to see how it does. Now before I get yelled at I would never go 20,000 between oil changes like Mobil1 claims can be done with the setup. I only do 7,000 or 8,000 miles a year in this truck. Anyways, immediately after this oil change I noticed and change in my oil pressure. I was use to seeing a minimum of about 27 psi at idle and 40 psi plus at highway speeds with the oil fully hot. After this oil change I was getting 18-20 psi at idle and maybe 25 psi at highway speeds under the same conditions. I watched the gauge over the past 800 miles and it stayed about the same. I thought "well, good rule of thumb is 10 psi per 1,000 RPM." Today I got a engine check light and it was a low pressure warning. Took it to my mechanic and he crawled through it and tested the sensor and said it seemed to be working properly but to maybe replace it. He also said it could be a bad oil pump or clogged oil filter but that would be unlikely due to be a good filter and good oil. I asked him to change the oil filter and oil and we'll go from there. I bought Valvoline full synthetic and a Purolator BOSS oil filter and had him do the change.... There was a immediate change! Drove the truck on back roads and the highway for 30 miles. Speeds from 5 mph to 75 mph. Also with it in tow mode some of the way to get higher rpms. Everything is back to the way it use to be. There was no viable sludge in the oil filter or lower engine (he used a little snake camera through the drain hole to show me). He thinks the oil filter was either incredibly clogged with God knows what or the filter media was poorly made and caused the oil to bypass the media through the valve... Either way I'm happy so far. Hope this may help someone!