2008 5.3L with 263K miles - issues to expect?

Oct 16, 2003
Northern Virginia
This thread below is highly informative about AFM issues in the 5.3L GM motors, I disabled mine in the 2008 Tahoe some 60K ago and all seems fine. Oil burning stopped. It was burning 1qt/1000 miles before AFM disable via tuner.
It started clacking upon cold starts some time ago but the noise went away. I change the oil twice a year with synthetic. Seems to run fine with no issues.

Now has 263K, what to expect? Everything works thus far but I got another vehicle so think I should sell this one before something fails in it and makes it just a non-running parts car. It also has a lot of cosmetic dents and such.

In the diagram in the thread below, how do I access the filter that supposedly gets plugged up?

Oct 15, 2022
Video below shows the screen I believe you are referencing.

My 01 5.3 has 205k? and is still running pretty strong. I am more concerned about the transmission failing than the motor.
Mine also slaps on cold starts but goes away after 30 seconds or so. This is common on the 5.3.

O-ring on the pickup tube is notorious for drying up and causing low oil pressure. This requires dropping the oil pan and can be a PITA depending on your specific setup and if you have 4 wheel drive. I just throw in some AT205 at every oil change for the warm and fuzzies.

Your call on whether to sell or keep it. My line of thinking is to drive it until it gives up the ghost as it isn't worth a whole lot in the condition you describe.



$50 Site Donor 2023
Jan 14, 2011
in Az where the Deer and Antelope play
You stopped the oil consumption but the parts that fail are still in there. Conservative OCIs with synthetic and a group of AFM parts that all get along is likely why you're at 263k. Since it got this far it might go to 500k, or something might break tomorrow.

(An '01 5.3 doesn't have AFM and really isn't applicable here. The pick-up tube deal is a good tip if he wants to keep it. (y) )
Dec 19, 2013
Fort Worth, Texas
263,000 miles is good life out of a any light duty gas engine, The AFM Solenoid Filter only clogs in under/un maintained engines. I would wait for the oil pressure sensor to fail before changing the filter.

With the AFM disabled....The filter doesn't do anything besides filter the oil to the EOP Sensor, No critical parts will be deprived of oil if it were to clog, Though you will see a drop in oil pressure on the gauge.