AFM Lifter Failure Explained.

carnau · July 11, 2019

Ok, So we all know AFM lifters have been known to have issue and I have seen a lot of people post tricks, or preventative maintenance, or the most farfetched information I have ever seen in my life explaining why they tend to go bad. So, With that being said. I thought I would give my view on what I have been seeing and what is causing the lifters to fail.

The first thing and most important thing is… MAINTNANCE! If you fail to service your truck like you should, you will definitely have an issue. I would really recommend not using the oil life monitor and changing your oil every 4000-5000 miles. You can use Synthetic or non-synthetic oil if you follow this schedule. Oil has come so far from 10 years ago that regular oil is not that different (as far as breakdown and effectiveness) than synthetic oil.

The AFM activation and deactivation is controlled by the VLOM (valve lifter oil manifold). It has 4 solenoids that direct the flow of pressurized oil to the AFM lifter when controlled by the ECM. Now this is why changing your oil is key. The filter underneath the oil pressure sensor controls contamination from clogging AFM lifter. If the filter gets clogged from trashy oil it will cause low flow to the AFM lifter and cause it to fail. The amount of pressure the AFM lifters need to operate is 25-65 PSI of oil pressure. It needs 22 PSI of pressure to unlock the pin releasing the Lifter. This is why proper maintenance is critical.

That’s the main cause of the lifters failing, even though many other things can cause it. Modifying your ride height of the truck can cause an over activation issue. Poor fuel quality will cause the same. Larger tires causing engine strain causing over activation and the obvious… Faulty parts. Everything is man made and prone to fail at some point.

Just wanted to put my 2 cents out there. I will also link a video to the removal procedure for replacing the AFM lifter. I am working on another video for the installation now. I hope this information is informative and helps someone!!

trp34g · January 6

Very telling that you have not received any comments. I don’t think that those who trash these engines online want to admit it’s maintenance and modifications that cause the failure. No doubt bad parts exist, but there has to be more to it than “junk” design.