Bent Rod 5.3 - Diagnostic Red (2023)

Illinois

ralf

Did you replace the tappet guide and check the tappet bore for abnormal wear?

Kansas

Troy

The lifter guide has been replaced with a new GM guide. Yes, the jack hole has been checked.

California

justin

I would like to know about the rocker arm itself, there are needle bearings in there, perhaps they should be inspected more closely, especially if you take the valve and spring apart to inspect

West Virginia

Guillermo

Did you inspect the camshaft? The lifter usually destroys the nock by hammering.

Illinois

ralf

I "assumed" they actually checked the rocker and camera. If the roller bearing can move to the side and "tilt" so to speak it can bend a rod which is why I asked if they replaced the guide.

Kansas

Troy

Camshaft checked first but you might want to check everything again as I must be missing something.

California

maximum

check cam wear I know that many times the cam lobe wears out and the AFM lift oil passages become blocked. The only thing that moves the pushrod is the jack.

Louisiana

cris

youtu​.​be/1m6z1FQeHVY The other day I saw a very good video that explains this problem. It might not be your issue, but it makes sense.

Kansas

Troy

very interesting theory. I can check more closely. Thank you for writing

Texas

vale

Hi Troy, the heads need to be removed and the guides replaced with valves. Typically, valve stems rub against each other and have repeated bent pushrod issues. Rockers also often fail, but as I recall they have roller levers. It would be good to carefully inspect the camshaft on these AFM engines, they are bad for cam wear due to case hardening. Depending on mileage...

Florida

winner

Do you have a way to test the injectors?

Kansas

TroyUpdate

Thanks to everyone who responded. We ordered the pushrods from Crazed Performance. (Reference video posted by Chris Chandler). I installed this pushrod. He came out and did a WOT acceleration. Didn't bend the pushrod. He cut the pin inside the afm riser. Folding lift. Today I took my butt off. Cam looks perfect. The cat hole looks perfect. Elevator guide and elevator replaced...

Kansas

Troydelay

We had new valves, new guides and new springs installed in the head. Same mistake. I'll update the post when I find out. Thank you all.

Arizona

Sam

Did you discover anything about this post? I'm dealing with exactly the same problem. I replaced all the jacks and a new pushrod on #1. #6. I took it for a test ride and felt a real thud when I saw it. It sounded like a bang. I changed injectors on bank 2, same thing, then I heard the noise on WOT and then boom. The ticking came back and the AFM lifter completely dissipated at #7. pushrod…

Kansas

Troy

Well, we fixed ours. I think I forgot to update this. But the problem is, I'm not sure what solved it. The customer opted for an extinguishing kit. So we installed the kit that completely eliminated the AFM system. New camshaft, all new non-AFM lifters and a solid valley plate that obstructed the oil ports. And to cover our base we put a new pinion (vvt). The collection is fixed. I didn't see how he...

Illinois

ralf

LOL I made a ton of them. Even turning off the DOD on the ECU doesn't solve the problem forever. It appears to be a flawed design at first. Finally everyone gets the GM kit to convert.

Texas

vale

Hi Sam, I'm going to chime in here and say to remove the AFM and convert the engine back to a traditional lift and cam design. In my opinion, these AFM systems just don't stand the test of time and mileage. I've converted a few over the past few years and haven't had any problems other than one happy customer who hasn't returned for the same issue. It's not that I don't like job security, but if there is...

Arizona

Sam

Finally, delete is what we originally wanted to do. We know it would have fixed the truck and we made a lot of eliminations. I know the truck would be on the road right now if the customer had chosen that way. Now we will do the deletion and the customer will have to pay for it. Getting GM to compensate AFM lifters. I really want to know why these new engines flex pushrods. No…

Texas

vale

Hi Sam, I'm told that AFM kicks in at the wrong time. It should end in low compression, but if it kicks in at the end of TDC during a fire event, it will flex the pushrods. It could be pure computer time turn-on time.

Kansas

Troy

Interesting. ECM shouldn't even think about activating AFM in WOT, right? So pushrods usually flex.

Illinois

ralf

It deactivates at 3200 RPM or the TPS must be below 50% for DoD to activate at least this 15th model year. All must be together, but may vary slightly from year to year.

Arizona

Sam

I have a feeling what's going on here is probably oil slipping somewhere and shouldn't be causing these lifters to spring into action at the wrong time.

Kansas

Troy

Yes, that sounds logical. I'm curious if VLOM might be an issue. I tried testing my air and it looked good, but who knows.

Kentucky

tailor

Has this already been resolved? I have a 2015 Silverado in the shop that does the exact same thing on the 7 cylinder intake side.

Kansas

Troy

We carry out a complete cleaning. The AFM system has been completely erased. This includes replacing the cam and installing regular lifts. I fix it. This is a big problem with these engines. I keep hearing this happen. Does it seem like deleting is the only permanent solution?

Kansas

Troyresolution

We ended up eliminating the AFM system, which involved replacing the camshaft and installing non-AFM lifts. That did it.

Kentucky

tailor

That's what I advise we do next. We've already taken his head off twice and he keeps bending rams and breaking jacks no matter what we try.

Texas

vale

Hi Taylor, The best thing to do with any 5.3 AFM engine is to get rid of the broken system and components and go back to traditional parts. The standard 5.3 engines are very reliable without any glitches.

Kansas

Troy

I would really like to know why they do this. But you seem like the best course of action.

Texas

vale

Hi Troy, as far as I can tell the tappets tend to lag when activated and the pushrod slides out of its seat on the tappet and into the tappet side cylinder or out of the rocker arm (excessive valve clearance). Since the injector fires almost simultaneously, enough fuel enters. A combustion event occurs and loads the valve and elevator before it fully activates. I…