Cylinder deactivation

[gr8fl4porsche]

2 trucks in our small fleet both had cylinder deactivation lifters fail this month.

These lifters will end up costing me about $10-11k.

'12 GMC 6.2 - 124,000 miles - 2 lifters failed and ruined the engine. New long block required.

'14 Ram 1500 with a 5.7 Hemi 240,000 miles - 2 lifters also failed - luckily no major internal damage. Unluckily, the issue is so prevalent that the lifters are backordered - so we are converting it to non-deactivating lifters which requires an ECU hack on top of the lifters and a cam.

[1990C4S]

Major redesign by GM recently. New machines, and they are behind in production...and old customers are at the back of the line.

[Arizona_928]

The hemi have known issues on the lilter failure Grinding down the lobe off the cam.

[onewhippedpuppy]

I always found it interesting that this technology never really seemed to gain much in terms of MPG. Ford's 5.0 V8 yields similar MPG and HP in their trucks but without the additional gimmick.

[hcoles]

Do the new (2019) 5.3 and 6.2L GM truck motors have a better (better long term reliability) deactivation scheme compared to the first gen. deactivation? Or is it the same mechanism with possibly better materials?

[berettafan]

Google gm afm problems.

Set aside a lot of time to read it all.

As they’ve never acknowledged how awful the system is I don’t trust they’ve done anything to fix it.

[Tobra]

I would never consider a vehicle with this feature

[hcoles]

That's one reason I got a 2006 Tahoe. I believe that was the last year for the 5.3L without cyl. deactivation. I've been reading about the issues. There is almost a separate industry providing the parts/etc. to deactivate or remove the cyl. deactivation.

[1990C4S]

Originally Posted by hcoles

Do the new (2019) 5.3 and 6.2L GM truck motors have a better (better long term reliability) deactivation scheme compared to the first gen. deactivation? Or is it the same mechanism with possibly better materials?

I think every engine has the new design now. My recollection is that the product was redesigned and the engine management software was revised.

I have a source at GM, but he would be very suspicious if I were to call and ask all the questions I want answered...

[RKDinOKC]

It's all the EPA's fault. Removal of ZDDP from engine oil, and removal of the chemical that made the material hardness of the lifter/cam components. Lifter/cam failure was rare before those things changed. If I were building/rebuilding and replacing those components I would seriously check into cryotempering to make them as durable as possible.