There was a post, I believe, in this thread or in another forum, about someone who diagnosed the sound coming from the front of the motor. After tear down they (not Chrysler) found the chain tensioners worn through. After replacing the chain and tensioners the sound went away. (I recall he also replaced the VCT phaser as well) I don't remember reading a follow up post, but the poster said they would repost if the repair didn't work.
As I've mentioned a CDJR technician don't me that he had resolved a number of these same issues (MDS ticking) by replacing the chain and tensioners. I think he said he had done four of them with complete success.
To your question, though, when the PCM tells the engine to go into MDS, oil pressure is RELIEVED from the four MDS cylinder lifters, which allows them to collapse as the cam rotates to lift them. Therefore the valves for those cylinders are not actuated and the normal downward force on the camshaft is reduced by 50%. What part the cam phaser might play in this I don't know. My 2010 had VCT, my 2014 has VVT. Not sure what the component differences are.
Regards,
Dusty


2014 Ram Big Horn 1500 Quad Cab 2WD, 5.7 Hemi, 8HP70, 3.92 LSD, factory dual exhaust, 20” wheels. Now at: 020143 miles.

 

I’ve been thinking that too. Perhaps a manufacturing defect in the block or in instances where the engine has suffered some other internal failure, debris obstructing those intricate little MDS oil passages. Oil system pressure issue? Dunno… just stabbing at stuff.


Cheers,


Keith

 

This has been on the Tube for a bunch or yrs. It's a Gen 1 “new Hemi” but the technology is the same in the Eagle engines:


VCT and VVT as applicable to the 09 and up Hemi engines are one and the same. It was a name game performed by Chrysler late in the 09 MY and they did a terrible job of relaying those details to the consumer. Some folks were actually out searching for VCT powered Rams late in 09 because they'd been led to believe (erroneously) that those engines produced more power than a VVT engine.

All the best,

Keith

 

Well, why I don't think it's a oil supply issue is because the symptoms go away for a very short period after the lifters and camshaft replacement. If there was a clogged oil passage to an MDS lifter, the symptom would reappear very soon, if not go away at all. And I think withy insufficient oil in the lifter the PCM would see that as a cylinder imbalance and throw a code. I know that in one case using the incorrect oil caused a Diagnostic Trouble Code (DTC).


On the other hand installing fresh lifters and camshaft may just be changing the camshaft load dynamic enough to eliminate the noise for a short period of time (fresh lifter working against a fresh cam profile might provide enough downforce to increase timing chain loading in a marginal system) . In my case, the MDS noise came back with 3000 miles and of the few other cases it came back within 2-5K miles.


Of course there are other valve train components to consider: pushrod and rocker shaft, lifter cup, weakening valve springs. (Although I have a friend whose 2013 Ram 5.7 broke an inner valve spring. Strangely, it idled rough and stalled but did not cause any noise.)


Of course, everything we've discussed is supposition. What worries me is that I have a feeling Chrysler engineering doesn't know either. They'd need a complete defective engine in order to provide competent testing. Since the various techs. I've talked to all to seem have different or no idea, I suspect the real cause isn't known yet. I'm being told there's no Star Case on record for this problem (as of January of this year).


Regards,
Dusty


2014 Ram Big Horn 1500 Quad Cab 2WD, 5.7 Hemi, 8HP70, 3.92 LSD, factory dual exhaust, 20” wheels. Now at: 020339 miles.

 

My 2010 has this issue was well. It started about a year ago, and right now she has around 67k miles on it. It only happens at idle for me. As soon as I put in any throttle input it goes away. It also seems to go away when the engine has been running for at least 10 - 15 mins. I haven't had it looked at yet. It is out of warranty, unless power train covers it, so I haven't bothered yet. That and my dealership is an hour away. I might give them a call on Tuesday and see what they say. It would be nice to have it fixed. Especially if it is going to cause issues down the road.

As for oil weights mentioned earlier, I've inadvertently tried that. A couple changes in a row, I had picked up the wrong weight. I used 10w 30 instead of 5w 30. No error codes, and everything else seemed fine. The ticking had already started previously, and the different weight had no effect on it.

2010 Ram 1500 Crew 5.7L 4x4

 

If your are not using 5w20, then you are using the wrong oil

 

Sorry, meant 5w 30.

 

Got my truck back from the dealer this time after only four days, they found that the previous dealer (Tom OBrien Greenwood Indiana) when replacing the head, broke a manifold bolt off in the head and tried drilling it out without success. Didn't get it all out but went ahead and put a new bolt in, Of course they couldn't have gotten it tightened correctly. That's where my ticking was coming from. The new dealer replaced the head and the manifold, fixed it! And it was covered under powertrain. Sounds like a new motor! Thanks a million WestGate Chrysler Plainfield Indiana !!

 

Good points and I would agree that Chrysler's engineers have drawn a blank as regards the mechanical mechanism that is causal to this issue. That was apparent in my efforts to have the problem resolved.

I suspect that at one point there may have been Star Case, which has since been quietly retired. Not enough complaints and not deemed to be a safety hazard. Just speculating...

Nevertheless, and aside from the fact that the "new Hemi" has, by design, an atrociously noisy valve train to begin with, this MDS tick/rattle/clatter etc thing is anything but normal. I find it somewhat offensive that (in my case) Chrysler instructs a technician (who's shaking his head) to tell the service writer (who's shaking his head) to inform the customer that: "all that clattering coming from your engine, that wasn't there for three yrs and 50K km, is, umm... normal." What a charade...

All the best,

Keith

 

Dusty,
There was a star case on my truck last fall for the MDS noise. On my current receipt they call it a Cair File. Possibly typo. Not sure what that is but it was referencing the Star Case I had last year.