In today’s edition of “NAME THAT NOISE”…

In today’s edition of “NAME THAT NOISE" we have a a 2007 Jeep Grand Cherokee Limited with a 5.7L Hemi with MDS and 162k miles:

Contestants, here your clue:

The sound was recorded after approx 2 minutes of running, folowing a 10 minute shut down after it was moved from the driveway to the back yard portable garage. Prior to that had been parked since Friday evening.

Ready? Name that noise (pay no attention to the old guy behind the camera):

Lifter?

Wouldn't mind a broader survey of camera location relative to each bank etc...

Mostly it doesn't call out to me viscerally in terms of tone, so I'm going with likeliest thing to have just decided to make racket because a small piece of 162k-mile-goo plugged a small orifice.

I notice that you were paying a lot of attention to the pan, but compounding my leaning toward lifter, I get about five and a half hertz, or 330 knocks per minute, making it every other revolution at a low idle; I have it in my head that if it were bottom end, you'd probably hear it on every revolution under such light load?

I was also thinking lifter noise, bottom-end noise should happen at least once per revolution.

Agreed, it seemed to be most audible near the pan. The stethoscope picks it up loudest from the pan and the valve covers. 

The sound showed little to no change when unplugging coils one at a time, reducing chance of lower end or wrist pin. 

Now the big question is if it's worth fixing, or cut my losses and trade it in on something with a warranty.

Any misfires with it?  The mds lifters can twist in the bore & wipe out the cam, this sends a large amount of metal through the engine that can cause other damage.

In reply to Caperix :

No misfire codes, overall it runs smooth. Mainly just a noise for now. 

Variable cam timing device?  Is sounds like the Vanos unit in my kids BMW, I'm actively ignoring the sound.   

No VVT in the Hemi for Jeep in 2007.

I'm not sure if it's in my mind, or real, but the noise seems more noticeable since the last oil change. 

I ended up having valvoline change the oil about 1500 miles ago, using their synthetic blend and filter. I'm wondering if their filter is allowing more drain back when shut off, or something else. 

I need to drive it to NYC tomorrow, so I'm going to change the oil again with Mobile 1 and a wix filter today. I'm also going to add BG MOA as a stretch to see if that can help if it's a sticking lifter. 

I did some searching and it appears I need to pull the head to replace a lifter, so that's not happening anytime soon. Even using RA prices it would be a $600+ repair if I just replace all the lifters and approaches $1500 at the high end if I also replace the cam+bearings, timing set, and oil pump while in there. Neither of those include any head work, which seems likely to be required for aluminum heads at >160k miles. 

When my OM642 came apart with an obliterated rod bearing, it made a heavy tick and the sound was at half engine speed.  If the oil and filter are clean, then it's probably not that, but apparently half-engine speed can also mean bottom end...

In reply to wae :

I'm hoping it's just noise, and not something that's going to become catastrophic in the near future. 

I'm leaning towards lifter, and I have noticed the noise changes under light throttle when cruising along at 40 mph on flat roads. 

I'm assuming it's the MDS kicking in and out causing lifter noise to change, but it could be the changing load on the bottom end as it switches from active cylinder to being an "air spring"

In reply to Jesse Ransom :

Thank you for providing the frequency. I was wondering about frequency of the noise and didn't have a good way to determine it other than counting with a watch. 

Do you have an app you used for it?

In reply to No Time :

I used phyphox; I haven't played with it a ton yet and actually didn't manage to get it straight from the audio (which I think it should be able to do) and ended up getting it from the accelerometer by tapping the phone with my finger to the rhythm of the audio). It does both raw readings and analysis of a bunch of the phone's sensors.

 I'm actually having a little trouble repeating it just now, though it seemed I was getting a pretty solid reading at the time.

I originally got the app hoping to track down a chassis vibration in my truck. Maybe I'll have another stab at that today.

In reply to Jesse Ransom :

Thank you, I'll have to check that out. 

Seems like it could transform a phone into a high tech sirometer. 

So the Jeep made it to NYC and back without issue. Average economy was 14.7 mpg, and the noise is still present.

I was watching a YT video about the Hemi lifter issues and the host said the 2005-2008 Hemi engines didn't suffer lifter failures like the newer engines, but did suffer from valve seats dropping. 
 

That got me thinking....

During the street survival course my son did, the water pump was leaking and it got run hot during the course of the day. We kept adding water, but it did boil over some. 

I wonder if running hot enabled a valve seat to start moving? If it moved some, but not all the way free, it would create clearance in that valve when closed causing the noise. 

I'm thinking that could be easy to check by pulling the valve covers and checking for valve lash on each cylinder when the valves are closed. 
 

Is this a stretch, and just a waste of my time? Is there and easier way to check?

Thanks!

err.....

Every Hemi I have heard making this noise had a lifter that was eating the camshaft and vice versa.  The rollers on the lifter die and allow the yoke to hit the camshaft, or the cam lobe gets badly pitted and takes out the roller (chicken or egg?)... yank heads, replace cam and lifters.

Reman engines are cheaper than used.

In reply to Pete. (l33t FS) :

I was trying to be optimistic, and hoping it was something slightly less catastrophic than the seized roller.  

I didn't see any glitter in the oil, but haven't opened the filter to look.  I'll have to do that next. 

I need to figure out how much time and money I want to spend on a 17yo vehicle with 162k miles on it. 

I called a local machine shop to get a ballpark price on getting the head freshened up.  I'd hate to fix the cam and then have it drop a valve seat or have a head gasket let go  

They said approx $600/head with new springs seals and machining, so $1200 for the pair. It's been more than 15 years since I've had any cylinder heads reworked, but that more than remaned heads. 

It's looking more like time to trade in the Jeep while it still runs well (even though it's making noise).

I went and test drove a Forte GT manual today and really liked it, but they only offered $800 in trade for the Jeep 😳, so I walked away. 

This evening it got more complex, since my BIL is planning to give us my FIL's 2009 MINI that he got after my FIL passed away. Its only got 20k miles on it (NYC miles), and has never been driven in winter. So its a great summer car, but I wouldn't want to drive it in the winter due to sentimental reasons. 

So I still need to figure out what to do with the Jeep. I could probably sell it for $2500-3000 and pay off the rest, and tell myself the just a lifter tick and nothing serious (which might be true). I'm just struggling with feeling like I might be taking advantage of someone selling it on marketplace  

Then find something newer and more efficient for my son, and take the truck back. The truck will need some work to make it something to daily in the winter and truck stuff in the summer, but nothing requiring major engine work.