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The unbreakable engine finally broke something

7K views 21 replies 11 participants last post by  opposite locker 
#1 ·
With all the miles, hard use, & high rpm on my 2008 4.7l, I would've expected issues a long time ago (it's a gasoline dodge, right?). But the motor has always run like a top, never leaving me stranded or even burning/leaking a drop of oil. Until yesterday...

Was passing someone on a country road, and did the usual 6-5-3 downshift and ran it up to just over 5k (once again, as usual). Well after getting back up into 6th, CEL started flashing & beeping, and the engine started making a LOUD tick on coasting & especially deceleration. Pulled over to see the idle fluctuate and engine almost die, but it kept barely catching itself. Checked oil & coolant, both of which looked fine. Luckily Dodge dealer was pretty close so I limped it over there.

Based on the noise, me & the SA think it's either a broken lifter/rocker or a busted valve spring. They will hopefully get it apart tomorrow to see what actually happened.

As reliable as this truck has been, it did need all new rear diff internals 4k miles ago, and now this. All if have to say is TGFLPTW! Thank god for the lifetime powertrain warranty...
 
#2 ·
Maybe they will give you a brand new short block! Fresh start. Lol
 
#3 ·
that warranty was a really good deal, the original owner just has to remember they have to take it in every 5 years(give or take a couple of months) from the day they bought it for an inspection or they void the warranty.
 
#4 ·
NO, this truck must keep going! Hoping for a quick fix to your issue. On a side note, is it common for you to run 5K RPM before shifting while unloaded? I'm not sure what's good or not good, but I've never had my truck over 3K RPM...
 
#5 ·
Maybe they will give you a brand new short block! Fresh start. Lol
Might not be a bad idea! I wouldn't complain. Lord knows the bottom end has been through a lot...probably as many revs as a normally driven engine with 500k.

that warranty was a really good deal, the original owner just has to remember they have to take it in every 5 years(give or take a couple of months) from the day they bought it for an inspection or they void the warranty.
Yup, but it's a painless process. Inspection is very quick, and Chrysler even sent out reminder notices.

NO, this truck must keep going! Hoping for a quick fix to your issue. On a side note, is it common for you to run 5K RPM before shifting while unloaded? I'm not sure what's good or not good, but I've never had my truck over 3K RPM...
Thanks...that's my concern is how fast they fix it, because now I'm stuck driving my tractor (2g cummins flatbed). And this truck will definitely keep going...At least until someone releases another 6mt half ton.

You've never had your truck over 3k rpm?! 5k+ rpm is a very common occurrence in my truck (loaded or unloaded), especially when downshifting into 2nd for deceleration. I'd guess it sees 5k at least 40-50 times each day.
 
#6 ·
Thanks...that's my concern is how fast they fix it, because now I'm stuck driving my tractor (2g cummins flatbed). And this truck will definitely keep going...At least until someone releases another 6mt half ton.

You've never had your truck over 3k rpm?! 5k+ rpm is a very common occurrence in my truck (loaded or unloaded), especially when downshifting into 2nd for deceleration. I'd guess it sees 5k at least 40-50 times each day.
No, I never downshift into second primarily because it is so low, but I do rev match and even then it's never over 3K. I tend to base my upshifts off of a combination of feel and the recommended MPH shifting points for the G238 found in the owner's manual, and even then it's never been over 3K RPM. But obviously you're doing something right with 270,000 miles on the odometer so far...keep up the good work! :)
 
#7 ·
Turns out the culprit was a broken rocker arm, or at least that's what my SA told me. The extent of damage isn't fully known yet, but he's thinking it might need a new cylinder head. Really curious to see how the pistons & bores look after all these miles, so will hopefully go take a look (and some pics) Monday. If all goes well, hope to have the truck back by Wednesday.
 
#8 ·
The 4.7L doesnt use "Rocker Arms" so if thats what he told you then you may want to question his experience with the 4.7L... If it was a follower that broke I would really like to see that! Those things are stamped steel. I have yet to hear of a follower braking, although anything is possible. Im willing to bet you had a lash adjuster go bad which may have caused your follower to get lose. This in turn caused your follower to fall out and become crushed by the cam lobe and could have caused damage to the valve but unlikely... I doubt your head is bad... Unless you lost a seat and that could have been the cause of the follower getting lose as well... Get some pics of the carnage! This will help keep us informed and also keep your dealership honest.

With that said, 5000 RPMs is NOTHING for a 4.7L! I used to rev mine up to 6,000RPMs every day 15-20 times a day for 150,000 miles!

If you have not reved over 3,000 RPMs then your abusing your 4.7L! Take it out for a run!!! Manually shift it at 6000RPM's 1'st 2nd & 3rd a couple times a month. It will run better because of it!

SPEED SAFE, AIR RAM
 
#9 ·
The 4.7L doesnt use "Rocker Arms" so if thats what he told you then you may want to question his experience with the 4.7L... If it was a follower that broke I would really like to see that! Those things are stamped steel. I have yet to hear of a follower braking, although anything is possible. Im willing to bet you had a lash adjuster go bad which may have caused your follower to get lose. This in turn caused your follower to fall out and become crushed by the cam lobe and could have caused damage to the valve but unlikely... I doubt your head is bad... Unless you lost a seat and that could have been the cause of the follower getting lose as well... Get some pics of the carnage! This will help keep us informed and also keep your dealership honest.
What he said was "I can't remember the exact part, but the tech said it was caused by a broken lifter or rocker or something like that." So I assumed it was a rocker since the SOHC doesn't lave lifters...isn't that correct? He's supposed to call me when they get the cylinder head off tomorrow and I'll try get some pics.

Not so worried about the dealership's "honesty." This SA has done pretty much all major services on my truck since day one, and he's always treated me well. And since it's covered under warranty, I really don't care what they replace as long as it's fixed in a timely manner. He just seemed to think a cylinder head would be needed...I'll hopefully see the reasoning behind that tomorrow.


With that said, 5000 RPMs is NOTHING for a 4.7L! I used to rev mine up to 6,000RPMs every day 15-20 times a day for 150,000 miles!

If you have not reved over 3,000 RPMs then your abusing your 4.7L! Take it out for a run!!! Manually shift it at 6000RPM's 1'st 2nd & 3rd a couple times a month. It will run better because of it!
Id have to agree on both counts. 5k is easy for these motors, but believe my rev limiter is around 5600 (have hit it several times). But it's also 100% stock to preserve the warranty. My engine never seemed to complain with high RPMs (except for occasional pinging at >5k in hot weather), and I think it is part of the reason everything's been running well for so long. Haven't even touched the original PCV valve in 270k, if you can believe that.
 
#11 ·
Ok, got the story a little more straight. What actually happened is one of the valve springs broke, causing "failure of the lifter assembly," whatever that means. Some stuff was bouncing around in there, and apparently caused enough damage to the head internals that it isn't worth trying to fix. Unfortunately I didn't get a look inside the head since I went in after service closed, so couldn't move anything around. Here are a few pics I took of my 270k mile '08 4.7...was in a rush so didn't check to see if the pics were any good til I got home







Couple notes - there appears to have been a bit of coolant seeping into the rear cylinder, as indicated by the light rust. SA said head gasket was in great shape, and suspects a minuscule crack in the cylinder head...but guess we'll never know. Also, it's tough to see in pics since head was recently removed and there was oil on everything, but the cylinder bores looked great (except the rust on rear cylinder), especially with this many miles. Also you'll notice there was carbon on the piston tops & valves, but it was actually a rather thin layer. I'm thinking not too shabby for so many miles on almost exclusively 87 octane with the occasional bottle of Techron concentrate.

Should have the truck back in the next couple days, with a brand new cylinder head on an otherwise original motor. Wonder how much longer it'll go before the other head or bottom end takes a dump
 
#13 ·
Nope...no deductible. Motor work is gratis
 
#14 ·
ok good to hear its going back together i too go over 5k often prob. every day first time ive seen inside the 08s i see the heads have a different profile on the cylinder (more round) and the pistons arent flat like the older models very interesting to see
 
#15 ·
Ya, hopefully it runs like it used to with the new cylinder head. I do suspect that it might not be long before one of the valve springs let's go in the other cylinder head. I mean...there's only so much a valve spring can take, right?

Really glad I resisted the urge on multiple occasions to plug in a tuner. That might've made this warranty deal more of a problem...

So is there any sort of "break-in" procedure for a new valve train?
 
#16 ·
As reliable as this truck has been, it did need all new rear diff internals 4k miles ago, and now this. All if have to say is TGFLPTW! Thank god for the lifetime powertrain warranty...
That started about 7 months after I bought my truck...and I wasn't eligible to "buy-in" to the program either. Good thing my truck only has 65k on it right now. The miles yours has on it encourages me; this engine should last me a while!

You've never had your truck over 3k rpm?! 5k+ rpm is a very common occurrence in my truck (loaded or unloaded), especially when downshifting into 2nd for deceleration. I'd guess it sees 5k at least 40-50 times each day.
My truck hits 6,000 rpm weekly, and 3000-4000 rpm daily, i think. I'm a little surprised your rev limit is 5600 rpm. I'm running a Superchips 91 tune, and I've seen my engine hit 6500 rpm when I drop the hammer and it does the 1-2 shift. Gotta admit that scared me the first time I saw it, but Nick (AIRRAM) said I had nothing to worry about. :D
 
#17 ·
My truck hits 6,000 rpm weekly, and 3000-4000 rpm daily, i think. I'm a little surprised your rev limit is 5600 rpm. I'm running a Superchips 91 tune, and I've seen my engine hit 6500 rpm when I drop the hammer and it does the 1-2 shift. Gotta admit that scared me the first time I saw it, but Nick (AIRRAM) said I had nothing to worry about.
Been a while since I hit the rev limiter, but pretty sure it's somewhere between 5500-5700 rpm...never been anywhere near 6k. This is of course with 100% stock ECU tuning. This is literally the very first engine issue for my truck, so yeah I'd say you've got plenty of miles left. Not so sure about the automatic tranny, but good luck!
 
#18 ·
glad its all gonna work out... that's good, even wear on that motor, glad it's bein a work horse for you..
 
#19 ·
Thanks Fred! I actually would like to speak with you on an unrelated note pertaining to the factory LSD. I'll send a PM here shortly.

So got the truck back, and it runs just like it did before the valve spring broke, albeit a bit quieter. Even though it took a little longer than promised due to parts & machine shop mix-ups, I'm rather pleased with my service advisor for doing his best to get the truck finished ASAP. Total time was about 10 days from drop off to pickup (incl 2 weekends), with most of that time waiting for parts & the machine shop.

So here's what the service tag says pretty much verbatim (with unnecessary stuff taken out) for those that are curious:

Cylinder head warp and leaks coolant into cylinder. Springs weak and broken...has misfires intermittent but cylinder 8 is a steady misfire. Trace ticking to right bank cylinder head area...need tear down and inspect. Remove valve cover and inspected, found cylinder 8 valve seat has dropped and rocker is out of place, also spring has crack...removed cylinder head and check flatness has 0.002 difference but noted that has coolant in back two cylinders as if coolant weeping into combustion chamber. Has rusty buildup on rear cylinder which was polished out. Inspected head gasket and no signs of leakage but noted has marks near combustion chamber of head as if coolant has seeped by. Recommend replace head for three concerns. Also upper chain tensioner had cracked. Replace rt cylinder head have valves ground to seats and installed new valve springs. Old springs not as tall as new springs by 0.030 springs weak...replace gaskets and transfer spark plugs from old head to new head (that made me laugh).....installed new upper chain tensioner as needed...now misfire is gone. Complete


My only concern now is if all 4 valve springs were weak/shorter, then I imagine the left bank springs probably look the same. Doesn't make too much difference to me if those are replaced now or at a later if/when they break, but it seems like it might be prudent to avoid a costlier warranty repair at a later date. I'll ask my SA about it, but I'm thinking most warranties won't fix anything till it's broke. Either way, thrilled to have my truck back! Put over 1000 bumpy & loud miles on the flatbed in the last 10 days...
 
#20 ·
Hit rev limiter intentionally today...right about 5750-5800 rpm as indicated in tach
 
#21 ·
If you have the means and the time, by all means, replace the springs on the other head. I know you have the warranty, but it wont take you ten days and you wouldn't have to worry about it crappy out at some in opportune time . These 4.7s are way underrated, not only do they like the revs, they like to work. If they ever offer the half ton diesel w/ a stick (we both know that aint happening...), mines getting sold, until then though, it tows 6500 lbs worth of car and trailer just fine.
 
#22 ·
If you have the means and the time, by all means, replace the springs on the other head. I know you have the warranty, but it wont take you ten days and you wouldn't have to worry about it crappy out at some in opportune time .
True, but I don't really have the time or means to do it. Engine still runs great so I'll just leave it alone and let the warranty take care of any issues that arise. Also engine now has it's first oil leak ever...appears to be coming from the bottom of timing cover. Probably bc dealer didn't seal things up properly so I'll be taking it back in next week.

These 4.7s are way underrated, not only do they like the revs, they like to work. If they ever offer the half ton diesel w/ a stick (we both know that aint happening...), mines getting sold, until then though, it tows 6500 lbs worth of car and trailer just fine.
I don't think the engine is so much underrated as it is under tuned. Gains are huge from just a tuner, though I've resisted bc of warranty. The tow ratings are lower on the 6spd purely because of the clutch and the transmission's lack of a granny gear. Same thing happened on 6spd SRT10's... Chrysler didn't want a bunch of clutch warranty claims. Agreed on all other points.
 
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