Dreaded "hemi knock"

[day1glo]

I did a search and didn't find anything, so forgive me if this subject has been beaten to death here. My 07 Ram has developed a knock in the left rear side of the motor. When I looked online there is a lot of discussion about a typical knock made by 5.7 hemis after around 65000-70000 miles. Has anybody heard the most common cause of this?? mine is noticable after start-up but seems to go away after the engine is warmed up.

I don't expect to diagnose my engine in this thread, I was just curious if there is any truth to the "hemi knock" and if there is a known cause? I was going to trade in my truck, but would prefer to avoid the Hemi if this is something that I might run across again.

 

[cwhubb]

it sounds like piston slap, knocks when its cold then when its hot it expands and fits tight in the cylinder, are the new hemis stroked? I know some stroked engines that do that but dont have a clue why.

 

[67 coronet]

what weight oil are you running?mine makes a slight noise at start up but goes away almost instantly.try a good synthetic oil,possibly in a heavyer weight.

 

[Hemi Rebel]

you didn't get this from me:icon_rolleyes:



Vehicle IssueStanding Next To The Wheel Well You Can Hear A tapping Noise From The Heads. Sounds Like Valves Tapping.;Vehicle is equipped with a 5.7L engine. The noise is not a valve lifter, rod bearing or crankshaft main bearing noise. Engine oil level and oil pressure is ok. There is a ticking noise coming from around the exhaust manifold area. There are no exhaust leaks.System or ComponentClick,Knock,Pop,Snap,Tap,Tick;Customer Concern (No DTCs);Intake / Exhaust Valve,Cylinder Head,Exhaust Manifold,Fender,Wheel Well;under hood;Lower Speed / Below 25 MPH ( 40 KPH );Yes - Intermittent,Yes - ContinuouslyRecommendationThe descriptions of the noise may vary widely and may include: 1. Ticking (low amplitude) 2. Chirping 3. Whooshing 4. Belt type noise 5. Exhaust type heat crackling 6. Chuffing type piston 7. Air flow in the exhaust shell ring Generally the noise is heard at idle and is not temperature related. The sound can be heard from outside the vehicle at the L/F or R/F, however under the vehicle is preferred. We have reports that loosening the exhaust pipe to manifold connection can change the noise and this could be used to verify and possibly correcting the noise. Diagnostics to help qualify the noise: Remove the accessory drive belt to eliminate possible belt noise issues. Hoist the vehicle. Use engine ears or a stethoscope, listen at the front pipe near the manifold connection for noises. NOTE: Cold engines with a very pronounced ticking noise heard from the top end of the engine should be called in to STAR for lifter /tappet/valve spring diagnostics/repair. If you have determined that you have the above noise and it is not isolated to another mechanical source, the likely cause is excessive valve stem to guide clearance. MOPAR now has the revised exhaust valves with larger (29 microns) stems (P/N 53021551AB). Isolate the noisy valves and replace as required

 

[RustyRatRod]

All the problems we've been seein have to do with them crap *** powder metal rods. Seen some of them just break, cause knocks...all kinda stupid maladies. Why they went to them, I'll never understand. Cheaper, I reckon. But they sure are junk.

 

[RustyRatRod]

If that's the case, just sling some headers on it.

you didn't get this from me:icon_rolleyes:



Vehicle IssueStanding Next To The Wheel Well You Can Hear A tapping Noise From The Heads. Sounds Like Valves Tapping.;Vehicle is equipped with a 5.7L engine. The noise is not a valve lifter, rod bearing or crankshaft main bearing noise. Engine oil level and oil pressure is ok. There is a ticking noise coming from around the exhaust manifold area. There are no exhaust leaks.System or ComponentClick,Knock,Pop,Snap,Tap,Tick;Customer Concern (No DTCs);Intake / Exhaust Valve,Cylinder Head,Exhaust Manifold,Fender,Wheel Well;under hood;Lower Speed / Below 25 MPH ( 40 KPH );Yes - Intermittent,Yes - ContinuouslyRecommendationThe descriptions of the noise may vary widely and may include: 1. Ticking (low amplitude) 2. Chirping 3. Whooshing 4. Belt type noise 5. Exhaust type heat crackling 6. Chuffing type piston 7. Air flow in the exhaust shell ring Generally the noise is heard at idle and is not temperature related. The sound can be heard from outside the vehicle at the L/F or R/F, however under the vehicle is preferred. We have reports that loosening the exhaust pipe to manifold connection can change the noise and this could be used to verify and possibly correcting the noise. Diagnostics to help qualify the noise: Remove the accessory drive belt to eliminate possible belt noise issues. Hoist the vehicle. Use engine ears or a stethoscope, listen at the front pipe near the manifold connection for noises. NOTE: Cold engines with a very pronounced ticking noise heard from the top end of the engine should be called in to STAR for lifter /tappet/valve spring diagnostics/repair. If you have determined that you have the above noise and it is not isolated to another mechanical source, the likely cause is excessive valve stem to guide clearance. MOPAR now has the revised exhaust valves with larger (29 microns) stems (P/N 53021551AB). Isolate the noisy valves and replace as required

 

[Hemi Rebel]

If that's the case, just sling some headers on it.

its not an exhaust issue. I should have left all the other nonsense out andjust put the last sentence. sorry for any confusion.

If you have determined that you have the above noise and it is not isolated to another mechanical source, the likely cause is excessive valve stem to guide clearance. MOPAR now has the revised exhaust valves with larger (29 microns) stems (P/N 53021551AB). Isolate the noisy valves and replace as required

 

[5.7 hemi]

Just use a set of stock 6.1 hemi pushrods and your golden.

 

[day1glo]

Just use a set of stock 6.1 hemi pushrods and your golden.

I have heard this as well. Hope its that simple, i like the Truck, especially now that it is paid for! Rather keep it, but that knock annoys me. If it gets worse, maybe my wife will let swap in a whole 6.1! Thanks for all of the input guys.

 

[5.7 hemi]

The pushrods are the tick, are you sure it's a knock and not a tick?

 

[Al K]

All the problems we've been seein have to do with them crap *** powder metal rods. Seen some of them just break, cause knocks...all kinda stupid maladies. Why they went to them, I'll never understand. Cheaper, I reckon. But they sure are junk.

Saw GM do the same thing on a variety of their engines. Same results. Dumb-asses still use them,if I'm not mistaken.

 

[65DODGE]

i was told the ticking noises are the injecters.

 

[Dennis H]

My 6,000 mile 5.7 tracpac Challenger had the "tick. I run AmsOil 0-30 and my pal John drove it one day. After a few rev limiting - tire smoldering runs, the noise went away. True story, it is quiet now. The tick went away. It just wanted to be romped on.

Now I just need the hop-not kit ant the E-Force Blower.

 

[5.7 hemi]

The tick on a 5.7 is the pushrods not being long enough if memory serves. All injectors make some noise, some more than others.

 

[kb67mopar]

my truck ticks a tiny bit when warm. I don't care and it hurts nothing. Drive it, enjoy it and if it bothers you just make the exhaust louder :headbang:

 

[RustyRatRod]

Saw GM do the same thing on a variety of their engines. Same results. Dumb-asses still use them,if I'm not mistaken.

They do. Cain't be resized, usually. The arguement rages over which is better. I won't get into that, but I won't use powdered metal rods, either, and I've read a TON about them.

 

[Stumper]

My turn, my 08' Charger R/T started with the ticking noise after just picking up a few thousand miles. The ticking is noticable outside of the car, and especially underneath the car, at idle. Reving up a bit, the motor sounds great and it runs great. (Does this sound familiar?).
After repeated trips to two different Chrysler dealers and a letter to the factory all I got was the old "they all do it" line with no good explaination of why or if there was anything to be done about it. I just turned 50,000 on the car and it still does it, just the same, no better no worse. Still runs strong and doesn't burn oil or anything.
The "only" explaination I ever got that made sense to me was from Arlington Engines. The fellow there explained that the ticking noise is due to the MDS system on the 5.7L motors with automatics (the only ones to date with the MDS). He explained that the way the system works is that there are selenoids that open and close to shut off oil flow to the lifters (and of course injectors) to intermitant cylinders while the motor is under no or very light load. The sound you hear is that of partially "collapsed" lifters..
He also says that you can demonstrate it by turning off the MDS system with one of the handheld programmers.

 

[RustyRatRod]

He also says that you can demonstrate it by turning off the MDS system with one of the handheld programmers.

I wonder if it can be turned off permanently? They may tell you no, but I bet it can.

 

[Hemi Rebel]

My turn, my 08' Charger R/T started with the ticking noise after just picking up a few thousand miles. The ticking is noticable outside of the car, and especially underneath the car, at idle. Reving up a bit, the motor sounds great and it runs great. (Does this sound familiar?).
After repeated trips to two different Chrysler dealers and a letter to the factory all I got was the old "they all do it" line with no good explaination of why or if there was anything to be done about it. I just turned 50,000 on the car and it still does it, just the same, no better no worse. Still runs strong and doesn't burn oil or anything.
The "only" explaination I ever got that made sense to me was from Arlington Engines. The fellow there explained that the ticking noise is due to the MDS system on the 5.7L motors with automatics (the only ones to date with the MDS). He explained that the way the system works is that there are selenoids that open and close to shut off oil flow to the lifters (and of course injectors) to intermitant cylinders while the motor is under no or very light load. The sound you hear is that of partially "collapsed" lifters..
He also says that you can demonstrate it by turning off the MDS system with one of the handheld programmers.

non mds motors make the noise too. My 04 Rumble Bee did it and it is a non mds motor.

 

[Hemi Rebel]

I wonder if it can be turned off permanently? They may tell you no, but I bet it can.

If you have the ability to reprogram the PCM then you could, otherwise tampering with it will set a DTC and the check engine light will come on.