Jeep Commander Forum banner
1 - 12 of 12 Posts

·
Administrator
Joined
·
16,152 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter · #3 · (Edited)
Well thanks for the reply but I've seen that post and it isn't the hemi tick and it definitely isn't an exhaust leak. My sister in law has the same exact car (color and all) and I can hear the "hemi tick" on hers and it's completely different. I will say that before the lifters I did have the "hemi tick" noise so maybe 6.1 lifters would solve a lot of other hemi enthusiasts issues.

It seems as if it comes from the bottom end of the motor and that's aboutt all I can tells ya.
 

·
Registered
Joined
·
389 Posts
I was going to think exhaust related as well... are you 100% sure they ruled out the exhaust?
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #5 · (Edited)
Well, when i had the car lifted and could trace the issue by sound it was certainly coming from up where the exhaust manifolds would be. . (before the cat converter inline) and they put on new exhaust manifolds and gaskets so i'm not sure what else that would be??????

THEY (chrysler) completely ruled out exhaust. When i'm driving it sounds almost identical to and exhaust manifold leaking but they tell me for sure it's engine noise. Who knows though. That is coming from the dealership that told me "the abnormal noise that your hearing is normal" and "I guess you're just going to have to live with it". Go figure
 

·
Registered
Joined
·
3,037 Posts
I was going to suggest a spun bearing was a possibility.

Timing Chain? Yes, I know the 5.7L is cam in block, but the Hemi has to raise the Cam position in the block to better address the insanely tortured valve train, which results in a longer timing chain. As well, it appears the 5.7L has tensioners for the timing chain, which means the chain has physical contact with additional items (i.e. more chances to create noise).

Sorry, I did NOT listen to the videos, only other source of an rpm related tic/knock in the lower half of the motor that I can think of is, Piston Skirt Slap. Some engine designs the pistons is squashed down in height with piston rings closer together and shorter piston skirts. This makes the piston able to rock in the cylinder at greater angles and that only increases as the smaller skirts start to wear down. So the piston tilting/rocking in the cylinder can create a knock noise. And it is typically worse when cold, and then less as the motor warms up (piston expands from temp).

I have no idea how common timing chain noise is on the 5.7L Hemi, I do know that it does happen on at least domestic motors with timing chaings for OHC and it is often the tensioner that goes bad and creates the noise.

I have no idea how common spun bearings are on the 5.7L Hemi, I do know that I see posts about them for other motors and it surprises me cause that is something I never expereinced my whole life. (And they always seem to be an oil problem before its experienced, bad/old/low oil, some sort of oil pressure problem, even people using the wrong oil viscosity than is in the O.M.)

I have no idea how common piston skirt slap is for the 5.7L Hemi, I do know I have seen posts for it for other motors and it surprised me how common it is in other motors. It seems to be motors that have been driven hard and NOT well taken care of, i.e. worn faster.

On a side note, boring and stroking motors, the only way to do this is too make the cylinder walls thinner and shortening the pistons the additional distance it pushed up toward the head and pulled down toward the crank. So its NOT hard to take boring and stroking a motor too far and result in such ridiculously short pistons and thin cylinder walls that the motors wear out in no time. Saw some posts, even on this forum, where people were so excited about the bore&stroke kits for 5.7L (348cu in) Hemi's that made them into 426 cu in Hemi's. Yet, you could find some really experienced engine builders stating, these kits are insane and you can expect your motor to be totally worn out, past another rebuild, after 50k miles. Just something to think about with boring and stroking, NOT that a mild bore and stroke is a bad thing.
 

·
Registered
Joined
·
3,037 Posts
Is it still under warranty?

I guess you could take an oil sample and have it analyzed, if you had a spun bearing there would be lots of metal in the oil and an analsis would tell you that. Of course, you've said you've this a long time, so its always possible after years for all the metal to rub away and may oil changes, the metal isn't there anymore. So, just because an oil analysis comes back as no or normal level of bearing metals (most bearings have mutliple layers of copper, lead, zinc or some sort of alloys of those metals) in the oil, I wouldn't rule out a spun bearing, if it comes back with a lot of metal in the oil, then a spun bearing is a good possibility.

Damn shame that Chrysler/Jeep (as well as just about all the manufacturers) no longer put oil pressure gauges in their vehicles anymore. If you had noticed a drop in oil pressure before/after this started for the same conditions, that would be a good clue of a spun bearing.

If you had piston skirt slap, I'm guessing you would get back an oil analysis with lots of piston material in the oil (I think the Hemi has aluminum pistons, I could be wrong and they could be steel). You can do a compression check as well, if any of the cylinders fail the compression check, that could be a cracked rings or screwed up piston, like skirt slap would do to it.

Hate to say it, but to tell for sure, you're going to have to drop the oil pan and pull each bearing and check them.

Sadly, if it is a spun rod bearing, or even crank bearing, just replacing the bearing is likely just going to have it spin again. When a bearing spins, it usually damages the crank surface as well, if you're lucky you might be able to spot it and blend it down, but even that doesn't always fix the problem. Usually, what I see people recommend for a spun bearing is an entire crankshaft replacement. That will require to pull the trans as well as a lot of other stuff on top of the pan.
 

·
Registered
Joined
·
3,037 Posts
Never had oil analysis done on my own vehicles. I was a helicopter pilot in the Marines and we had the oil from all our engines/transmissions analyzed (by labs on the base) and they would come back with reports. Most were normal, but every once in a while you'd get one with a red flag, describing metals or contaminants in the oil and their likely causes. So you'd get a clue that one of the bearings in a trans was starting to fail, or a gear face was starting to strip, or the engine wasn't running right because the oil had an acid in it that came from exhaust leaking past a seal, etc, etc.

The AMSOIL fanatics brag about using oil analysis. Google it, there are labs that will send you a kit for a fee, with instructions and you mail them back a sample and they will send you report.

That is the only way I would use motor oil for a whole year, 25k miles, if I did oil samples and could get a report back warning me if the oil had become contaminated and I needed to change it. I have no doubt a high quality oil like AMSOIL could protect a motor for 25k miles or more, but if something happened to contaminate that oil, which the chances of that increase the longer you leave the oil in there, it might fail in its job, thus you need the test to tell you the oil is still good.

(I'm joking for any AMSOIL advocates out there, I agree its great oil, more teasing that some are just fanatics about it).
 

·
Registered
Joined
·
338 Posts
Have you tried listening with a stethoscope? This is an excellent way to lock in where engine noise is coming from. If you don't have one about 30 inches of 1/4 inch tubing will work quite well with one end in your ear and the other being placed at different locations on the engine.

I would run it up and down the valve covers, heads, exhaust manifold ports.... you get the idea. You will know when you find the problem, it will be quite easy to isolate the noise this way.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #11 ·
I was just looking at a stethoscope online for $10 @ AutoZone today and I thought to myself "ya that probably doesn't work". Lol thanks for the advice. That's what I'm trying tomorrow.
 
1 - 12 of 12 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top