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Discussion Starter #1
I know these Hemis have naturally noisy valvetrains, but this morning in cold weather (37 F) I noticed my 392 had a faint noise that sounded like that instrument where you slide a stick over a serrated wooden block (forgot what its called), and it kind of rose and fell in pitch and volume evenly. Maybe it's done that before but I hadn't previously noticed it. I dont know if it's bad or normal.

You can hear the sound faintly in the background in the video below:


Is this a normal sound for these engines? I haven't had any diagnostic codes appear on my screen but I still wondered.
 

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Big valves, high lift cam (compared to most street production engines), awkward pushrod angle (inherent to all modern Hemis) due to the pushrods having to reach the exhaust valve rocker shaft. As some others on this forum have found in their 392 engines, the pushrods are a little bit on the short side which allows a bit more clearance and a tapping noise. My guess why they do that, is to allow for the pushrods to expand if they get hot, as in high performance driving. But that's just a theory, I really don't know for sure.

Anyway, long story short they have a lot of mechanical noise because they are big, bad ass 6.4L high performance engines.
 

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Discussion Starter #5
Big valves, high lift cam (compared to most street production engines), awkward pushrod angle (inherent to all modern Hemis) due to the pushrods having to reach the exhaust valve rocker shaft. As some others on this forum have found in their 392 engines, the pushrods are a little bit on the short side which allows a bit more clearance and a tapping noise. My guess why they do that, is to allow for the pushrods to expand if they get hot, as in high performance driving. But that's just a theory, I really don't know for sure.

Anyway, long story short they have a lot of mechanical noise because they are big, bad ass 6.4L high performance engines.
That all makes sense. And man do I love this engine, it pulls like a mad hound down low and I can chirp the tires and step the rear end out easily under 60mph.

I'm thinking about doing some mods and a tune to it to give it a torque boost in the mid-range
 

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with headphones, I can hear the cycling sound (the valvetrain has a consistent mechanical sound, normal) that could be a water pump bearing.

With colder temperatures (sitting outside) the clearances on things will be greater until they reach operating temp - I've not experienced worn water pumps on either of my V8s over the years, but I've hear descriptions of noises that indicated water pump bearings were going bad. Probably watch that and see what develops
 

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Discussion Starter #7
with headphones, I can hear the cycling sound (the valvetrain has a consistent mechanical sound, normal) that could be a water pump bearing.

With colder temperatures (sitting outside) the clearances on things will be greater until they reach operating temp - I've not experienced worn water pumps on either of my V8s over the years, but I've hear descriptions of noises that indicated water pump bearings were going bad. Probably watch that and see what develops
Thank you, I'll keep an eye on that temp gauge and an ear open to see if it gets worse
 

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Thank you, I'll keep an eye on that temp gauge and an ear open to see if it gets worse
If you suspect the water accounts for any of the noise my advice would to inspect it, check for bearing play, leak sign, and if you spot any of these to replace the water pump and T-stat pronto.

It is simply not a good idea to continue to use the car with a bad water pump.
 

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If you suspect the water accounts for any of the noise my advice would to inspect it, check for bearing play, leak sign, and if you spot any of these to replace the water pump and T-stat pronto.

It is simply not a good idea to continue to use the car with a bad water pump.
Thanks, I will. I'm unfamiliar with water pumps, how am I supposed to check for bearing play? Just spin the cooling fan?
 

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Thank you, I'll keep an eye on that temp gauge and an ear open to see if it gets worse
If you suspect the water accounts for any of the noise my advice would to inspect it, check for bearing play, leak sign, and if you spot any of these to replace the water pump and T-stat pronto.

It is simply not a good idea to continue to use the car with a bad water pump.
Thanks, I will. I'm unfamiliar with water pumps, how am I supposed to check for bearing play? Just spin the cooling fan?
That you have to ask suggests to me you probably want to take the car in and have a professsional evaluate the car and the water pump, or least the noise that makes one suspect the water pump.

It is not possible for my to post a through description of what is involved. But I can give you while something better than say a 10,000 feet view it wil be still a veiw from some height.

The water pump is probably driven by the accessory drive system -- some cars but probably not yours can have an electric driven water pump -- so one needs to gain access to this -- with the engine off and cool enough the radiator fan can't come on on its own after the engine has been shut off -- and remove the belt noting its routing (take a pic) and direction of rotation -- so the belt can be installed just like it was before it was removed -- then the accessory drives checked by hand for any play. My limited experience is the accessory drive with any play is the "bad" drive. The power steering pump, AC compressor, alternator generally fail less often than the water pump so you have 3 accessory drives to compare to the water pump.

Also, if the water pump does have some play often this is accompanied by a leak. Anti-freeze leak is hard to miss. If it is not severe enough to drip hot (or cold) coolant on the ground as the coolant evaporates -- the water pump almost always leaks only when the engine is hot and the cooling system pressure is greatest -- after leaking just the water vapor leaves. This leaves a residue of anti-freeze. This residue can range from a nice white stain to a blob of solidified anti-freeze of (in the case of one of my cars) a nasty yellow/green blob.

'course afterwards you have to install the belt and make sure the accessory drive is restored to proper operating condition. Then if you identify a water pump (or any accessory) drive with play to arrange to get the car in for a professional's diagnosis. Replacing a perfectly good water pump is bad enough but to replace a perfectly good alternator, power steering pump, or A/C compressor is really painful (read: $$$).
 

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Thanks, I will. I'm unfamiliar with water pumps, how am I supposed to check for bearing play? Just spin the cooling fan?
they way I'd go about it - remove the serpentine belt (tensioner requires a lot of leverage to get it off the belt) check pump pulley from play back to front, spin by hand to see if there's any noise or roughness while turning it or any side to side play. A normal pump will not have any noises or play.

There's no belt driven fan on these cars - its electric.

another way is using a stethoscope (there's versions made for automotive use) to probe around components to see what noises and where they're emanating from
 

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Discussion Starter #12
Yeah, it's the water pump making the noise. I'd heard that some of them were defective on the 2015-2017 models, good thing I bought an extended warranty!
 
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