The 5.7 Hemi is one of the most popular gasoline engines in North America and it’s pretty reliable for the most part, however, no engine is perfect and the 5.7 certainly has its flaws.
These engines are known to snap exhaust manifold bolts, and the MDS may be pretty stubborn at times, but the most notorious problem on the 5.7 Hemi is the ticking noise, dubbed – “the Hemi tick”.
Now, a slight ticking or tapping noise on any engine with hydraulic lifters is completely normal – especially for the first 10-20 seconds after startup while the engine is cold. If that is the case, then there’s probably no need to worry about it.
However, sometimes the ticking gets loud on the 5.7 Hemi and does not stop even after warming up, or worse – it just gets even louder.
To this day, there is not a lot of concrete information on why that happens, but there are a few most likely reasons behind it.
Two Reasons Why Ticking (Tapping) Can Occur on the 5.7 Hemi
There are two ways your 5.7 Hemi might develop a loud and persistent ticking noise. Diagnosing and fixing them does require decent mechanical knowledge and getting your hands dirty.
Here are the two most likely reasons behind the 5.7 “Hemi tick”.
1. Broken or Loose Exhaust Manifold Bolts
Broken or loose exhaust manifold bolts are the most common reason behind the ticking noise.
What happens is, the long exhaust manifold starts to warp due to heat cycles and pulls on the manifold suds and eventually breaks them off.
Some people replace the broken studs and drive problem-free for years, but chances are if the warping exhaust manifold broke the studs before – it will break them again at some point.
Fixing Broken Exhaust Manifold Bolts
The best way to cure the problem forever would be to buy a pair of new headers, which resists warping much better than the original exhaust manifold.
Having the broken exhaust manifold bolts fixed by a mechanic can damage your wallet by a painful 400-1000$ (depending on where you live) therefore buying a pair of new headers would make sense in the long term.
A lot of people go with the JBA or BBK Shorties, but JBA Long Tube headers offer a side benefit of giving much better performance. If you have to get new headers, you might as well get the high-performance ones (this is the perfect excuse to tell your wife, thank me later).
Now, extracting the broken bolts from the head is a major pain, but it can be done at home if you own a MIG welder. You’ll have to weld a nut to the broken bolts and then unscrew them like you normally would. The heat from welding will loosen the studs and it’s the easiest way to get them out.
In case you’re worried that weld is going to stick onto the treads – don’t. The treads are made from aluminum, which is extremely hard to weld with a MIG welder.
Here’s a great video by Mr. O from South Main Auto, showing you how to extract broken exhaust manifold bolts on the big 5.7 Hemi.
Also, make sure you don’t delay getting it fixed as the exhaust gases will leak outside and make their way inside the cab. Carbon monoxide is lethal and many people suffocate each year because of it.
2. Inadequate Lubrication of the Hydraulic Roller Lifters
This is the tricky one. If the exhaust bolts are fine and your 5.7 doesn’t have an exhaust leak, the most likely reason behind the ticking/tapping noise according to some mechanics is inadequate lubrication of the hydraulic roller lifters.
At first, it starts as a ticking noise and then it gets worse and worse until the engine starts to misfire on hard acceleration. You might even get P0300, and P0308 fault codes.
At that point, the needle bearings on the lifters start to seize and the now stuck lifters start to eat away at the camshaft lobes. And that’s why the engine starts to misfire – the camshaft lobes that have been worn no longer provide adequate valve travel.
Credit for the discovery goes to Tony from Uncle Tony’s Garage on YouTube. He goes into a lot more detail on the issue in this video:
Now, the key takeaway from the video is that due to the design choices on the 5.7 Hemi, the hydraulic lifters do not get enough lubrication at idle, and especially – extended engine idling periods, like constant stop-and-go traffic.
That theory is further reinforced by police cars being affected more by this issue, and that is because they let the engine idle for extremely long periods of time to keep the AC going.
If the camshaft on your 5.7 Hemi is toast, then be prepared for a pretty expensive repair bill of around 600-1000$ of just the labor (again, depends on where you live and other factors).
Can You Fix This Issue?
Now, camshaft failures don’t happen as often as you’d think, but they still occur to the point where it’s a known problem but not widespread enough to force anyone to come up with a real, permanent fix.
The only and best way to get the ticking noise fixed if you catch it early enough is by using high quality full synthetic motor oil, that meets the requirements of Chrysler Material Standard MS-6395 and is of the proper viscosity that’s required for your specific vehicle.
If you catch the problem early, proper engine oil will likely make the ticking noise go away in seconds.
In case you’re unsure which oil you should use in your 5.7 Hemi, then check out our article on the five best engine oils for 5.7 Hemi. All of the engine oils in the article have been known to make the tapping noise go away for some people, and they should provide better lubrication for the lifters.
How to Prevent Roller Lifter Failure in the First Place
The best thing you can do to avoid the problem is to avoid prolonged idling, because that’s when the roller lifters aren’t being lubricated properly.
Of course, nothing can be done about stop-and-go traffic but make sure you don’t leave your 5.7 Hemi idling just to keep the AC going or to just warm it up.
However, if you have to keep the engine idling, give it a few revs once in a while – this will increase the speed of the reciprocating parts of the engine and therefore will increase the amount of oil splash that lands on the roller lifters.
And besides, that is a good excuse to listen to your big 5.7 Hemi roar – because at the end of the day, it’s still a great engine.