4.7 V8 Engine Knock

[CanadianNick]

Hello everyone. My name is nick, been a long time lurker on this board ever since I bought a Dodge Ram. I have a 2011 Dodge Ram 1500 4.7 V8 with 120 000 km. I know, I know, should have gotten a hemi, but the price was right at the time so I bought it.

Have had a couple issues since I bought it. Firstly the fan clutch was broken so the fan was on all the time. Sounded super loud all the time. Anyways got that fixed which lead my to my next and current problem. I couldn’t hear it before because the fan was so damn loud, but since I got it fixed I have noticed a knock.

The knock is heard on start up and it kind of goes away once the engine warms up but doesn’t go away fully. It just doesn’t sound as loud once the engine is warm. I have done quite a bit of research trying to figure out what it could be. I have searched this site and numerous other Dodge forums and YouTube to try and see if I can match the knock and can’t really find an answer.

The most common answers I have found is that it could be broken exHaust manifold bolts, hemi tick(which wouldn’t apply to me) lash adjusters or maybe even piston slap. So after watching a few videos and doing quite a bit of reading I was almost certainly convinced that I had some broken exhaust manifold bolts. So this weekend I went ahead and took the tires off both side and checked out the exhaust manifolds. I took the heat shield off and there were no broken bolts to be seen. Both sides looked good and no broken bolts or sings of a leak.

I’m kind of lost as where to go from here as from listening to other engines that have piston slap or lifters noise don’t sound like what I have. Again it’s a light knock that fades as the engine warms up but doesn’t fully go away. Also it can only be heard at slow speeds. Once I’m going over 40km/h I can’t hear it anymore. It also seems to be in tune with my RPMS. Sometime I get back into my driveway after a long trip and try to listen for it but I can’t really hear it. But if I put it in park and just hit the gas a little bit it’s present again. But info hit the gas hard I don’t hear it.

Sorry for the novel I’m just trying to explain it as best as I can in hopes that someone here with a lot more knowledge about these trucks can point me in the right direction. My previous vehicle was a Lexus so Trucks are like a new world to me. Thanks in advance for taking the time to read and thanks for any replies and suggestions.

 

[Nutshell]

I had a 3rd Gen 4.7. It sounded like marbles rolling around inside the engine when I started it. It did that from about 30k till I sold it at 66. Never gave me an issue and never got any quieter no matter what oil I used.

 

[jasonw]

The 2008+ 4.7L V8s are sometimes referred to as "mini Hemis." They were upgraded around that time, got a boost in HP and TQ, and gained some similarities with the Hemi (for example, dual spark plugs). I had one in a 2010 Dakota, which I later traded in for a Ram.

Mine had a slight "knock" or "tick" to it, I believe similar to what you describe. Never hurt it, had the truck for roughly 40k before I traded it in. I did have a PureONE filter collapse (internally) once, that made a much louder knock noise that was RPM dependent as the engine was starving a bit for oil. Took me a day to diagnose. First and last time I ever buy those filters. Replaced the filter and some oil, and by next morning, she was back to normal.

If you could post a video or audio file of it, that may help. It may just be "normal" for the engine, hard to tell without hearing it.

 

[CanadianNick]

Thanks for the replies guys. I will take a short video when I am done work today. Once I do, can I just attach the video here through the reply or do I need a third party host to post a video ?

 

[Kap1]

You can post it on YouTube and provide a link here. That's seems to be the easiest way

 

[Jeepwalker]

Got a 4.7 HO in our Jeep. Just turned over 200k Mi and runs great, no knocks or anything. So, these can go a ways.

The thing to determine is if the knock is engine RPM speed, or 1/2 RPM speed which would indicate it's cam related (lifters??). You might pull the valve covers off to see if everything looks right? Easy and cheap to do. One thing that can happen on these is they can spit a rocker (easy to put back on w/o disassembly). Sometimes if it's slap that happens on a return stoke only, it's hard to tell if it's full speed or 1/2 speed. Let us know what you are hearing...

 

[CanadianNick]

Ok so just a quick update. Sorry couldn’t post a video, don’t have YouTube.

Anyways long story short I took it into my mechanic to have a look/listen. He is convinced that it’s a lifter tick but said it’s not really anything to be worried about. I dunno about all that.

One thing I forgot to mention is that I did switch over to pennzoil ultra platinum synthetic and a Mobil 1 filter. I’m not sure what the previous owner had run before. I am pretty sure it was just conventional oil.

I was told to switch back to conventional oil, that there really isn’t a need for me to run synthetic since it’s had conventional for the first 100k. I might actually be doing it bad ?