SilverStallion05

Hello everyone. For a few weeks now, I have heard a short rattle upon acceleration every now and then. I got out of my car the other day while it was running, and head a ticking sound. I found out it was my tensioner. I have attached a video for you to see.

I learn cars as I go, so is this my culprit for the acceleration rattle? What's causing it? A failing belt, tensioner, or timing chain? Would just replacing the tensioner take care of it? I hope, as that's the cheapest part. Haha.

Thanks everyone!

Z28KLR

You need to get an automotive stethoscope and probe the front cover. But yeah from a video over the internet it kinda sounds like it could be.

How is it at cold startup? Usually that's where it starts, a while before it's evident elsewhere when running.

Z28KLR

If you confirm it to be chain rattle, have fun. Passenger side chain is located in the rear of the engine, so that means the whole things gotta come out. You will need a new timing set, chains/guides tensioners. HIGHLY recommend doing both sides of the engine, this is not something to cut corners on. You also need to remove the oil pan and see if any plastic from the guides is in there. That stuff can cause obstruction to the pickup tube and that's bad too.

08'MustangDude

Easy to confirm tensioner or not; 1, remove the serpentine belt, and run the motor for the same seconds.
2, pull on it when it's idling, but of course, be careful. Had a jeep liberty that was chattering at the tensioner.
SO, I put a ratchet on it like I was going to remove the belt, and moved it in the tighter direction, and it stopped.
So, it was the tensioner...

SilverStallion05

Looks like I'll try the easiest route first and try just tightening it. The timing chain sounds expensive... 😕

08'MustangDude

Timing chains, plural, and guides, plural. You'd never do just one bank... If it's gonna come
apart, then you do it all.

Yeah, there is a video out there that shows how the guides break, get stuck in the head, and
the slapping of the chains. Makes you wonder how domestic cars still sell, when you have
Japanese made engines running forever. American designed motors just suck, for the
most part. I know the V6 is a German motor, but still in a domestic car, so for some
reason, they fail because of bad design or material.

Like the Neon, used a Mitsubishi motor (A588 version), yet they failed in the Chrysler, but not the
Avenger or Eclipse (420A version). All because the head went on 180 degrees opposite on
the Dodge or Mitsubishi, so they didn't have the head gasket failure. Also, the reason was
the one corner bolt hole in the block wasn't deep enough for the head bolt. SO, it would
bottom out before clamping... Drilling it deeper and tapping meant using one bolt that was
one over in size, and was the way to repair it from the start... They decided to double up on the
gaskets first... They tried shorter bolts, they broke... They all leaked oil, and for some reason
never made the recall list, yet were allowed to pollute the streets with oil, and here we have a
diesel scandal, and VW gets smashed...

Design flaws, bad material and workmanship should all have 120,000 mile warranties,
and is what VW does. When they find a part has flaws, they extend the warranty on
that part for 120,000 miles. Can't be forever....

SilverStallion05

My mechanic, without seeing the car in person, said a bad bearing could cause it too... This is sounding really expensive. I really hope the $30 tensioner just took a ****.

Z28KLR

Yeah, but that tensioner isn't easy to get to. And you don't replace JUST the tensioner.... You also MUST replace the chain guides and chains. Or find a used engine, a lot of people in your shoes do that as well. 4.0's in decent condition are not hard to come by.

SilverStallion05

I forgot to answer your question about the cold startup. It fires right up, and there are no driveability issues. Just the rattle.

I took it to my guy to look at, and he said to turn the AC on to put more stress on the belt, and the tensioner went crazy. He recommended starting with that.

I also don't know if we're talking about the same thing. I'm referring to the serpentine belt tensioner which you can see in the video, and it's one bolt which is very easy to get to. I'm not talking about anything attached to the timing chains. Which, if I did need to get replaced would cost me about $3200. My local shop that I talked to said I would know if it was the timing chains, because I would feel it. My car drives like normal. My guy and that shop said belt tensioner failure is more or less common. My car has 156,000+ miles on it. She's getting.

I'm going to order a new one for about $30, and see if that makes the problem go away.

08'MustangDude

Yes, I also meant the belt tensioner pulley... There us a bearing in that too, they
can go bad. As I said, when I pulled mine tighter, the noise went away on the
Jeep I had, so I knew it was the tensioner. ALSO, since you are going to replace
it, start the motor without the belt on, it will be safe to run for 30 seconds, if there
is no noise, again, you know you got the right culprit. IF it still makes that
noise, well, then you can take the belt tensioner back...