# Buzz or Rattle at 2500-3000 rpm



## knock01 (May 9, 2008)

Hi, newbie hb owner of a 94 pickup with a 2.4 motor.
1) Is this a belt or Chain drive for the cam.?


I just bought this clean rig, but it has a buzz, or rattle when operating the motor anytime between 2500 - 3000 rpm only.
Is this more than likely a worn out chain or guide?

I can feel this buzz/rattle when placing my hand on the valve cover, or any other part of the engine, as my wife holds the accel. at 2500rpm.

Otherwise, is runs and accellerates beautiful.


ALSO...IS THIS JOB FAIRLY STRAIGHTFORTH IF I HAVE A CYLMER TYPE MANUAL...AND DOES IT TAKE SPECIAL TOOLS, AND PULLERS TO DO THIS.
Your Advice is Appreciated.


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## rockcrusher44 (Oct 7, 2006)

Welcome Knock01. Your 2.4 motor has a timing chain and if it behaves like mine did and it needs new guides it would rattle mostly at start up and idle. You may want to check the heat sheild on your exhaust manifold. I have a 1997 HB that deveoped a rattle at low RPMs and it turned out to be the heat sheild was cracked and had worked its way loose. The guy that helped me work on it said this also happens from time to time on the one on the cat. converter. I'm sure it could be a lot of other things but this is just from my limited experiance. Good luck


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## knock01 (May 9, 2008)

*MORE CRAWLING UNDERNEATH*

Thanks, beings things are quiet while cold and at idle. I will concentrate on other areas of the truck. I used a mechanics stethiscope, and seemed to find things quite noisy in the rear support or transmission support area. 
I tested this in neutral while having someone keep the rpms at 2700.
I am relieved temporarily, that I don't have to do a cam chain change out yet.

THANK YOU FOR THE REPLY


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## pontgta (Feb 11, 2008)

I hate to bring up old threads, but I am having the same issue. In neutral, and highway, I get the buzz rattle at anything abouve 3000 rpm, so basically have to keep it under 66MPH.


Did you figure it out?


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## tomit (Jul 2, 2004)

My ride gets the same 3000+ rpm buzz. I thinks it's the timing chain. Anyway, not worth fixing, for me.

Tom


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## pontgta (Feb 11, 2008)

tomit said:


> My ride gets the same 3000+ rpm buzz. I thinks it's the timing chain. Anyway, not worth fixing, for me.
> 
> Tom


Well, I am going to have to change it then, but can not do it for a few months, so I will let you know..


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## pontgta (Feb 11, 2008)

Well i finally got around to doing the timming chain. The truck has 197k and had no issues before this.

I found the timing guides in place, but the tabs were broken. I am glad i did it because who knows how long. It would have lasted. 

Replaced timing chain with the beck arnley kit....very nice all made in Japan. And also replaced water pump and oil pump. 

So, took i for a test drive, and SUCESSS!

No more buzz, and i can go over 70mph, although i generally keep it at 65.

Thanks for all your help..


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## Shut-Trip (Oct 18, 2012)

Sounds like you figured it out. I was surfing the problem, as I too noticed a sort of buzzing.


........as I too noticed a sort of buzzing sound.
(almost like a Weed eater, for lack of a better decription).

I was thinking it was something around the radiator, or the cooling fan,
and its most noticable at higher RPM's rathter than idel speed.

In addition: This was on a 1997 Hard body Nissan, 
about 206,000 miles, automatic, 2WD, 2.4 L engine 4 Cylinder.
I bought this beast 2nd hand at about 20, 000 miles back in 2001.
and it hasnt gotten a lot of TLC, as I dont have a garage, etc.

any advice, observations from knowlegdable source is appreciated.


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## pontgta (Feb 11, 2008)

Yes, i troubleshot mine by removing all the belts and starting the vehicle, i still had the buzz. Rev your engine in neutral, and you should still hear the buzz. 

My recomendation is replace the timing chain. I was told that it should last the life of vehicle, which the chain does, but not the guides. The guides are plastic and wear.

The beck arnley kit is awsome ALL MADE IN JAPAN.

Take a look at this for a how to guide. Timing Chain replacement on KA24E - Infamous Nissan - Hardbody / Frontier Forums


Also mine is 1997 with 198k. 5sp manual king cab.


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