Whats this knocking sound?

[zeke1985]

1995 Nissan ALtima. 204,000 miles. Always happens at start up, does dissipate slightly when warm, but is a very noticeable when the car de accelerates down to about 1200 rpms. Thanks!

http://www.youtube.com/watch?v=QanMjnGYf60&feature=youtu.be

 

[aquariuscsm]

What oil are you using?

 

[zeke1985]

QS Defy 5w30, with P1 filter. But its done this with Pennzoil and other filters as well.

 

[tinmanSC]

Idler pulley and a valve adjustment?

 

[aquariuscsm]

Wonder if Pennzoil 10W30 would help? I can`t really hear the noise in the video,but my friend who has a 98 Altima with a lil over 300,000 on it got lifter tick with GTX 5W30 (that the dealer put in) and went away when I changed it back to Pennzoil 10W30.

 

[Warstud]

The noise I heard doesn't sound like it's the motor. I'm guessing one of the pullys.

 

[bullwinkle]

I'm hearing several things in that video-lifters, and sounds like possible timing chain noises? Agree that thicker would be a good move-T5 10W30, or maybe even a 15W40 HDEO would possibly help.

 

[Rick in PA]

Yeah, that sounds like a bearing on one of the accessories (alternator, tensioner pulley, etc.) going bad. A mechanic may use a mechanic's stethoscope, a piece of tubing to listen through, or the old trick of listening on the handle of a long screwdriver placed on the suspect accessory to isolate the bad bearing. Of course the mechanic is going to be very, very careful near that running belt.

 

[Trav]

It could even be the water pump. I heard a Subaru water pump make similar noises.
Remove the accessory belts and run the engine briefly and listen if the noise is still there as a starting point.

 

[Vikas]

it sounds like it is coming outside of the engine

 

[oldhp]

Squirt some windex glass cleaner on the belts, I'll bet your noise goes away....for a couple of minutes.
+1 on noise outside of engine.

 

[LeakySeals]

If its the area you focus on nowhere else I suspect timing chain tensioner(s). Think that engine may have 2, one for each chain. One that sits between the sprockets right where that noise is. Another down below. Just because the noise is coming from there its no indication of which tensioner is bad though. Research and verify this. If there are 2 replace both. Take it from there.

 

[mechtech2]

Timing chain system or valves clearance.

 

[mattd]

definitely sounds valve train related.

 

[zeke1985]

So would moving up to a 10w-40 oil be too much?

 

[aquariuscsm]

Originally Posted By: zeke1985
So would moving up to a 10w-40 oil be too much?


I`d do your next oci w/10W30 with either pyb or vwb and see if you notice a difference.

 

[nicholas]

Isn't a 10w30 virtually the same vis at operating temp as a 5w30? Jumping to a 10w-40 would make for a better noise suppression, if it was indeed valve train related.

 

[johnsmellsalot]

It sounds like it's been ran low on oil a couple of times.

 

[Kruse]

While the engine is running, get a 3-foot section of heater hose and remove the oil fill cap. Stick one end inside the valve cover and the other end of the hose at your ear and listen like a stethoscope. You could also do that (carefully) around the belts or pulleys. That method should tell you if it's inside the engine or outside.

 

[Cujet]

I am going out on a limb here.

I am going to claim that those are the sounds of a worn out engine. Valve noise, timing chain noise, piston slap, and overall loose clearances.

That engine is an entire orchestra of mechanical noises.

I'd install a much more viscous oil. Not a simple change from 5W- to another 5W, but a 20W-50. If that helps, you have your answer.