Whats that rattling noise?

[djmoreron]

newbie question again...

 

truck just started making a rattling noise recently. kinda sounds like a loose bike chain. its intermittent... happens when the truck idles or when i let off the gas while driving. sounds like its coming from underneath near the front of the engine. my guess would be timing chain?? :confused: truck drives completly normal. no loss of power or anything. any ideas?

[RacnJsn95]

Sounds like you might need to adjust your rockers?

[datzenmike]

The chain tensioner uses oil pressure from behind, (plus a spring) to push against the chain and keep it tight. At idle, the oil pressure will be much lower so maybe that's it. The chain guide may also be worn.

 

Beware, a very loose chain could rub a hole in the chain cover, not to mention the aluminum filings going through the oil pump on their way to the filter.

[Voleurz]

when i had a nissan pulsar it made a terible noise ( the timing chain) turns out the oil was too thin.

[djmoreron]

thanks for the info. wasnt sure where to begin with this. ill check what i can... and if all else fails ill call a friend of mine over to come help me out. :D

[pl521sss]

when i had a nissan pulsar it made a terible noise ( the timing chain) turns out the oil was too thin.

 

 

Or not enough Oil

 

I just had that noise a couple of days ago.

 

Checked OIL, none on the dip stick.

Yikes

 

Filled it up, no more noise on idle.

[datsunfish]

That sounds like what happened to my 620 recently.It would intermittently rattle when lettlng off the gas.Turned out to be a broken timing chain guide.Figured that out after I pulled it and threw in a different l18.Change your oil and inspect for small plastic particles.Take off the valve cover and inspect the guides from there.

[ggzilla]

The newer engines are notorious for timing chain going bad before 100,000 miles. The L-series is longer lasting.

 

But anyways it is easy to check, just pull the rocker cover and see how much slack is in it.

 

Or try the turn engine-back and see how far it moves before distributor rotor moves.

[datzenmike]

If you think about it, chain slop won't affect the dizzy, it's driven by a worm gear on the crank.

 

Gotta love the double row L and Z timing chains. Pity the KA24s with the single chain.

 

Even this angle you can see how flat the single chain KA sprocket is. Looks like the L and Z would interchange. How do you adjust for chain stretch on a KA anyway???

 

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[71-521]

while you're checking stuff, look at your water pump...try and wiggle the fan blade...if it moves you might want to change it before it eats your front cover.