New Member, Ticking or Knocking lx470 (2 Viewers)

[tpham18nm]

I was excited to go to work this morning and drive the LX470 there. But when I turned on the engine, it made this horrible knocking noise. I immediately turned it off and checked the oil; the oil level was fine. When I continued to diagnose the sound, it seemed like it was coming from the belt area. Right now the engine is warmed up, so I cannot replicate the noise, although it does have a higher pitch whine around the serpentine belt. I am unsure if the situation is related.

My 1998 LX470 has 176,000 miles on it. I changed the oil 1500 miles ago and it's still within the low and high mark. Completely stock. Any ideas on what is happening?

 

[TheBussman]

take the belt of and see if the noise is still there.

 

[hoser]

Loose spark plug?

 

[vipergrhd]

Grab the fan and rock it back and forth. Possible the fan bracket.

 

[Mike NXP]

Almost positive that is not engine knock or ticking. It sounds like an accessory problem for sure. If this was spark plug or internal issue it would sound worse

If you look really close you can hear the tick tick tick tick every time the white label on the belt flashes by.


However it will be a guessing game until you can get in there, remove the belt, and check all pulleys. Don't keep driving it much because if it is your fan belt about to let go that would suck, although your video doesn't show much wobble, with the belt removed it may reveal itself.

• Remove belt.
• During this first step you can feel for proper tension on the tensioner assembly. It should provide a good amount of spring back and it shouldn't feel like it's binding up or sticking
• Start engine and see if noise goes away.
• If it goes away, then it's accessor belt related. If it doesn't go away, then you have a timing belt component issue or something deeper like you initially suggested
• Assuming it goes away, start to spin and check each pulley. They should feel smooth with no free spin ( think old skateboard wheel, this is no good )

The fan bracket can't really be tested since its tucked away but like suggested above, if it's really shot you can grab it and check for wiggle

It sort of sounds like something is physically contacting the belt but I doubt it. Doesn't really sound like bad bearing but hard to tell in a video.


Post back here if you have questions and need info on how to remove belt and check further.


Question : When did you first notice the issue? Oil change 1500 miles ago, did you do it? Was it OK after that or did you just notice it now? Is the noise posted in the video what you referred to as a knocking noise or is this different?

 

[vipergrhd]

Would like to add, on my 2UZ 4runner I replaced belt, tensioner and idler pulley during my timing belt replacement and I noticed the intermittent tick went away when cold also on my pick up fan bracket (3VZE) the thing seized up right at the gas station it never made any noise it just quit after 290k miles.