I noticed a slight tick on my engine while just sitting in a parking lot. Popped the hood and it drowned out the rest of the engine.
I've done some reading and people say that the V8's are just loud engines or that the timing belt needs work. (or that the manifolds cracked)
The sound is worrying, and I'd like to figure out what's causing it before I spend any money.
Any help is greatly appreciated.

Manifolds are pretty common on these as they get older. I'd start there. Do you smell any exhaust fumes under the hood? Any popping on deceleration if you blip the throttle? I verified my manifold leak on a V6 by pressuring the exhaust from the tailpipe with an air hose, I turned the pressure output down to a few pounds. Could hear the air leaking out around the exhaust manifold flange, engine off of course.

Sometimes a leaking manifold will be louder at first startup when the engine is cold.

I don't smell exhaust, no popping on deceleration either. I've known about the manifolds issue, and I try to keep an eye on it whenever I bring it in. The engine seems to run fine, until startup where it has issues starting. The starter motor is fine, but it still really heaves into every start.

It was recently pointed out to me though that it is whining as well. (It's not like a whistling sound, more like a supercharger sounding whine or what reverse gear sounds like at high revs) I'm thinking it's a timing belt or accessory drive. But if that's so it's the loudest belt I've ever heard.

I will take a look at the manifolds though. Thank you for the help.

Many times a whining noise from the engine compartment is from either the alternator going bad, serpentine belt pulleys, either the idler pulleys or the tensioner pulley bearings going bad, or power steering pump.

If the timing belt is due to be changed it could also be the idler pulleys there as well, but if not due to be changed the pulleys should last as long or longer than the belt.

Get yourself a mechanic's stereoscope at the auto part store for usually around $10+/-, everyone who does work on their own vehicles should have one in their tool box, and use it to pinpoint where the noise/whining is coming from, you can also use it to pinpoint the ticking noise as well.

Just use caution when using it around moving parts of the engine.

A few months later and I still don't know what it is. Its getting much worse. Past owners said there is a new belt, but it looks old as hell. Don't have the paperwork for that either.
Ticking can now be heard at idle and it gets extremely loud past 1500. (Drowns out even the bad rear suspension)
The whine remains the same, and I'm not really that worried about it, as long as I can remember it's done that. (I'm 90% sure it's just the power steering system)
Past owners remain adamant that the front end was worked on by the dealership prior to me getting the car.

2003 4runner V8 not happy to run - YouTube (clip of the engine being revved up to 3k)

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I can't hear anything at all in your video, could be my old ears or my laptop speakers, or it could more likely be your video's audio, getting the recording device closer to your vehicle may help, we don't need to see your vehicle just hear the engine.

No problem, will attach video(s) in a few hours.

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With better lighting the "new belt" looks awful. What's even more worrying is that one of the wheels is disintegrating and flinging rust dust everywhere.
4runner "new belt" looks awful 2000 miles later - YouTube


I don't know exactly when it was last replaced, I have an estimate. I don't see any sticker [I]anywhere[I] best guess is before I got it about 6 months ago.

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How old is that belt supposed to be? It is possible that it's a new belt.

I've seen some horribly rusted vehicles just ruin new belts rather quick. I've also seen the drive belt tensioner start failing and cause misalignment of the belt and wear them out pretty fast as well.

How do all the pulleys look, they have a lot of pitting and rust on them? The tensioner pulley should be relatively in line with all the other pulleys.

It could be 6MO or 10 years old I just don't know. But again previous owners don't know what was done to the car when it was brought in to get the front end worked on. The assumption is that yes it is new, because the past owners said that it was "last changed when it needed to be"
Pulleys are in okay shape. Except for two on the bottom left which are rusted to the point it's flinging rust on the hose below it. It feels taught, and the teeth are there.

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Oh. My. God.
So. That belt is not new. Previous owners went through service records. (They found them!)

This belt may well be the original with 187,000 miles on it. That explains the lack of any stickers about replacement as it's never been replaced.

I'm at a loss for words. I don't know how. I don't know why.


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That definitely sounds like a cracked exhaust manifold. Mine sounds exactly like it.

I'll check, I haven't done it in a hot minute. Right now I think it's just the old belt, but it couldn't hurt to check the manifolds.

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For the whine, I would buy a new belt, and while it's off spin and feel the pulleys. Any gritty feeling, noise, or anything that feels odd should be replaced. Does the noise change when the AC is on/off? Look at the belt too, in the video it sounded like someone said it's fraying, that could be slapping something as it goes around.

The ticking/knocking noise I couldn't determine through the video. Could be manifolds, could be more. As said above, grab a stethoscope and poke around (gently and carefully) and narrow down the noise.

Just an FYI, the belt you're referring too is the serpentine belt, I have never seen a sticker for the serpentine belt being replaced nor a sticker coming with a new serpentine belt to be place in the engine compartment, now on the other hand the "Timing belt" should always come with a sticker showing when it was replaced.

A serpentine belt is not as critical as the timing belt, if a serpentine belt breaks it will not usually damage much else for the most part unless it runs the water pump in which case you should shut down the engine until it's replaced, but if the timing belt breaks on many engines it will destroy the engine which is the case on the 4runner V8.

That being said if you don't see a recent sticker for the timing belt (should be replaced every 90,000 miles) or have a record of it being replaced I would be very concerned and get it replaced.

I looked at the video again and was able to hear the audio much better, I still couldn't hear any ticking/tapping noises, but I could hear some whining noises, which could be any of the moving parts, idlers pulleys/tensioner/alternator/power steering pump, etc. being turned by the serpentine belt making those noises, inspect and replace any or all if needed.

I also highly recommend as mentioned to use a mechanic's stethoscope to pin point noises in the engine compartment, you should easily be able to locate the ticking/tapping and whining noises with one, they are cheap usually around $10 or less at any auto part store, everyone should have one in their tool box!