2006 SR5 4x4 V6 228k

Recent oil change and recent P0174/P0171 Code (cleared after MAF cleaning) about 2 weeks ago. Although my Bank2Sensor 1 LTF trim wont go below 4.69% (idle)

2 days ago I noticed a higher pitched noise coming from the driver side engine compartment. You can hear it on start up in this video. It stays a pretty consistent pitch with RPMs. While trying to pinpoint it I had my wife shut off the car and also heard a hiss and a spark sound from the same area (hear in vid)


06 4Runner noise - YouTube

AC is off in video and doesnt change the sound when on.
Water pump and radiator changed at 175K
P/S fluid replaced 6 months ago...no change to sound when rotating wheel

Your ideas on the cause of these sounds are appreciated! Thanks!

The ticking noise at idle is normal, in my experience. What oil brand and viscosity are you using?

That whirring/whining noise immediately after startup will need a mechanic's stethoscope to isolate to the source. $20 and a great investment. It almost sounds like the starter bendix (gear) but that's an uneducated guess. Get a mech stethoscope and carefully probe the starter (thru wheelwell), alternator, belt pulleys, etc until you find the source.

UPDATE:

at 235k I noticed the sound was higher pitched for a day or two, then the battery light came on....thought it might be the alternator.

Got home to see if the battery was charging on start up, nope...11V at idle and then I saw the smoke coming from the alternator. HA!

Stock alternator lasted 235k....very nice.

Got a reman Denso unit put in and changed an the idler pulley next to the alternator cause I've had a few laying around for a few years...also changed the spark plugs. No more whine sound.

However, that hiss and spark sound when I turn the engine off is still there. You cant hear it in the cabin just when you are outside or if the hood is up. Wondering if its some sort of shutdown sequence sound like the 5th gens have that whirling sound when they shut down.


Mobil1 5W30.

Unrelated to the "hiss and spark" sound at shutdown, but my experience with Mobil 1 5W30 has been valvetrain ticking noise at hot idle. Heard it loud and clear with mechanic's stethoscope. No indication of excessive wear but the ticking was annoying.

I've had quietness with Mobil 1 0W-40 European Car, Valvoline MaxLife Synthetic Blend, and Valvoline High Mileage Synthetic. The champion of quietness has been plain old Pennzoil High Mileage conventional/synth blend.

All of these have higher concentrations of extreme pressure anti-wear additives {moly, zinc, phosphorous} than regular Mobil 1 5W-30.

With the Valvolines, I run 5W-30 in winter and 10W-30 in summer. Not sure the engine gets any benefit from switching viscosity. My engine has 270K miles on it and no doubt the bearing clearances have opened up over the years/miles.

Next oil change this fall, I'll be using Valvoline Extended Protection 5W-30. Typing this...I'm not sure why I switched from Pennzoil High Mileage other than Valvoline's rebate back when I bought it. It's cheap, it works well.

Also, post a video of the hiss and spark sound at shutdown.

No, it's not a normal shutdown sequence, if that's what you mean. If it were, we'd see questions about this sound daily.

Thank for the oil info, may try the Pennzoil in the fall. Do you just use 5W30?

I do use the Mobil 1 High Mileage version when I can find it.


Here is the video link 06 4Runner noise - YouTube

With Pennzoil High Mileage, I just used 5W-30 and valvetrain was quiet.

I watched your video (ad...seriously?) and the noise at shutdown sounded like a rattle right when the engine did the normal buck back & forth. Pull the big plastic engine cover and look around for something loose that shouldn't be. I didn't hear a hiss.

If you can't find the rattle/noise after examining, get a helper to work the ignition key so you can be right there listening and localize the noise source.

Your idle tick sounds like mine did, I think you'll be happy with Pennzoil High Mileage 5W-30. If you live in a warm climate I'd use 10W-30.