2007 4.0 V6 Engine Whining at Idle

[Derek]

Hello,

Today I cranked my 2007 4.0 V6 4Runner and there was a very noticeable whining sound coming from the engine. It sounded like it was mostly concentrated near the front on the driver side. Here is a video of the sound:

https://youtu.be/4sHvuOE1afk

I drove it a few miles to the store and when I cranked it to leave the sound was not as loud. Then I went to another store and when I left that store I could barely hear it. Either way I'd like to diagnose and fix the problem ASAP. Anyone have any thoughts on what this could be? Thanks!

 

[importman]

Hello,

Today I cranked my 2007 4.0 V6 4Runner and there was a very noticeable whining sound coming from the engine. It sounded like it was mostly concentrated near the front on the driver side. Here is a video of the sound:

https://youtu.be/4sHvuOE1afk

I drove it a few miles to the store and when I cranked it to leave the sound was not as loud. Then I went to another store and when I left that store I could barely hear it. Either way I'd like to diagnose and fix the problem ASAP. Anyone have any thoughts on what this could be? Thanks!

Well it sounds like the power steering pump but you said it seems to be coming from the driver's side. The pump is on the passenger side. So I'd suspect a bearing in either the alternator or possibly one of the idler/tensioner pulleys. The best way to find it would be with a mechanic's stethoscope but if you don't have one you can use a long screwdriver. But first, I'd check the power steering fluid level just to be sure. The fact that it lessened as you drove it points toward the power steering pump. If the fluid is low it will whine like that and as it warms up and the fluid expands it will sometimes go away. If it's not that you can very carefully take a long screwdriver and put the point on the alternator and the center bolt of the other pulleys and place your ear on the end of the handle. You should be able to tell which place is making the noise. Be very careful to not let the screwdriver get into the fan or the belt. And if you do use a stethoscope it can hurt your ears if the probe hits the fan etc.

 

[Derek]

Well it sounds like the power steering pump but you said it seems to be coming from the driver's side. The pump is on the passenger side. So I'd suspect a bearing in either the alternator or possibly one of the idler/tensioner pulleys. The best way to find it would be with a mechanic's stethoscope but if you don't have one you can use a long screwdriver. But first, I'd check the power steering fluid level just to be sure. The fact that it lessened as you drove it points toward the power steering pump. If the fluid is low it will whine like that and as it warms up and the fluid expands it will sometimes go away. If it's not that you can very carefully take a long screwdriver and put the point on the alternator and the center bolt of the other pulleys and place your ear on the end of the handle. You should be able to tell which place is making the noise. Be very careful to not let the screwdriver get into the fan or the belt. And if you do use a stethoscope it can hurt your ears if the probe hits the fan etc.

Thanks for the quick reply. It was difficult to tell whether it was louder on one side or the other. When I was stopped at a red light I did move the steering wheel slightly and when the idle dropped just a little the whining sound also changed. I hadn't considered power steering. I suppose it could also be an alternator. I just hit 194K miles today so I guess anything is possible.

 

[UZmattman]

That sounds a lot like my Accord's whine when it got really cold. I replaced an O ring on one of the hoses and that fixed it. Once warmed up it would go away.

Atlanta isn't really cold so I would let the truck cool right down to your lowest overnight temp and do a cold start. Then use a long screwdriver and listen.

If it's the alternator, I would start seeing issues with ac/fan speeds etc. Basically look for a voltage drop on the battery.

If it's the PS, then you should hear a noise as you turn the steering wheel full left/right when you're on a cold start.

 

[gm350reratliff]

It could be a idler/tensioner pulley, alternator, or the A/C compressor. On my 2008, the AC compressor has been whining on and off for about 10 years but hasn't failed yet and the AC is still ice cold so I haven't replaced it yet. YMMV

 

[Derek]

Thanks for all the feedback. I cranked it a few times today and couldn't get the loud whining sound to come back. It may have been there but it wasn't loud enough to be noticeable. One thing I did notice was an oily substance on the passenger side of the engine around the valve gasket. Is this something I should be concerned about? Here are some pictures (first picture is the drivers side for comparison):

 

[gm350reratliff]

Looks like you have some seeping valve cover gaskets. I wouldn't say it's an emergency repair but probably something you'll have to repair at some point.

 

[Seymore Butts]

That is precisely what a failing alternator sounds like.

 

[ktom3001]

That is precisely what a failing alternator sounds like.

This

 

[Derek]

That is precisely what a failing alternator sounds like.

What’s odd is I haven’t heard it again since Saturday when the video was taken. I was planning to drop it off at the dealer service department this morning but if it’s not making the noise then they won’t know what’s wrong. Is there anything I can do to help confirm it’s the alternator?

 

[Jakeepoo3]

Steering pump most likely. Check voltage output at alternator for quick check there. If you want to take the belt off you can check the pulleys by hand turning. That's the noise I heard right before my pump seized up and actually prevented my truck from starting! Scared me for a minute.

 

[Jakeepoo3]

Be careful with an intermittent issue like that and the dealership. That's their favorite way to f_ck you and replace the cause of the issue last.

 

[firebirdguy]

id stay away from a dealership unless under warranty still, they are THE most expensive option to work on an older car. take it to a reputable local mechanic/shop or even one of the larger places like goodyear, firestone, etc.

definitely do what you can yourself, the screwdriver trick works good but if you dont have a long screwdriver you can cut a piece of old garden hose & do the same thing to see if you can determine whats causing the issue.

& at 194k its a good idea to flush the power steering fluid or do a few drain & fills with a turkey baster or pump from a hand lotion bottle... & use the correct fluid, dexrron3, not universal power steering fluid.

in the vid i heard the noise change from something, did you or someone turn the wheel slightly? or turn on something with a heavy load like headlights or a/c etc? something caused the noise to change & whatever it was would likely be the culprit. report back with what you find.

& on the valve cover residue, looks like minor seepage built up over a long time, nothing wet or fresh oil. i would wipre it down & monitor it to see how quick it comes back. can also gently check the valve cover bolts & snug them up a tad. at 194k miles it would be a good idea to start using a high mileage oil like valvoline maxlife or any other decent brand, it is a more robust oil & has conditioners in it to soften up seals & gaskets to prevent leaks & prolong their life.

 

[Derek]

id stay away from a dealership unless under warranty still, they are THE most expensive option to work on an older car. take it to a reputable local mechanic/shop or even one of the larger places like goodyear, firestone, etc.

definitely do what you can yourself, the screwdriver trick works good but if you dont have a long screwdriver you can cut a piece of old garden hose & do the same thing to see if you can determine whats causing the issue.

& at 194k its a good idea to flush the power steering fluid or do a few drain & fills with a turkey baster or pump from a hand lotion bottle... & use the correct fluid, dexrron3, not universal power steering fluid.

in the vid i heard the noise change from something, did you or someone turn the wheel slightly? or turn on something with a heavy load like headlights or a/c etc? something caused the noise to change & whatever it was would likely be the culprit. report back with what you find.

& on the valve cover residue, looks like minor seepage built up over a long time, nothing wet or fresh oil. i would wipre it down 7 monitor it to see how quick it comes back. can also gently check the valve cover bolts & snug them up a tad. at 194k miles it would be a good idea to start using a high mileage oil like valvoline maxlife or any other decent brand, it is a more robust oil & has conditioners in it to soften up seals & gaskets to prevent leaks & prolong their life.

These are all good points. I don't mind paying a little more at the dealership. I just want it fixed the right way. I travel for work Mon-Fri most weeks so I don't have much time to do my own work these days unfortunately. When the sound changed I believe it was when the electronic brake booster kicked on like it typically does. We have a trip planned in April so I want to be confident that this will be reliable like it has been in the past. I have always changed the oil every 5K miles with Mobil1 (regular stuff, not high-mileage) but I could switch with the next change at 195K. Without it making the sound right now I'm wondering how much troubleshooting can be done.

 

[ahs46]

I had the exact same issue and sound on my 2006 V6. I got the sound randomly one day while pulling into my office parking lot then it stopped for months. When it came back it was constant and got louder the longer I drove it. I ended up replacing the idlers and tensioners first to see if that made a difference but the sound was still there. I replaced the alternator and boom the sound was completely gone. I’d recommend replacing your idlers and tensioners while you’re in there. Mine were feeling pretty rough.


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[firebirdguy]

These are all good points. I don't mind paying a little more at the dealership. I just want it fixed the right way. I travel for work Mon-Fri most weeks so I don't have much time to do my own work these days unfortunately. When the sound changed I believe it was when the electronic brake booster kicked on like it typically does. We have a trip planned in April so I want to be confident that this will be reliable like it has been in the past. I have always changed the oil every 5K miles with Mobil1 (regular stuff, not high-mileage) but I could switch with the next change at 195K. Without it making the sound right now I'm wondering how much troubleshooting can be done.

thats fine if you are ok with using the dealership... but a reputable mechanic or larger chain shop will fix it the right way too. ive heard just as many if not more horror stories of dealership mechanics than normal mechanics.

diagnosing a bad alt or other parts like idler pulleys etc is pretty straight forward & any decent shop can do that just as well as a dealership, & they wont charge as much for the labor or the parts. but yes if its not making the noise it may be harder to verify what it is/was. just a suggestion to save some money. hope it works out for you.

 

[Drcoffee]

What I do when isolating a bearing screech is with motor running, spray WD40 using the straw, on each pulley bearing right where the bolt meets the bearing race. Its thin so it penetrated into the bearing while its running. It wont last more than a minute or two but it will quiet the screech on the offending bearing.momentarily. Id guess on the idler/tensioner pulley. They are quasi sealed and water and dirt can ruin them fairly easily.

I also buy skf, koyo 6203 bearing buy the dozen. When I change the serp belt, I change pulley bearings. On these trucks, I think the only one I can replace the bearing on is the tensioner because of the bolt/inner race diameter is different. Idlers, just buy a new pulley. Tensioner, I use two 6203 bearings to make sure its as wide as the oem bearing 5203. Two bearings are 1/16” wider than one 5203 bearing. Bolts on just fine.

I just replaced the water pump on my mothers Lincoln town car. Both idler and tensioner use 6203 bearings so it was a quick and cheap repair to swap out bearings while I had it apart. These bearings are universal in the auto industry.

The bearings are $6 each on ebay.

 

[importman]

I still suggest listening to each component with a stethoscope or screwdriver. Do it while the noise is actually occurring. You should be able to identify the source that way.

 

[Derek]

So I ended up replacing the alternator myself over the weekend. The noise would come and go so it's probably too early to know whether this was the problem. But at least I've got a new alternator and it was only ~$170 (OEM) from Toyota. I'm hoping this is the fix but if not then at least I can eliminate it. I also changed the oil and used Mobil1 High Mileage as suggested. Thanks again for all the suggestions and help!

 

[ktom3001]

My alternator started whining and then stopped, right as my battery light came on.