Engine Whine the Day I Hit 150k

[07V8]

My truck was going to hit 150,000 flawless today miles until this morning when I turned it on and heard a slight whine from the engine compartment. My initial thoughts were the emission control fan/valves that are issues on the 4.7l in the Tundra and some 4Runners with VVT-i. However, since it was not as loud as those failures, I think I may have a bearing on the way out. I don’t think it’s a vacuum leak because it’s not pneumatic or a “hissing” sound and the truck idles fine.

The faint whine sounds like a noisy power steering pump; however, it’s always there (in gear/park) and changes with RPM. It’s faint and can be heard better inside the car than out with the hood open. My initial thoughts are the alternator or some rotating pulley/accessory on the serpentine belt. The water pump, serpentine belt, tensioners, and idlers were all replaced at 92k. The alternator is original and I do have an aftermarket stereo that could have shortened the life of it. I imagine increased electrical draw would increase the load on the bearings.*

Any thoughts?

 

[fdbyrne]

I'd suggest that you pull the serpentine belt and then check all of the various pulleys for play.

I once replaced my power steering pump because I was certain that is what I was hearing. All that work and the noise didn't change. It ended up being two of my idler pulleys. When I got the belt off it was easy to tell that the pulleys were bad because there was a noticeable wobble in two of them.

 

[Atlanta_man]

Mine does the same thing, almost two years now...most noticeable when cruising the freeway

no change over time yet, I keep hoping it will get loud enough to locate with some precision

 

[fdbyrne]

Mine sounded like it grew a turbocharger.

 

[07V8]

It's very slight. You can barely hear it above 25mph. It's more evident inside the car than out.

 

[4Rnr4Evr]

Mine whines quite a bit, shop said don't worry about it. One day when I have nothing better to do I'll take off the belt and check all pulleys.

 

[fdbyrne]

It's a really easy fix. It only takes about an hour. You don't have to remove the fan or anything although it would be easier if you did.

 

[07V8]

I did some more troubleshooting.

On the way home, voltage dropped to 11.1 with the air, headlights, and stereo on. I pulled into O'Reillys and failed an alternator test.

Drove 25 miles home and the sound is gone and voltage is back to normal. Could something have caused the belt to slip? I feel like electrical issues are either present or not. The fact that it's back to normal leaves me to believe there was a mechanical issue that worked its way out.

 

[nevada]

I did some more troubleshooting.

On the way home, voltage dropped to 11.1 with the air, headlights, and stereo on. I pulled into O'Reillys and failed an alternator test.

Drove 25 miles home and the sound is gone and voltage is back to normal. Could something have caused the belt to slip? I feel like electrical issues are either present or not. The fact that it's back to normal leaves me to believe there was a mechanical issue that worked its way out.

prepare to replace the alternator.

 

[07V8]

prepare to replace the alternator.

That's what I'm thinking. The sound is every so slightly present.

 

[gone_primal]

Almost exact same symptoms when my alternator went out. If you can measure voltage at the terminals while the engine is running and it is less than what it is while off then your alternator is dying. Mine ran and drove right up until it didn't.

 

[07V8]

Almost exact same symptoms when my alternator went out. If you can measure voltage at the terminals while the engine is running and it is less than what it is while off then your alternator is dying. Mine ran and drove right up until it didn't.

Just did and saw 13.0V off and 13.4V while running. This was after the whining and low voltage readings I saw this morning and the start of my commute home.

Did yours whine? Was it intermittent? How long before complete failure?

Went to the dealer and the master tech recommended waiting on replacing it.

 

[gone_primal]

Mine was not intermittent. Whine started and got progressively worse over 2 days. Ran fine until I picked up the new alt and by the time I got home I could smell it burning.

 

[07V8]

Mine was not intermittent. Whine started and got progressively worse over 2 days. Ran fine until I picked up the new alt and by the time I got home I could smell it burning.

Thanks for the reply.

I'll keep an eye on mine - if it happens again it will be replaced.

 

[radlynx]

you should replace it now. don't wait until it's too late. you can get stranded somewhere and pay for towing if too far away or worse case scenario, pay the dealer for repair if you are in a remote location which may cost a lot higher. and for your own peace of mind. see my point?

Thanks for the reply.

I'll keep an eye on mine - if it happens again it will be replaced.

 

[malcadam]

OK , 07V8, here we are 6 years later, I have same issue, same analysis, same mileage. You are probably no longer monitoring this, but if you are, what was the final resolution?
To others..... what can I expect?

malcadam