I have a 06 tj that I got second owned. It has been running good for a while, until this morning when I heard a strange noise coming from the left side of under the hood. It happened when I was going about 20 mph, then it stopped suddenly. It came back at 60 mph and now quiets down when I decelerate. It kind of sounds like a small power drill. I think it might be my alternator, since I don’t know when the last time that was replaced, and it’s getting to be about time. Anyone have any ideas what this could be?
Buzzing / humming noise
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I will try that. I revved the engine when in park to see if I heard anything. I certain it could be my belt and alternator. Both haven’t been replaced in a while.
Take the belt off and run it around the block. Start with a cold engine and keep an eye on your temp gauge. Your water pump won’t be turning and you won’t have power steering of course. You can get 10-15 minutes in before the engine hits operating temp. That’ll help you zero in on it.
or driving in the rain !or washing your engine
I’ve never had my engine covered in water from driving in the rain. Just checked from driving in to work in the rain. Dry as a bone. If you look up any procedures for engine washing, every one will tell you to avoid spraying the alternator or ignition system. You do you, what do I know.
You ford rivers to the point your alternator is submerged? You must have an awesome snorkel!
And let's be clear...get the Jeep running and give it a squirt or two and see if the squealing stops.
Don't put it in the deep end.
-Mac
Don't put it in the deep end.
-Mac
Correct me if I’m wrong. What you meant was spray the belt and not the alternator? I agree with a squirt of anything on the belt to quite it for a second. Even brakleen will do it. It didn’t sound like they were dealing with a belt squeal to me, but more like a bearing issue with an accessory by their description.
if not submerged, then deep enough for what? That doesn’t look like your oil pan even got wet
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if you run a water hose where the pulley is if the bearing is squealing it will quiet down. I aint saying to use a pressure washer and spray it in there.
I just don’t want to assume the poster knows that and he causes himself more trouble. You weren’t specific about that. Spraying it quiets the belt. You can’t get water into the bearings. They are sealed bearings.
Yep, it's an old trick. You hit the Alt with water, and the bearing will quiet down for a couple minutes until enough water is gone. Alternators are designed to be able to be wet... otherwise the engine compartment would be weather sealed, and not just the electrical connections. I have had water crossings at/just under the leading edge of the hood on many of the Jeeps I've owned over the years... never had an issue with water. All the car care manuals and recommendations I have ever read say it's ok to wash engine... just not when hot, or with pressure washer.
Edit: It's very commonly accepted that the headlight level is the max for water fording... check where the Alt is to headlight levels...
I know the trick. I mentioned it in a later post. I’ve been an auto tech all my life and I’m ocd level dedicated to my field. My intentions here are not for anyone to be right or wrong. The original statement was to spray the alternator. Implying pressured water. I’m not saying the alternator can’t tolerate water either. Just that you don’t want to spray anything directly into the alternator itself. That’s why the procedures you mentioned say not to pressure wash. From my work I’ve learned most people have little understanding of anything automotive and I had known way to know if the OP understood that. His description sounded to me like a bearing issue not a belt squeal. That’s why I mentioned removing the belt for a minute because it’s quick and easy and eliminates the belt and all accessories. Then you know if you’re even sniffing in the right area. I’ve had customers tell me they had a belt noise and it ended up being a backing plate rubbing. You can really use any liquid substance. I’ve used WD40 in a pinch. It doesn’t soak the belt. I also want to clarify that spraying the belt means it’s the belt making the noise, even if it’s from the alternator pulley. The front and rear bearings in there are a totally sealed ball bearing to keep the water out. In my experience, a bad alternator bearing sounds more like a grumbling/rumbling sound that you can feel when you touch the alternator. So in closing, all I was trying to do was help the OP find his issue, prevent him from doing any harm, and share things I’ve learned in my years. I have no intention for right or wrong, or to start any kind of crap. Anyone that was bothered but what I wrote, I’m sorry. Again, just trying to share what I learned. That’s it.
does the noise follow engine speed or vehicle speed? The front driveshaft and pinion are also under the left side of the hood...
But Buzzing/humming is what OP stated... trying to figure that one out... Alt would squeal as would belts. maybe something sheet metal is loose? Is the fan shroud in good condition and tight?
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