Rattling/Rubbing noise from engine bay

Hi guys i’m new here, have seen lots of info in the past here but never joined until now. Heading a rubbing noise almost like a grinding but not quite. Thought maybe it was the AC compressor because it’s worse when the ac is on. Noticed the sound is still there just not as prominent with the ac off. Not the compressor or the clutch since it wouldn’t be turning when the system is disengaged? Any thoughts on what this could be? Thanks.

 

Hello, Eyan. Welcome to TacomaWorld.

Please give some additional information about your truck and the nature of the noise. 4 or 6 cyl, auto/manual trans, odometer reading. Also, did the noise start suddenly, or come on gradually? Did it happen right after some maintenance was done?

With nothing else to go on, assuming it’s got the 4.0L V6, the first thing I’d suggest is to remove the serpentine belt and start the engine to see if the noise is gone. With a cold engine, you can run it for a couple of minutes without concern about overheating. If the noise is no longer present, then one of the spinning parts has a bad bearing. Idler pulleys, tensioner pulley, water pump, A/C, power steering, or alternator. If any of the idler/tensioner pulleys spin too easily and sound like an old metal skateboard wheel when spun by hand, that’s likely the culprit.

 

It is the 4.0 v6, auto transmission and gradually worse over time. It’s worse when the ac is on but still kind of faint when the ac is off. Just changed water pump and thermostat because i had a coolant leak. Was fine but now the rubbing has been getting worse.

 

Yeah, do the easy thing first and check those bearings. My ‘11 had a bad bearing in an idler, it spun freely for quite a while before stopping when spun by hand. It had no grease left inside, I’m sure. But it wasn’t making any obvious noise, strangely enough.

Do a search, there are a couple of threads regarding replacing the serpentine belt and pulleys. Getting the belt off is pretty easy from underneath the truck.

 

Okay sounds good, I appreciate the input. I’ll check the bearings first and then go from there. Thanks again.

 

Yes take the belt off and check all the pulleys. The AC pulley is still spinning even with the magnetic clutch not engaged so if those bearings are going bad it will make noise any time the engine is running

 

Did you ever find out what caused the 'rubbing noise almost like a grinding but not quite' sound? In my case, it turned out to be the 'foam doughnut' on the end of the air intake hose going into the fender that had deteriorated. The vibration was noticeable mostly at idle with a/c both on or off. All quiet now

$6 Frost King R734H Sponge Rubber Foam Tape 3/4" W X 7/16" H X 10' L, Black

https://www.amazon.com/Frost-King-R...a6a-a7e4-20649709bc53&pd_rd_i=B0000CBIFD&th=1

 

Hey I appreciate the response. So I changed left the compressor because the ac has still been working perfect, I changed the clutch and pulley on the compressor though. Noise seems to be better but still not completely gone, not too sure at this point.

 

Have you tried checking for the noise without the serpentine belt on? That seemed like a good place to start & would cover a lot of spinning parts.

Watching for the solution.

 

No I definitely should’ve checked when I had the belt off, stupid mistake. I’ll get back to y’all when I get a chance to get back in there. Just got my long travel kit so going to occupied with that for a little while lol.

 

Loosen the clamp at your air intake hose box and twist the hose to the rear. Tighten it back down with tension on the hose and see if the rattle noise goes away.

 

Was it making the noise BEFORE you changed the parts? Look over your work and everything that you touched.

 

Okay I will try that and yes the noise was there before the work was done. Going to try looking at the clamp on the air intake right now

 

Any updates OP?

 

It’s definitely coming from something on the belt. I did what these guys recommended with the intake, still have noise. Sounds like it is coming from around the alternator. Originally I thought it was the compressor and I changed the ac clutch. The noise is still there and the ac blows hard/ cold, so not convinced it’s that. The noise is more prominent when the ac engages, not sure if it’s because more energy being pulled from the belt? I’m leaning towards a bad pulley on the alternator or the idler. I need to pull the belt off still and see.

Sorry I don’t post frequently, i’ll try and keep this updated.

 

Thanks, I'm currently trying to track down a similar noise on my '02.

 

No problem, let me know if you get yours figured out.

 

One of these works wonders, just be careful when using it.

$12 Performance Tool W80582 Automotive Stethoscope

https://www.amazon.com/Performance-...239576&sprefix=engine+ste,aps,326&sr=8-7&th=1

 

Thanks! I’ll try that and see if I can do it without losing a finger or two lol.

 

Automotive stethoscope is a great tool to detect the source of noises without getting your hands to close. My noise is coming from the A/C clutch, researching to see if I can change the A/C clutch without removing the compressor.