Engine sound from serpentine belt area?

Tiny
BHAMDOC1973
  • MEMBER
  • 2016 TOYOTA CAMRY
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 150,000 MILES
Only when ac compressor comes on there is a loud tapping/knocking sound. Oil is good, ac is super cold, am sure sound is not from the compressor. Here are 2 videos
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Monday, July 28th, 2025 AT 4:07 PM

29 Replies

Tiny
KEN L
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So you say you are sure it is not from the compressor? It sounds like it is making the noise which it is possible for the compressor to work but still make noise. With the engine off, grasp the AC compressor clutch and spin it by hand, it should be smooth with a slight resistance. If all is good, the problem can be the harmonic balancer or the timing chain system is worn out, ie: timing chain, guides tensioner, camshaft phasers. You might want to remove the serpentine belt to help the inspection. Check out the images (below). Let us know how it goes
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Monday, July 28th, 2025 AT 7:19 PM
Tiny
BHAMDOC1973
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I did remove the belt and the compressor turns by hand fine no problem and the AC is super cold but when I also replaced the tensioner from my wife's car same results so my question is if I remove the belt and turn the AC on will the clutch still make the same noise if it's the reason behind the noise or does it need to be turning with a belt to make that noise? How can I determine whether the noise is coming from the harmonic balancer or from the compressor
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Tuesday, July 29th, 2025 AT 3:25 PM
Tiny
KEN L
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The harmonic balancer will be loose at the outer ring. It might have a broken crankshaft as well. I would remove the belt and then turn on the AC to see what happens, my guess is the noise will stay the same as the load of the compressor makes the engine make the noise but you never know.
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Wednesday, July 30th, 2025 AT 9:18 AM
Tiny
BHAMDOC1973
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Removed the belt, but the compressor only turns when the belt is on even with the ac button pressed. No noise now but not sure if its the compressor or the load of the compressor causes the engine to knock. Harmonic balancer spins fine no sign of issues at all no wobble and not loose
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Wednesday, July 30th, 2025 AT 3:30 PM
Tiny
KEN L
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Then it has to be the compressor, I would install a new or used unit. If you need help please start a new thread for it. Please post your new question here, you must be logged in.

https://www.2carpros.com/questions/new

Cheers, Ken
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Wednesday, July 30th, 2025 AT 5:30 PM
Tiny
BHAMDOC1973
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Replaced it with a used one, unfortunately it is coming from the engine, ugh, mainly from chain area on top
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Saturday, August 2nd, 2025 AT 11:18 AM
Tiny
KEN L
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I am sorry to hear that, it must be the load from the compressor that causes it. This is a rare problem FYI.
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Saturday, August 2nd, 2025 AT 11:32 AM
Tiny
BHAMDOC1973
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Hmm, ya I know with Toyotas hard to happen, but the car has 198k actually I made a mistake of putting 150k in the beginning
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Saturday, August 2nd, 2025 AT 11:37 AM
Tiny
KEN L
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Good to know, thanks for the problem, that is one good thing about the web I get to see all problems, this was a new one for me.
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Sunday, August 3rd, 2025 AT 11:16 AM
Tiny
BHAMDOC1973
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I removed the valve cover still dont see anything. Hard to move the chain around to see if any slack, any ideas on how to remove the chain metal cover? I giess I have to. And wherher I need to remove the tensioner to remove the cover, and which side is it on
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Monday, September 1st, 2025 AT 5:30 AM
Tiny
KEN L
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I thought it was the compressor no?
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Monday, September 1st, 2025 AT 9:03 AM
Tiny
BHAMDOC1973
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No it didnt solve the issue. Even with compressor off still have that noise. I thought maybe I could see something with cover off but definitely an inside noise. Also the belt tensioner and belt replaced
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Monday, September 1st, 2025 AT 9:27 AM
Tiny
BHAMDOC1973
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Is it possible spark plugs pre detonation coupd be that noise I sent you a video of
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Monday, September 1st, 2025 AT 11:57 AM
Tiny
BHAMDOC1973
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Spark plugs lugs look ok. Plz look at this chaon
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Monday, September 1st, 2025 AT 12:09 PM
Tiny
KEN L
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Yep that seems lose, I would try to look down inside the engine timing cover to check the chain further and look for broken pieces such as the tensioner or guides thank for the video, it helps. You might need to remove the timing cover completely for the inspection.
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Tuesday, September 2nd, 2025 AT 7:59 PM
Tiny
BHAMDOC1973
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Ya I have to remove it. Thanks
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Wednesday, September 3rd, 2025 AT 4:19 AM
Tiny
KEN L
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Sounds good, I believe that is your problem.
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Wednesday, September 3rd, 2025 AT 8:24 AM
Tiny
BHAMDOC1973
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Removed it and found this plz see videos
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Wednesday, September 3rd, 2025 AT 11:13 AM
Tiny
BHAMDOC1973
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Not sure if this ppay is acceptable because the guide coles with just one bolt and the other side is held by the tensioner tension?
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Wednesday, September 3rd, 2025 AT 11:26 AM
Tiny
BHAMDOC1973
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I placed it on TDC and the top and bottom marks line up but not the chain colored ones so at least I know its in time
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Wednesday, September 3rd, 2025 AT 11:41 AM

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