Engine sound from serpentine belt area?

2016 TOYOTA CAMRY
150,000 MILES • 4 CYL • 2WD • AUTOMATIC
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BHAMDOC1973
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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
Jul 28, 2025 at 4:07 PM
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STRAILER
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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
Jul 28, 2025 at 7:19 PM
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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
Jul 29, 2025 at 3:25 PM
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STRAILER
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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.
Jul 30, 2025 at 9:18 AM
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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
Jul 30, 2025 at 3:30 PM
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STRAILER
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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
Jul 30, 2025 at 5:30 PM
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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
Aug 2, 2025 at 11:18 AM
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STRAILER
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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.
Aug 2, 2025 at 11:32 AM
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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
Aug 2, 2025 at 11:37 AM
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STRAILER
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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.
Aug 3, 2025 at 11:16 AM
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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
Sep 1, 2025 at 5:30 AM
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STRAILER
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I thought it was the compressor no?
Sep 1, 2025 at 9:03 AM
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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
Sep 1, 2025 at 9:27 AM
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BHAMDOC1973
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Is it possible spark plugs pre detonation coupd be that noise i sent you a video of
Sep 1, 2025 at 11:57 AM
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BHAMDOC1973
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Spark plugs lugs look ok. Plz look at this chaon
Sep 1, 2025 at 12:09 PM
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STRAILER
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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.
Sep 2, 2025 at 7:59 PM
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BHAMDOC1973
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Ya i have to remove it. Thanks
Sep 3, 2025 at 4:19 AM
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STRAILER
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Sounds good, I believe that is your problem.
Sep 3, 2025 at 8:24 AM
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BHAMDOC1973
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Removed it and found this plz see videos
Sep 3, 2025 at 11:13 AM
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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?
Sep 3, 2025 at 11:26 AM
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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
Sep 3, 2025 at 11:41 AM
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STRAILER
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Yep, you found the problem, the timing chain, tensioner and guides need to be replaced. They make a kit with all of these with seals to help with the repair. Nice work getting the front off of the engine so fast :) Thanks for the videos! They help.
Sep 3, 2025 at 1:50 PM
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BHAMDOC1973
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ugh, I hate replacing chains. I done it on a vw once and I cussed the whole time through it lol. This is much easier am sure. My only concern is if I replace both cam gears or phasers, after removing the chain, just hold the cam with a wrench and remove the camshaft gear bolt? you ever heard of the engine oil pumps from inside the oil pan go weak and cause such noise?
Sep 3, 2025 at 2:02 PM
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BHAMDOC1973
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any brand you recommend other than the dealership so I don't break the bank?
Sep 3, 2025 at 2:02 PM
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BHAMDOC1973
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also do you know which RTV silicone is recommended for the cover
Sep 3, 2025 at 2:47 PM
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STRAILER
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We should start a new thread to continue with the job. Please post your new question here, you must be logged in.

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

Cheers, Ken
Sep 3, 2025 at 6:08 PM
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BHAMDOC1973
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Started the car the old noise is gone but there is still some ticking not sure if from chain area or under the valve cover. Not sure if this is normal. Noise that used to pop when ac was on is gone. I am 100% i did everything right and no checm engine light or codes
Sep 12, 2025 at 7:20 AM
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STRAILER
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That ticking sounds normal to me, like it is the fuel injectors.
Sep 12, 2025 at 9:29 AM
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BHAMDOC1973
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That is what i thought, and i read in many places that these motors are noisy. Thanks
Sep 12, 2025 at 9:48 AM
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STRAILER
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You are welcome, please use 2CarPros anytime we are here to help.
Sep 14, 2025 at 10:13 AM