Noise coming from intake manifold?

2007 NISSAN MAXIMA
244,000 MILES • 3.5L • 6 CYL • 2WD • AUTOMATIC
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DUWHOP31
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My car just started to make a high pitch coming from the back of the engine like underneath the intake manifold. I just want to see if anyone might have an idea as to what it might be? There's no other issue i.e. loss of power, etc... i can tell that could help me guess to what it is.
Oct 25, 2022 at 11:04 AM
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JACOBANDNICKOLAS
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Hi,

I'm not hearing a high pitch sound. I do hear either ticking or an exhaust leak.

If you rev the engine, does it get louder or speed up with engine speed?

Do me a favor. First, check to see if it is louder under the vehicle. If it is, check near the exhaust manifolds and where the catalytic converters attach to see if the noise could be coming from one of those areas. See pic below.

Also, if that is a top end noise, make sure the engine oil is clean and full.

Let me know.

Joe
Oct 25, 2022 at 7:09 PM
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DUWHOP31
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When i rev the engine up it does get a little bit louder and faster... the sound reminds me of when i was a kid and put brand new playing cards on my front and back bicycle spokes and drove fast down the hill. I can't tell if it is louder from the top or underneath, but yesterday i ran an OBDII scanner and the only code that popped up wad P0420 (catalyst system efficiency of your car is below threshold (Bank 1). it sounds like its coming from this area it could be coming from underneath this area too....
Oct 26, 2022 at 3:05 PM
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JACOBANDNICKOLAS
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Hi,

Since you have a catalyst code, I feel it is most likely a leak or the converter itself may be plugged.

At this point, I would allow the engine to cool off and then check to see if there is any evidence of a leak at the exhaust connections. Often times you will see black marks near the leak indicating a problem.

Let me know.

Take care,

Joe
Oct 26, 2022 at 6:12 PM