Car vibration when the A/C is turned on?

Tiny
HASSANMAHMOOD
  • MEMBER
  • 2019 JEEP GRAND CHEROKEE
  • 3.6L
  • V6
  • 4WD
  • AUTOMATIC
  • 53,000 MILES
Hello, glad to be helped,

My vehicle starts vibrating, few seconds after I turn the A/C on.
So, I heard that the cooling fan may be the cause for that, I had a video recorded and might help diagnosing that.
I am in doubt whether this is the cause or something else.
Friday, July 26th, 2024 AT 3:43 PM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,645 POSTS
Hi,

Is there play in the fan blade? In other words, can you wiggle it on its mount? Also, that really doesn't look too out of the ordinary. How low do the engine RPM's get when the A/C is on, and you notice the vibration?

Do me a favor. Start the engine and turn on the A/C until you feel the vibration. Increase the engine RPMs slightly (approximately 1,500 RPMs) and see if the vibration stops.

Let me know what you find.

Joe
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Sunday, July 28th, 2024 AT 6:56 PM
Tiny
HASSANMAHMOOD
  • MEMBER
  • 17 POSTS
Sir, the vibrations end even at 1,000 RPMs, but related to what you said about if the fan wiggles around its mount, I attached a video sir.
Thanks again.
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Monday, July 29th, 2024 AT 3:22 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,645 POSTS
Hi,

The movement in the fan seems okay and not excessive. When the fan is on and you feel the vibration, how low are the engine RPMs? If the vibration goes away at 1,000 RPMs, that leads me to think the engine idle speed is too low when the load from the A/C compressor is added. If it was the fan itself causing the vibration, it would continue even after 1,000 RPMs.

Let me know.

Joe
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Monday, July 29th, 2024 AT 10:37 AM
Tiny
HASSANMAHMOOD
  • MEMBER
  • 17 POSTS
Sir, I think it does not increase on ac start!
I have a video recorded for that.
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Monday, July 29th, 2024 AT 3:01 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,645 POSTS
Hi,

The engine speed appears to be fine. Do me a favor. Check to make sure nothing is loose. Check the mounting bolts on the A/C compressor itself.

Let me know.

Joe
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Tuesday, July 30th, 2024 AT 11:46 AM
Tiny
HASSANMAHMOOD
  • MEMBER
  • 17 POSTS
Sir, the bolts are tight already.I made sure of that.
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Friday, August 2nd, 2024 AT 2:24 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,276 POSTS
I see you spinning the fan which looks okay from this angle, but I have seen a piece of plastic break from the fan blade which will cause it to be off balance. Also, if the A/C system is over charged or has too much compressor oil in it the system will vibrate, let's go over this video to see what the pressures should be:

https://youtu.be/4EqdrBVb0sY?si=kw5WoPtRGFs6y3XH

Check out the images (below). Please upload pictures or videos in your response of any problems so we can see what to help you with.

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Saturday, August 3rd, 2024 AT 6:01 PM

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