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My car has/had the high pitched AC whine issue that has been reported here previously, see for example https://www.jaguarforums.com/forum/x...hine-c-165711/. There is a TSB, JTB00207, that specifies the installation of a washer in the firewall connection of the low pressure AC pipe, and has been reported to eliminate the whine. Apparently this TSB was never applied to my car by the previous (sole) owner.
I have two issues about getting this TSB applied to my car: (1) Because it is well outside warranty, I would have to pay in full for this repair, and (2) It involves evacuating and refilling the refrigerant, which I'd rather not do right at this moment as my car seems to cool just fine, and this second point also precludes a DIY application of the TSB. If and when the AC cooling performance drops off, I could get the TSB applied in the course of whatever maintenance/repair might be needed at that point. Therefore I was searching for a DIY alternative.
The fix that I came up with involves wrapping a bit (currently 12", picked at random) of
around the AC return tube. I selected the easiest accessible location, at the bottom of the car, see the pictures attached. There was no science to how I chose to wrap the wire around the tube and in-line connector - just a hand wrap to keep it tight to the tube. From an effectiveness point of view, there is definitely a sharp reduction in the whine. The whine is still there but considerably muted compared to what it had been.
Theory: Vibrations of pipes caused by internal fluid flow turbulence is hardly uncommon. In this case, it looks like the internal refrigerant flow induces a vibration at or near a resonant (natural) frequency of the return pipe. The simplest formula for natural frequency is square root of (stiffness -divided by- mass), and the amplitude of any resonant vibrations is influenced by the damping of the system. My conjecture is that Jaguar's JTB00207 introduces additional damping in the end clamping of the return pipe, hence knocking down the resonance. My alternative fix changes the mass of the return pipe and hence moves its natural frequency away from the forcing frequency of the fluid flow. Such mass dampers are also not particularly novel but mine is just a quick, dirty, and eye-balled attempt. Therefore it is not surprising that whereas the vibration has been substantially reduced, it has not been eliminated completely. I expect that if I play with the amount of lead wire (either more or less) I may see improvement, but I'm going to give it some time to see if I'm motivated to improve it further.
My car has/had the high pitched AC whine issue that has been reported here previously, see for example https://www.jaguarforums.com/forum/x...hine-c-165711/. There is a TSB, JTB00207, that specifies the installation of a washer in the firewall connection of the low pressure AC pipe, and has been reported to eliminate the whine. Apparently this TSB was never applied to my car by the previous (sole) owner.
I have two issues about getting this TSB applied to my car: (1) Because it is well outside warranty, I would have to pay in full for this repair, and (2) It involves evacuating and refilling the refrigerant, which I'd rather not do right at this moment as my car seems to cool just fine, and this second point also precludes a DIY application of the TSB. If and when the AC cooling performance drops off, I could get the TSB applied in the course of whatever maintenance/repair might be needed at that point. Therefore I was searching for a DIY alternative.
The fix that I came up with involves wrapping a bit (currently 12", picked at random) of 3/16" lead wire around the AC return tube. I selected the easiest accessible location, at the bottom of the car, see the pictures attached. There was no science to how I chose to wrap the wire around the tube and in-line connector - just a hand wrap to keep it tight to the tube. From an effectiveness point of view, there is definitely a sharp reduction in the whine. The whine is still there but considerably muted compared to what it had been.
Theory: Vibrations of pipes caused by internal fluid flow turbulence is hardly uncommon. In this case, it looks like the internal refrigerant flow induces a vibration at or near a resonant (natural) frequency of the return pipe. The simplest formula for natural frequency is square root of (stiffness -divided by- mass), and the amplitude of any resonant vibrations is influenced by the damping of the system. My conjecture is that Jaguar's JTB00207 introduces additional damping in the end clamping of the return pipe, hence knocking down the resonance. My alternative fix changes the mass of the return pipe and hence moves its natural frequency away from the forcing frequency of the fluid flow. Such mass dampers are also not particularly novel but mine is just a quick, dirty, and eye-balled attempt. Therefore it is not surprising that whereas the vibration has been substantially reduced, it has not been eliminated completely. I expect that if I play with the amount of lead wire (either more or less) I may see improvement, but I'm going to give it some time to see if I'm motivated to improve it further.
I hope this helps the X150 community!
I also noticed that faint high pitch sound coming from mine ... Will have to give this a try and see too. Thx!
The fix that I came up with involves wrapping a bit (currently 12", picked at random) of 3/16" lead wire around the AC return tube. I selected the easiest accessible location, at the bottom of the car, see the pictures attached. There was no science to how I chose to wrap the wire around the tube and in-line connector - just a hand wrap to keep it tight to the tube. From an effectiveness point of view, there is definitely a sharp reduction in the whine. The whine is still there but considerably muted compared to what it had been.
Theory: Vibrations of pipes caused by internal fluid flow turbulence is hardly uncommon. In this case, it looks like the internal refrigerant flow induces a vibration at or near a resonant (natural) frequency of the return pipe. The simplest formula for natural frequency is square root of (stiffness -divided by- mass), and the amplitude of any resonant vibrations is influenced by the damping of the system. My conjecture is that Jaguar's JTB00207 introduces additional damping in the end clamping of the return pipe, hence knocking down the resonance. My alternative fix changes the mass of the return pipe and hence moves its natural frequency away from the forcing frequency of the fluid flow. Such mass dampers are also not particularly novel but mine is just a quick, dirty, and eye-balled attempt. Therefore it is not surprising that whereas the vibration has been substantially reduced, it has not been eliminated completely. I expect that if I play with the amount of lead wire (either more or less) I may see improvement, but I'm going to give it some time to see if I'm motivated to improve it further.
I hope this helps the X150 community!
Same idea is used onboard ships to quiet resonances in ship piping. Basically minimizing vibrations by changing the mass loading at strategic points on an offending pipe as you describe. Metal strips (steel I believe) are placed all around the pipe and firmly banded in place.
Good job!
08-18-2022, 05:59 PM
AC whine DIY fix, application and theory
