My 2011 XJL supercharge is making a strange noise when I'm driving it. The noise sounds like a gargling noise. It almost sounds like a gear box with no lubrication...just a strange growling or gargling noise. It only makes this noise when I'm in the "neutral" spot between accelerating and decelerating. The noise stops when I accelerate or I take my foot off the accelerator. The noise is coming from the passenger side just under the front passenger door. When I'm in park, I can rev up the engine and no noise is made. It only happens when the car is in gear and while driving and just between the time I'm in that neutral spot between speeding up and slowing down. The Jag dealer thought it might be a water pump so they changed that out and the noise is still happening. Any suggestions on what could cause this?

 

You tried ac on and off on the noise?

 

Yes. The climate control was off and the radio was off too. This noise is so annoying.

 

I had an odd noise from that general vicinity and tracked it down to a loose heat shield that was coming into contact with the exhaust and making an odd rattling sound.

Which water pump was replaced? The main coolant pump on the front of the engine, or the auxiliary heat pump next to the radiator? Was the dealer service department's theory that a failing pump was causing coolant to gurgle in the heater core?

Cheers,

Don

 

Could be the catalytic converter also. Mine currently makes noise. In park or neutral rev to about 3000 RPMs and see if it make noise on the deceleration.

 

The water pump in the front of the engine was replaced, not the other one. The dealership did assume the noise was the result of water entering the heater core. They sold me on that because of the area of the noise. It sounded just like water gurgling in that general area. That was an $800 waste of money. I will check the heat shield. Its odd that the noise only happens between acceleration and deceleration, right at the neutral sweet spot when there is very little strain on the gear box. That's about the best I can explain it.

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