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Knocking Noise from Underneath the car when Idling/at Idle


joswald21

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Hello...we bought our MKZ on 2017-11-25.

 

My wife and I have both heard a rhythmic knocking noise that seems to occur after the car has been idling for several minutes.

 

I'm 95% sure that it's coming from underneath the car.  It seems to be loudest at the rear floor just behind the front seats.  It MAY even be happening more toward the driver's side of the car.

 

Is anyone else hearing the same kinda thing?

 

Any ideas?

Edited by joswald21
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The car (2017 MKZ 2.0 AWD) was at the dealer today.  They say that they only heard the normal EcoBoost High Injection Pump noise characteristic of the 2.0 turbo.

 

What I don't know is whether that is the same noise my wife and I heard.  I don't know for sure, but I think the pump noise would come from under the hood.

 

The next time I hear the noise, I'll be sure to make a quick video.

Edited by joswald21
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Sounds like BS to me.  I've had  several 2.0 service loaners and have never heard any knocking noise under the floor.  AFAIK, high pressure GDI pumps don't make knocking sounds.  Complaints about noise with these usually concern clicking of the injectors due to the high pressure they operate under.  Ask to drive another 2.0 MKZ and see if it's "normal."

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  • 2 weeks later...

Sounds like BS to me.  I've had  several 2.0 service loaners and have never heard any knocking noise under the floor.  AFAIK, high pressure GDI pumps don't make knocking sounds.  Complaints about noise with these usually concern clicking of the injectors due to the high pressure they operate under.  Ask to drive another 2.0 MKZ and see if it's "normal."

 

Total BS...

 

I don't know about anyone here, but I've NEVER met a New Car Dealer Service Department that I've liked.

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I haven't been to a dealer service department in many years due to high cost and poor service, but my Z has 4000 miles on it and I'll be taking it to Carman Ford/Lincoln in New Castle DE when it hits 7500 and thereafter.

 

Have you heard the knocking noise described above?

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  • 5 months later...

I have noticed the noise on my 2017 MKZ 3.0T I actually noticed it when I picked up the car and the salesman noticed it too. We could not figure out what it was but I have not noticed the noise since?

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  • 1 year later...

was about to pick a new to me used 2017 mkz 2.o awd when I noticed the rhythmic thumping from under the driver  side rear floor. was about 120 hz, seemed most like exhaust leak, turbo, egr, cat, or vibrating muffler. I put purchase on hold and dealer is going to investigate. has anyone found answers to this noise? thanks

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Follow-up post...almost 2 years later...

 

I’ve only heard the noise twice myself, my wife is the primary driver. The 1st time was at the dealer the day we picked-up the car. The 2nd was in my driveway the day I posted on this blog. My wife heard the noise a 3rd time as well around the same date. Bottom-line is that our experience with the car has been very positive all-things-considered. No regrets...

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I think I discovered the source of the sound!

While crawling around under the back end, I discovered two holes in the bottom of the muffler. both were dripping water and were surrounded by oxidation and scale from road salt. when I held my finger softly under the holes the rhythmic puffing/thumping sound was duplicated.

spoke with dealer about replacing muffler, but when we researched the part, turns out the two holes are there on purpose, not due to rust. 

So I bought it! Got a price that made me smile and had a super smooth ride home. Already have the Lincoln Way app starting the MKZ remotely. 

Have fun and be mellow!

20190914_133531.jpg

Edited by villac
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  • 1 year later...

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