Hey guys!

Back in January of this year, first time I heard the below noise when I was on the first traffic light after cold start. I thought that it comes from another car around me. Not always happening though and as a matter of fact, the noise was gone for 2 or 3 weeks. It is a continuous thump... When car is cold, the noise could be heard even if the shifter is in P position. When car is warm, the noise can be heard when in D, S or R and when I move shifter to P or N, noise disappears within a second or 2. Then I put shifter back to R or D and noise comes back.

I have checked exhaust and it seems stable, no rattle from it, but I didn't go under the car to check the whole thing.

The noise is present throughout the video pretty much, but from 6 seconds mark, it is louder: https://drive.google.com/open?id=1wE...nhHILRMPw0cQVh

I took the car to the dealer for other things and also asked them to see what this noise is about, but tech couldn't make it happen while diagnosing the car. He did see the video before looking into it.

 

I am still trying to figure out what this noise could be...

 

Possibly a torque converter going bad.

 

The car has only 25K miles and all maintenance was done by MINI for free. The transmission seems to be normal without any issues. I came out of the car and sat by the both rear wheels, listened... and I could hear that thump sound. It resonates to the back. I though that it is the exhaust that is failing. So is the thump usually an indication of malfunctioning torque converter?

 

Honestly I don't think I have ever heard a noise like that. I have never taken a Mini automatic transmission apart but if it's similar to a chevy transmission I'd be looking at the Torque converter or the transmission fluid pump. Just the fact that the noise goes away when you shift to P or N leads me to think transmission related but I could be completely wrong. You would think with that low mileage and all service work done it would be fine. Unfortunately it is a mechanical thing and I have seen brand new parts out of the box that were bad.

 

I see. I tested yesterday a bit more and here is what I can add.
1) After I start a cold car, with the gear in P, it would take about few minutes and when the RPM normalize then the noise comes. It is pretty steady as it sounds in video. I can hear it inside the car or by rear wheels area which I discovered yesterday.
2) Now, while driving in D, I come to a stop at a red light. If I stay there for at least 15 sec, then noise most likely comes back. During driving nothing is heard.
3) I can only hear it while idling and if the noise isn't there, I can force it to come back by switching from D to S or R. So if I switched to S the RPM goes up a bit as usual and I just wait for few seconds(up to 10). I can hear the noise come up and is steady thump. When I switch back to D, I can hear the noise to become quiet a bit.
4) I can hear it in N as well but only if there is no noise outside(at night) as in N the sound is very faint.

Here is the additional video file which was taken back in April. In the video I am shifting through R, D, N
https://drive.google.com/open?id=1gY...3Az5fYmxHuI0KR

 

I've a nice new set of headphones, and that's pretty good audio. I noticed half way through that that revs stirred just a little, but enough for me to notice that the knock did NOT change when the revs came up. On replay it sounded that way also.

Would you agree that the knock is independent of engine speed?

Cheers,

Charlie

 

Yes, I did try to rev engine a bit to see if the thump/knock sound changes, it didn't. Yesterday though I gave it a bit more gas around 2K or a bit more and sound of the knock changed but I don't know if the engine sound was louder than the knock and absorbed it. I will re-test again and will shoot another video.

 

Created few more videos:

1) Car is in D and creeping forward: https://drive.google.com/open?id=1ue...9bMYpqN-6OKCSx
2) Car is in different shifter positions: https://drive.google.com/open?id=108...l6lhDLYT-xZUo-
3) At 50 sec. mark, some acceleration at idle is applied and to me the noise is still there : https://drive.google.com/open?id=1lN...uFaxfZJrbIC419

 

I have a f56 manual and have had the same noise but significantly quieter most of the time for a few years now. Every time ive taken it in they could never reproduce the noise. I think it is the exhaust banging on something under the car, maybe misaligned. When im in neutral it is a light tapping that seems in sync with the exhaust pulses out of the tail pipe and the light engine vibration I feel in the cabin. Leading me to believe it is something to do with the engine moving in the bay. When i put it in gear and start to slip the clutch the noise will increase to a similar level to your vids. It goes away pretty much after i start moving but will hear it if i lug the engine when accelerating. With you having a Auto, when you put it in drive it does put the engine under some stress and probably increases the noise similar to when I slip my clutch to accelerate. I also saw you had your engine mounts replaced recently which may have caused the exhaust to get misaligned. Either from the excess play in the engine caused my the failed motor mount or when the mount was installed. hope this helps

 

Thank you for the info/your story. The noise started in January this year. The lower and upper engine mounts and transmission mount were services this month. Looking back into January, my car was in the service at MINI because of the clunking noise at the rear. So the tech didn't know what it was exactly and possibly was diagnosing where the sound was coming from. The dealership decided to order new rear shocks to see if it will help. First they ordered a wrong shock as mine has dynamic dampers... When the ordered part arrived tech remove right rear shock from my car, then realized that wrong part was orders. So he put back my original shock and ordered the correct one. I took the car back while we were waiting for rear shocks from Germany. The next day I was at a stop light and heard that thumping noise the first time :(

I do know that tech played with rear stabilizer bar and end links. Since end links are not Right or Left side specific, when installing, the tech installed right one on the left side and left one went to the right side. I don't know is that could of done anything...

I think one of the muffler rubber hangers could be the culprit for the sound. I put my car in P and came out to the back. Put my hand over that rubber hanger that is towards the end of left rear and did feel more vibration then on any other surface of the muffler. I was alone, didn't have anyone to put car into D while I check. I can't get to the second rubber hanger without jacking up the car, as it is further under the car, so don't have any info on that. I did put camera under the car and see that when I went through some of the gears(R, D and S), at one point that rear rubber hanger moved forward a bit under some tension.

The 2 metal hooks are not 100% aligned one under the other. Does it look similar(hanger and hook) on your car?

 

Some update on the issue. I was suspecting the noise being there when the gas tank is full. Since Tuesday my car had half or less of fuel in the gas tank and I couldn't repro the issue as it was gone. I thought the noise fixed itself. Today before filling it up, I thought "hope the noise won't return. Once I filled the gas tank, the noise did come back.

 

I checked under my car and everything looks fine. I wigged the exhaust as much as i could and it doesn't seem to be hitting on anything and rubber mounts look in good shape. Thats very interesting about the gas tank being full and the knocking coming back. Ill have to check next time i fill up and see if mine returns also cuz once I posted that i had a similar noise it hasn't happened since. Pretty sure im still on the same tank cuz i haven't been going many places.

I also realized my license plate is only held on by 2 screws in the top and the mount is kinda loose feeling. Ill prob get 4 new bolts and check out if i can secure the mount better and see if anything changes.

 

I was doing more research: first cleaned K&N filter a bit few days ago and yesterday changed back to stock air filter and looked in the engine compartment. Little by little, the noise slowly traveled from rear of the car to possibly the front of the car. Seems that engine's vibration rhythm changed by doing few things above and may not be resonating though the exhaust or another part as it did before. Now when turn on AC, the faint thump/knock is coming from engine compartment. I shoot a video(link below) where I point to the pipe or tube that resembles that thump/knock feeling. You can possibly hear that engine noise changes a bit to a calm at 1:45/46 min mark

https://drive.google.com/drive/folde...Z_?usp=sharing

 

Another possible discovery. So in the above post and video, that thing seems to be fuel tank vent valve. Since there are no error codes displayed and 2 hoses are vibrating/pulsating intermittently, I think the issue could be somewhere there. Anyone has issues or symptoms of failing vent valve or possible vacuum leak anywhere in that area?

 

Can anyone with possibly F56 or F55 MINI COOPER S(preferable 2016 model) check MAF sensor g/s readings at warm idle for comparison? I just want to see if your MAF is giving better g/s readings than mine at idle.

I used Bluetooth scan tool to read and capture live data. I took another phone and recorded a short video as well. In the video the car was idling and the app showed MAF to dip below 2.0 g/s and Oxygen Sensor Current (B1-S1) went into the negative. As I understand the range for O2 is 0.1 to 0.9 mA.

Here is the video link, maybe it will be enough to see if there is an issue:

https://drive.google.com/drive/folders/1f4jrOimx4A4SjzOU_1fdq-9K3qkqTjgd?usp=sharing

Another link to live data while driving for ~15 or so minutes. Just pick what you are interested in and see numbers or make a graph. This data has STFT/LTFT Bank 1 info as well as many others.
http://aws.ithinkcar.com/Home/Index/shareReport/diagnose_record_id/5e3c38a5f73btZnR/report_type/4