Cars been running great since I solved all the intake sensor issues but recently I've started hearing a chattering sound (similar to the traction control noise) happening under hard acceleration in the 2500-3500RPM range.

It sounds like its coming from the right side of the engine bay (drivers side) and it's hard to reproduce to get a recording. There is a slight hesitation when this happens but it only lasts for 2-3 seconds. At first I thought it was actually spinning the tires and causing the traction control to kick in, but I've switched to my summer tires and it's still happening, but less frequently.

Looking at the Bentley manual I was considering checking the timing chain, but that it on the other side of the engine from where the sound is coming from.

Thoughts?

 

Waste gate rattle ? You need to have someone rev the engine setting still and listen near the turbo.

 

I'll try that this weekend, but I've never heard this sound when the engine isn't under load.

If it was a knock, would the ECU throw a code?

 

Its its mechanical and something is rattling outside the engine, most of the time no CEL. Like a loose bolt kind of thought, its not connected to the ecu.

 

When was the last time you had an oil change? I was having a chattering sound under acceleration and thought it may have been the vanos/timing chain but it was just low on oil. Check the oil (which is hard as hell to read!) since it may just need half to a full quart.

I get the same sound every 3-4 months but it always goes away when I top off the oil.

 

1. Check your oil level

2. Is the noise maker properly clipped into the bulkhead? If it isn't clipped in it will rattle.

3. Air filter box? Is that properly fitted to the grommets and screw tight?

4. You may have a worn vacuum pump, when they wear they can create a clattering sound.

 

Thanks for the replies nkfry and WarEagle...

I was thinking something oil related but my oil level was on the low end of the range, but not below the bottom line. It had been about 4 months and 5000 miles since my last change at the dealer (Castrol 5w30). About two weeks ago I change the oil and used Mobile 0w40 (which is what I always use when I do it myself). I filled the oil to just below the upper line and the problem has completely vanished.

I could be brainwashed by Mobile's advertisements, but the car always seems to run better on their oil. Since the oil change the car has been an absolute beast, tons of torque with instance throttle response.

If it was the oil, I'm slightly worried I might have hurt the engine as this was going on for a little while and I never bothered to turn the Manic tune back to stock mode.

To address nkfry's suggestions, I have the WMW noisemaker delete, so no vibration there. I also have an NM intake so the air filter box is gone. I checked all the bolts and screws in the engine bay and nothing was loose so I don't think it was that.

The question about a worn vacuum pump is intriguing. Is that something that slowly fails and intermittently cause a clatter under heavy load? Or is that the sorta thing that will fail all the sudden with a CEL?

 

Glad you got it fixed! I've had the same issue twice and adding oil resolved it both times. I spoke to my Mini dealer about it and they said the turbo N14 runs hot and despite Mini's efforts it looses up to a quart of oil every 5000 miles or so. They said nothing majorly wrong with the engine or rings, it just requires you to stay on top of the oil level. I still find it unnerving though that it can loose almost 25% of its oil that quickly.

 

The vacuum pump can make clattering noise either at idle or under revs, but is most commonly caused by low oil level or lack of proper oil changes. There is no CEL for a failing vacuum pump.

1 quart every 5k miles is lucky actually, we've got customers who are buying 5 extra quarts of oil when we do an oil service due to consumption issues.

 

5 extra quarts! I've never seen oil loss like that, maybe half a quart every 3000 miles.

You mention vacuum pump chattering could be caused by low oil, when the pump is in that state, will there be a loss of power? I ask because your comments sound really close to what I was experiencing.

 

The only way I could see a loss of power being created is due to the wastegate actuator not getting proper vacuum. You could measure vacuum creation at the brass fitting on the vacuum pump and see what kind of vacuum you're pulling.

 

MINI only officially considers oil consumption a problem if it is more than 1 quart every 750 miles. So just every 2 tanks of gas just throw a quart in there because its low! :eyeroll:

The vacuum pump can definitely be a cause of it, especially on an N14. Its really simple to replace, the part is just a bit pricy.