Hi all: I have a 06 cooper s with 78,000 miles.

it is outfitted with alta 2% pulley and -15 % supercharger pulley.

exhaust smell is pure and runs nice and cool.

just did oil change and installed new timing change tensioner.

rattle starts at around 1800 rpm under load and starts to lessen around 3000 rpm. same if in either neutral or moving. it is hard to really determine where the rattle originates.

oil change did have minimal metal in filter...but oil change was after 8000 miles.

engine runs real strong. exhaust is extremely clean. there is no problem with engine temp.

rattle started while aggressively traversing rough mountain pass

I am thinking heat shields, exhaust hangers?

possibly supercharger? I don't know if the lubricant is dirty or how much is in the s/c. can the supercharger emit this rattle?

the alta pulley is not a 2 piece unit...anybody aware of problems with the alta or alta sc pullies?

serpentine belt tensioner or idler pulley?

So where would you go next to isolate and correct this problem?

Thanks, Mike

 

Start with the easy stuff. Belt, Belt tensioner, damper(gas strut on the belt tensioner), idler pulley. On my son's car, it was the damper that failed.

A stethoscope is also a handy tool to help diagnose the rattle.

 

Well first off, is the noise while stationary or while driving too? Is it isolated to the engine compartment, or is it under the car, rear of the car, etc?

You can look down into the belt drive area to inspect for problems, bushings in the tensioner shock being blown out or missing, the shock being failed internally, the tensioner itself being broken, the PTO gears of the SC being demolished, alternator, and also the Alta crank pulley slipping on the crank (which is fairly common).

Do you get any battery lights, loss of powersteering?

 

hi..thank you for responding. the noise occurs in neutral/not moving and while moving at 1800 to 3000 rpm. I pretty sure it is in engine compartment. Bushings on the tensioner shock seem okay...maybe internally it is wrecked. I am not getting any warning lights including battery and the temp of the engine is good so the water pump is working fine. Powersteering is good. We are going to start checking the pulleys and in this regard is there no key to stop the alta from slipping and is it possibly slipping because it is not torqued properly? If no luck here we will move onto the sc. Thanks for your response

 

Start by detensioning the belt and run the engine briefly. Does the noise go away?

You say it comes and goes with clutch engagement and disengagement, that would lead me to believe clutch or throw out bearing problems.

 

Try the timing chain tensioner. That causes a gnarly rattle.

 

hi...just to clarify noise does not occur in the engagement/disengagement of clutch...happens at 1800 to 3000 rpm when it is in either neutral or gear and there is increasing rpm. I have changed the timing belt tensioner and there is no improvement. I will take the belt of to see it we can get a better idea. thanks very much...mike

 

Edit: I'm at work and I missed that you mentioned that you replaced the timing chain tensioner in your original post, and was thrown off by your last reply that said "timing belt tensioner"...sorry for being annoying and throwing info you already knew at you.

To clarify, there are two tensioners that can rattle in the MINI:

1. Serpentine belt tensioner: Big assembly with damper that keeps your serpentine belt from slipping. Looks like this.
2. Timing chain tensioner: little pneumatic tensioner in the block that keeps your timing chain guide at proper tension. Looks like this.

 

rattle noise is quite a bit better with new chain tensioner but can hear the rattle off and on. So will keep working on getting rid of it completely.

I noticed that infrequently the engine is missing at higher rpms so any thoughts on that...fuel filter, plugs, timing chain??

Plus with the Alta 2% crank pulley and Alta -15% supercharger pulley what are the best plugs to run?

One last thing I just changed the oil and want to see if any metal is in the oil filter. Can the filter be taken off without draining the oil without any significant oil loss/mess? Thanks, Mike

 

You need to run a step colder plug with a reduction pulley: NGK Colder Plugs Just select the colder plug option in the drop down.

The oil filter will make a small mess if you just pull it out quickly, but if you loosen the filter cap enough that the o-ring seal is broken it'll allow the oil to bleed back into the engine and allow you to remove the filter & cap relatively cleanly.

As for the misfire; there's a whole slew of reasons you could be having those, best to start with a proper diagnostic.

 

Regarding your impression of missing at higher rpms, in my experience new plug wires frequently fix the problem, assuming that the coil pack and plugs are good.

 

Make sure you check the terminals on the coil pack itself for corrosion too!!

Terminal 3 is notorious for getting all rusty. Grab yourself a light-bristled wire brush from O'Reilly's and lightly brush that crap off your coil pack terminals!