albertchampion

hadn't driven it in a couple of days. this morning, on a short 15 mile drive, i heard a loud whining noise. thought it might be the a/c or on the radio. not.

exiting the car, the whine was coming from the engine compartment. and it did not stop with the engine off.

i opened the hood and could only discern that the noise was coming from the right front of the engine compartment.

5 minutes later, the whine had stopped.

returning to my garage, while driving, i heard no similar noise. but exiting the car, there was a higher pitched whine from the right front. and it took an hour for it to stop with the engine off and the car locked.

i am leaving town for a couple of weeks, so i am tempted to just let the car sit for a while. on the other hand, perhaps it should go see a doctor. and if so, should it be driven there? or towed?

car is under m-b pov warranty.

your thoughts would be welcomed.

BlownV8

Could be a bad idler pulley. If it goes, you will be stranded in a very short time.

biker349

i'd check the electric fan. it will run after shut down if engine is hot.

albertchampion

that the whining went on for over an hour after engine shut-down, informs me that those suspicions miss the mark.

at first, i thought it might be the lysholm compressor continuing to run. but no belts were moving. and the noise was being emitted on the right front, essentially adjacent to the wheel well.

a tow to the dealer?

or a drive?

that is the question.

BlownV8

I missed the part about it running after the car is off. The idler pulley would not be the cause of those symptoms. If it is not the fan, it might be possible that the intercooler pump is still running? Best way is to get a mechanic's stethescope and start listening for the noise.

albertchampion

now, you have identified the culprit that i suspect. and am i correct that this is an electrically powered pump?

because is essentially the location from which the noise is emanating.

no check engine or other warning lights come on by the way. and the car seems to run just fine.

i didn't put the car in the garage upon returning home. i figured if something was going to blow up it would be better for it to blow up in the driveway. 15 minutes after the noise had stopped[after more or less an hour], i fired it up and put it in the garage. no similar noise on running at low, unboosted rpms or after shut-down.

Becks Imports

I think the pump is not only electric but can be set to run continously, after the engine is off for set period of time, etc. That seems like the highest odds in looking for the culprit.

albertchampion

so, then tell me, why would this just start today? why not on friday when i was driving it? or on thursday? or wednesday?

not to be hostile, but i have to think that some component[s] decided to malfunction on sunday morning, 25/10/11.

saintz

The IC pump is notorious for going bad. It is in the location you mention, it runs after the engine shuts off, and the rotor can break, which would cause weird noises.

albertchampion

my dealer mechanic thinks that to be the problem as well. and advised not to drive it in for repair. it was picked up for a flatbed tow under my cpo warranty.

when i hear from him tomorrow, i shall report his finding[s].

saintz

Wow, never go to that dealer unless you're under warranty. There is no reason to not drive it. Most supercharged cars have a bad IC pump and don't even know it.

albertchampion

well, i would say this to you. this cl55 is under a m-b cpo warranty. it is my observation that when the vp of service, whom i have known for 34 years, recommends that the car be towed in, i pay attention. especially when the dealership is 100 miles via highspeed highways from my residence and the ambient temp in metro houston at the moment is close to 100F.

i should have thought to make a movie, with sound, of the car and the noise so that there would be no mystery.

i have driven lots of benzes, and other vehicles, over the years, and i have never heard anything like this noise before. especially one that went on for almost 90 minutes with the engine off.

i also care to say that my vehicles are all impeccably maintained because i drive them fast.

for my older benzes, i used to use an indy mechanic. but as he has aged, his shop is no longer up to snuff. tony at m-b sugarland may be one of the best benz wrenches in the usa. he has all the tools. and i have known all the service personnel at this store for decades. i would rank it the best benz shop in texas.

albertchampion

AIR INJECTION PUMP.

240M3SRT

Thanks for updating us with the culprit. I will keep this in mind.