doltmo

Is it normal to hear a whining/growling sound from the V8K engine for a few seconds after starting a cold engine? If I had to guess, it sounds like a lack of lubrication. After about 5 seconds it goes away - at about the same time the idle speed drops. When the engine is warm, this doesn't seem to happen.

This is on a brand new '05 SL55. My '04 SL500 made no such noise.

Is this normal?

blueSL

That's probably the compressor that you paid all that extra money for making itself heard...

IanSL55

I have the same thing and have 'heard' that it's normal... As chance would have it, I'm taking it into the dealership tomorrow for my pre-3000 mile checkup... I will ask the tech about it...

~ Ian

doltmo

Let me know what you find out. I'm only 260 miles into the first 1000/3000 checkup. If this is something abnormal, I'll take it in earlier.

Kar don

that is the air injection pump making noise for the first few seconds of startup.

doltmo

Did my '04 SL500 have the same air injection pump - or is this something unique to the V8K's?

It sounds like there's someone under the hood trying to cut a wet 2-by-4 using an old circular saw with worn out bearings - after 10 seconds it fades out and goes away.

If I turn the car off, wait a few seconds and start it again - I get none of this noise at all. Strange. You would think the air injection pump would come on every time the engine is started.

IanSL55

Just back with my car... 2500 miles. The tech said it's NORMAL on a cold start... and even had one of the sales guys fire a cold 55 that was on the lot. Same noise... though it sounds a lot worse in my enclosed garage in the morning.

~ Ian

awiner

It's not the air pump. It is the Kompressor clutch/pulley. I have the same sound. Lasts for about 10 seconds at cold start.

Chris 45971

The saw analogy is a good one. I get this sound on cold start ups with my 500 as well.

awiner

If you are hearing a "Saw" sound, it probably is your air pump going bad.

Eventually if it burns out you will smell it.

Chris 45971

Yeah, the sound is like a mix of between a miniture table saw (you know with the round blade) and a small vaccume cleaner. The sound is muffled and not harsh. It only happens when I start the car on cold mornings. After the car's been going for a few minutes, I don't hear it again. I believe that this sound is the same sound that everyone else is talking about. This is not normal?

Thanks for the heads up Awiner.

Chris 45971

and it only lasts for approximately 10 seconds.

doltmo

Chris' description of the noise he is hearing from his '500 is dead-on with what I'm hearing from the '55. I didn't think my '500 did the same, but I've been without it for the past 8 weeks waiting for the new '55 to arrive.

So it looks like the noise is from the air injection pump - and it's not uncommon (they all do that?). At some point I'd like to understand why the air pump makes this noise - like lack of lubrication, about to fail, etc.

Thanks to all who responded.

cls55

hi
the noise you hear on start up is your power steering pump and thats normal.good luck with your car.

awiner

LMAO... We have now 3 possible noises. I know what all 3 noises sound like and it is hard to explain over a forum which is which.

The "SAW" type noise is definitely the centrifugal air pump however.