Engine whine - Turbo?

[Budgie1]

Hi. I have recently become more aware of a noise from my 2003 Sl600. Haven't had the car long so it may have been there from when I purchased it. Hoping some members may be able to put my mind at rest

When accelerating or on a positive throttle there is a whine seemingly from the engine compartment. Happens around 2000-2500rpm. I can hear a similar sound when revving the engine in neutral or park at the above engine speeds.

I am hoping this is a normal sound from the turbos kicking in. In higher gears the sound is not really audible, generally the revs are lower at cruising speed.

The noise is different from the normal engine sound - if you are hard on the throttle the engine noise gets more intense and drowns out the whine.

Thanks

 

[EDZ649]

Definately sounds like the turbo's to me.

 

[Budgie1]

Definately sounds like the turbo's to me.

Would a whine be a typical turbo noise on the 600, or might it indicate bearing issues

 

[biturbo]

The resident s600 turbo man is here.
13 weeks of turbo troubles and research has brought me a wealth of knowledge. I hope what i have found might help.

If its a whine its not the bearings as someone suggested. They make a terrible racket, sound like horses hoofs. If the whine is coming from the turbos then its air leaking etc, could be wastegate, pipes etc.

Whine on these cars are normally down to 3 things.
ABC resonating
Torque converter
Turbo leaking.
turbo kicks in at 1.8rpm on these biturbos.

What mileage have you got on it?

If its in neutral and you can hear it i think its the turbos. It does make a whoosing noise from the outside but thats the air escaping from the wastegate more so in neutral, if you have it when driving then excess air is escaping somewhere, you need to get someone to check it.
No fault codes come on for problems with turbos. Warning.

 

[Budgie1]

Many thanks, I will run a few tests tonight to identify the noise a bit further. If I park up in neutral should I be able to identify air leaks with the bonnet up ie determine where the sound is coming from.

The performance of the car still feels very strong although I suppose if the problem existed at purchase I have no comparison. Damm frightening if the thing isn't running on full power!

For the other 2 potential issues, ABC & torque convertor is there any way to identify or should I leave it to the wrench.

Cheers.

 

[Budgie1]

I noticed that the whine is considerably louder when the engine is cold. My morning commute is around 10 miles, towards the end of the journey the whine is much quieter although still audible around 2500rpm.

Googling "turbo whine when cold" shows alot of drivers experience this although I haven't yet determined whether it presents a mechanical problem yet

 

[cazyp]

I noticed that the whine is considerably louder when the engine is cold. My morning commute is around 10 miles, towards the end of the journey the whine is much quieter although still audible around 2500rpm.

Googling "turbo whine when cold" shows alot of drivers experience this although I haven't yet determined whether it presents a mechanical problem yet

Have you had a listen around the turbo pipes while someone revs it?
Could it be gearbox related rather than turbo..? Esp as louder when cold?

 

[biturbo]

mmmm, sounds more like ABC as that whinnes when cold and when the fluid warms up it goes quieter.

 

[Budgie1]

mmmm, sounds more like ABC as that whinnes when cold and when the fluid warms up it goes quieter.

There was a leak in the ABC and I got the dash warning light. When I took it to the garage I don't think there was much fluid left in the system, a leak from a jubilee clip the culprit. I now check the level regularly but wonder whether the noise is coming from the ABC / PS pump. Expensive??
The noise varies with revs would this be consistent with ABC pump.
Given the noise gets quieter I wonder is there risk of further damage if I don't do anything.

 

[biturbo]

go get it checked asap.
ABC system is expensive
£900 for pump, £550 for valve.

ABC fluid is highly pressurized, if you have had leaking etc it basically puts extra strain on the various bits of the abc system, pump, valve and pipes.
You need to drain whole system and put back the fluid levels, its not a low maintance type fluid system.

 

[BlackC55]

It is also worth checking the pulleys on the V belt. Pop the belt off and start it and see if it has gone.

 

[biturbo]

Got get it checked.
ABC fluid is very sensitive, or should i say highly pressured and can cause problems along the route, pump, valve or pipes when levels are low.
The pump etc and pipes can make a whine noise.
Pump is £900 and valve is £500.
Apparently you have to drain whole system and then fill it all back up, not just top it up.
Like i said its expensive id get it looked at.
From your symptoms id look at abc first.

 

[ringway]

It is also worth checking the pulleys on the V belt. Pop the belt off and start it and see if it has gone.

I was going to suggest that.

My Sprinter had a whining noise for months and I couldn't find where it came from. Replaced the alternator...

It turned out to be the idler pulley which I replaced a few weeks ago after it disintegrated.

Spot the difference?



Does the whining noise follow the revs pattern up and down?

The noise on my Sprinter was audible on acceleration and deceleration and also in neutral. As Olly says, slip the belt off and have a listen.

If it is the idler you may consider changing the other (plastic) pulleys at the same time.

 

[BlackC55]

My advice is start with the basics first. Pulleys, pumps and turbos etc can all cause a whine.

Pin-point it to see if it is one of the ancilleries causing the noise first by removing the belt and starting the engine. If the noise has gone thne you know it will be an item that is powered by the V belt.

 

[Budgie1]

Many thanks to all for some great suggestions.

I'm going to be on holiday for a week (first ever skiing holiday) so assuming I'm back in 1 piece I will take the V belt off and test. I've just ordered a manual on the car showing how to take it apart and put back together so it might come in handy.

Next project is to fit an Alpine KCE425i unit I bought to display the iPod on the screen. Might try to combine this with upgrading the TV tuner to a basic ditial one.

 

[W220alter]

It was the ABC pump

I had a strong whine in the car, specifically when cold, and its pitch was rev-dependent. It was stronger up to 3000 revs and it was drowned out at higher revs. When revving up to 2500 revs and then taking the foot off the accelerator it even caused a vibration (reverb) somewhere. It went away completely when I was forced to replace the ABC pump (at €1850 incl. VAT - after a leak occurred) and the drive is now much quieter. I had earlier already replaced all pulleys and bearings.

Interestingly, now I hear a whistle when I put load on the car (accelerate medium to fast). Its pitch is higher than the revs (example: at 2000 revs I would expect a 2000 Hz whistle, but it is higher than 2KHz). The whistle does not occur when idling along on a road.

I think it is the turbos. Is this healthy? I just have not heard this whistle before - over the noise from the ABC pump.

Before I finish let me tell you that I had to replace the left ignition coils (at €1450 incl VAT). They broke when the mechanic washed away the hydraulic fluid from the engine after replacing the ABC pump. I had a misfire on cylinders 7 and 9. Don’t tell me this can be caused by faults in the other ignition coil bank!

 

[savinda92]

Is there a leak in ur air inlet or exhaust outlet paths? Coz mercedes doesnt let that whistle noise from turbos occurs. Noise dampers are there to absorb that sound.