Hi, I'm new to this forum and would appreciate some help with a new mechanical issue........

[Zenith555]

My W211 2007 320CDI has a speed sensor issue on right front wheel - diagnosed with icarsoft scan tool. Also noticed that power steering has become heavy at low speeds. Did not realise that the car must have speed sensitive power steering? I just bought it in August this year for my wife so she can take her elderly father to appointments etc with his wheelchair in the boot. Have booked the car into local garage to have speed sensor checked/replaced. The only thing I am worried about is that intermittently on full lock, the power steering screeches. Sounds bad/damaging. Can anyone tell me what causes the screeching and what should be done about it? Any advice would be greatly appreciated.

 

[Blobcat]

Hello and welcome,

The sound is the pump straining, you shouldn’t hold any car on full lock for any length of time as it damages the pump.

 

[SmartAmg]

Welcome.

 

[Uncle Benz]

Check the alternator pulley hasn’t seized. It’s a freewheeling type, and you get a lot of belt skip if it fails.

 

[dry run]

Welcome

 

[M80]

Check the level in the steering fluid reservoir.
But remember the level is dependant on temperature.

 

[Zenith555]

Thank you for the info. My car has been outside in -10C most of the week. Would this affect the fluid level?

 

[Zenith555]

Hello and welcome,

The sound is the pump straining, you shouldn’t hold any car on full lock for any length of time as it damages the pump.

Thank you for the welcome and advice. It was just manoeuvering in a tight carpark that I noticed this. It just happens occasionally but does not sound very healthy for the car.

 

[Zenith555]

Check the level in the steering fluid reservoir.
But remember the level is dependant on temperature.

Will do, thanks.

 

[Zenith555]

Welcome

Thank you - looking forward to using this forum to learn more about my new - old car. I've never had such an old car before. Seemed like a good idea at the time. It has been a pain with a lot of faults, some minor and a few not so minor but it's a lovely thing to drive and I prefer it to all the modern plastic cars eminating radiation from electric car batteries and wifi! Just need the air con fixed and wheels refurbed , then hopefully it will be ok and useable for a while. It's a 2007 with only 55k miles.

 

[Zenith555]

Welcome

Thank you!

 

[mioba]

Welcome to the forum - its rather satisfying correcting a new old car and doing it correctly.
A perfect running merc is a joy and you will redeem the fruits of your labour.
Make sure you use genuine merc parts for the sensor (a.o).
I wouldn't worry about the screech - its just the pressure - they all do it.

 

[PaulG]

Welcome to the forum. There is always lots of good W211 advice here.

 

[M80]

Thank you for the info. My car has been outside in -10C most of the week. Would this affect the fluid level?

Not if the level is correct.
It rises with expansion. So cold it could be a bit low, then they can groan some.
Yours is a screech, which is most likely the pump causing the belt to slip on the pulley, so my thinking your fluid may be low doesn't really fit.