W212 - Loud metallic screeching sound

[derektrotter]

Hi All

Have a W212 E250 with 50k miles, while driving yesterday from the front end I heard a very loud metallic grinding/screeching sound, it went on for 2-3min (was trying to find a place to pull over), just before I pulled over the sound dissapeared, since then i've done 30-50 miles with no issue.

I had opened the bonnet to check the oil for the very first time since I've had the car earlier on in the day, then this happened but I think its just a coincidence..

Any ideas of what to check? been doing some research and it may be that a stone was stuck in the disc brakes which worked itself loose, just slightly paranoid I may have lost some sort of metal shield underneath the car that i'm not aware of.

Thanks

 

[optimusprime]

Derek i was just about to tell you about the stone that get in the rear of disc and the back plate but you know about it . I think it will be like , use it as normal , if it shows up again then you will need to do more checking .I have been told about the aircon pump going bad this makes a noise like it .

 

[derektrotter]

Ah, thanks for the reply, aircon was turned off (normally have mine set to manual) so its looking more like the stone theory, I'll see how it goes.

 

[grober]

Almost certainly a trapped stone- very alarming sound. Best and cheapest test for now- wait and see- if it doesn't come back- then you will know that's what it was.

 

[derektrotter]

It was very alarming, never had it before, I've searched on youtube and the sound seems to match the stone sound.

 

[optimusprime]

Aircon pump is still in rotation , even if its not switched on .See how things go in future.