Wiper blade/&humming noise/engine pings on RON 91

[newMercowner69]

Werner/Wilhelm's arm (wiper arm&blade),
Gets stuck when operated
The blade itself has come out too far,
Now it makes a loud humming noise,
When I switch/turn the wipers on. Also even though my owners manual states recommend RON is 91,
Lately over 2-3 weeks it pings,
Switched to United 98,
No pinging,
Strange, unusual &weird?.

[Chai]

Regarding the engine pinging using RON91, try changing your petrol supplier and see if it makes a difference.
If not cured regardless of supplier, you can: de-tune the engine further, or use 95, or a cocktail of 91 and 98.

Chai

[newMercowner69]

United 98 premium fixed&solved the pinging drama , issue &problem,
But now when I turn the Key in the ignition,
A loud humming noise comes thru the dash,
But disappears when engine is running &coasting,
Could this etc be electric fuel pump or wiper motor noise,
Even though wiper's not engaged?.

[John Green]

The mechanisum inside the wiper arm on these has to be cleaned and lubicated every few years to stop them from siezing and eventually breaking, yours maybe too late.

petrol is like wine and a few other things. You get what you pay for. I wouldn't put 91 in a lawnmower, its cheap nasty stuff....

[newMercowner69]

The humming noise i suspect may etc be wiper motor?,
It disaapears once engine's running,
Only happens/occurs after engine's started or ignition is switch to auxilary.

[newMercowner69]

Now appears &seems wipers DON'T&WON'T come on when switch is activated/engaged/turned on,
I'll check the fuses but diagnosing &suspecting wiper motor,
Who supplies Benz as O E. wiper motor manufacturer &supplier?,
Is it : Febi-Bilstein or Bosch/Valeo?.