Interesting problems, solutions
 

I just want to share with you guys the problems and solutions I had with my M103 powered W126 recently:


1. Oil pressure wouldn't go above 2.5 bar and at idle would sometimes drop to 0

So I thought to myself - a bad sender so I drove like this for about 800 miles

Changed the oil and filter and BAM! oil pressure back to 3 at cold idle and never goes below 1.5 bar

so my question is - was it a clogged filter causing this? and if yes then why did the bypass valve not open? filter was MANN (I did about 3k miles on it)



2. Grinding noise at low speed coming from left rear

so I took the wheel off, took the caliper off and with the car in neutral I COULD NOT TURN THE DISC WITH MY HANDS.

I had to put in 2 lug bolts and with a steel rod for leverage I was able to turn it and even then it was a struggle.

So off came the rotor which I installed less than 2 years and 25k miles ago.

Inside there was so much rust flakes and dust that it was binding the parking brake shoes with the disc. I set the parking brake properly and it was rotating freely last time I did the job. Rotors were not the cheapest either.

I guess it's just the northeastern salt and moisture that did it

Bad oil pressure senders are a common issue, especially if original. Oil/Filter change drained all the oil out of the canister and sender. You'll have issues with it again. My SDL was intermittently flaky for 6+ months before it finally wouldn't rise above 1.5bar under any circumstance.

Same here. It used to fall to almost zero on my 300SD at warm idle and would bounce around until I changed out the sender, then it was perfect again.


And yes northern climate will destroy rotors/parking brakes over time, the newer cars have heavily coated rotors that helps minimize this but the older ones did not.