Hello JMH
Take it back to your MB only indy.
Sounds like they may not be installed correctly or you got a defective part.
Take the mechanic that will work on your car for a ride; so he will know exactly what you are talking about.
They may fix it under warranty.
Have a great day.

__________________
ASE Master Mechanic

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D

https://www.boldegoist.com/