I am about to replace the timing chain/tensioner and rails on my 92 400 E in 2 weeks, I have collected all the parts I need.
Unfortunately the new tensioner is not OEM, it was made by a Germany company, the brand is "SWAG". Is this the infamous aftermarket tensioners you had used? If this is the case, I'd better order one from MB.
99 BMW 540i 6-speed 110K Km
03 SAAB 9-5 wagon 80K Km
92 400E (Sold) 245K km
Still missing the days with the Benz, it kept me busy.