97 E320 RADIATOR FAN HITTING RADIATOR at the bottom.
 

Got the car about a month ago with no issues, 10 days ago a clicking and ticking sound would appear at start up for a few seconds. Today I found out it is the radiator fan making contact at the bottom with the radiator.

Any ideas why this happened?
How to diagnose and repair?

Thank you in advance

I had the same thing happen, and the previous owner thought it was the torque converter.

What is was, was the Motor Mounts were shot. The brown liquid in them had leaked and left all the oozing marks on the bottom of aluminum of the motor mounts..

Hope it helps,

Martin

Also check the fan clutch. This can happen when their bearings go bad.

I would diagnose the problem as bad motor mounts also. Inspect the clearance between each motor mount and the frame. If the motor mounts are original it would be a good idea to replace them. Recommend buying new motor mounts from a MB dealer. That's a job you don't want to repeat anytime soon due to inferior replacement parts.

See if the lower radiator support is bent. Happens all the time.

X2
 

Unfortunately,"Curbing" the W124 is a Weakness
Almost Any time you "Bump" a Curbstone with the front of the Chassis,the
Bottom radiator support is bent Upwards reducing the clearance between
the Radiator and Fan.

motor mounts

Thank you guys for the tips, ill crawl under it this weekend and check out all the noted possibilities.

Another possibility
 

On my 97 E320, the bottom mount of the radiator assembly is less than static, so a good bump on the bottom, like when parking, can push it back and has made the fan make contact before. It also caused the aux fan motor to rub the top of the front bumper. How I fixed it, sort of, is to just pull the bottom of the radiator back into place forward whenever that happens. I also put the aux fan assembly back on its bolts at the top (it attaches to the radiator) and shoved a tennis ball in there to keep tension on it.