89 560 sel

I got a few problems with my 1989 560 SEL, 98,000 miles. My auxillary fan seems to kick in whenever my temperature needle hits the middle. Sometimes, after my car has cooled down from a drive, i will start up the car, without kicking in the ignition, and the auxillary fan will come on spinning. I understand the auxillary fan should turn on when the engine gets very hot, however, it shouldn't be hot enough but it comes on, even during winter time. My mechanic says it could be the relay, which he checked and said it wasn't. he can't seem to figure it out. I replaced the radiator already. Any solutions?

also, the back seems to sag a little, or in other words, is lower than the front by quite a bit that you can realize it. i replaced the rear shocks and hydraulics since it was giving me a very bouncy ride in the rear. the back is still sagging a little bit lower than it should be. my mechanic says that changing the springs isn't going to make it higher in the rear to even up with the front. he also says that it's very difficult to change the rear springs on that car because he has to remove the differentiator. should i invest in changing the rear springs? it cost me quite a bit of money changing the shocks and hydraulics, i'm guessing the old springs in there is going to wear out the expensive shocks and hydraulics a lot faster. any ideas?


one more question, when i park my car, stop it at a parking spot, and put the gear in P, my car rolls back quite noticeably. any fixes for that?
also, do i need an alignment done after changing those shocks and hydraulics?