How does somebody troubleshoot our struts if we have a internal problem in them since there a couple different stage for stiffness. Are they just looking for oil outside of the struts

 

If it's a leaking strut/shock, then there would be grease on the damper body.

 

i know that but what about internal leaks where it doesnt show in the outside

 

According to TMC, leaking to the level of the lower spring mount/seat is fine.
Does the shock absorber make any clunking noises on bump or rebound?

 

Yes the rear Do when i go over railroad tracks or speed bump

 

Push down quickly on one corner of your car, if it is relatively hard to push down and comes back quickly and smoothly without bouncing your shock is still in decent condition. Or when your driving down the road and go over a set of bumps or recessions the car should feel connected at every corner instead of feeling like each corner of the car is doing its own thing.

 

I did extremely heavy research on this back in my BMW days. To be specific, I wanted to find out the life of a damper. I reached out to an OEM and they told me the life expectancy of a damper is about 80,000 miles. Further, there is degradation over time, and the efficacy of a damper is not an on/off switch, this is what I think the OP is trying to ask. It's not totally about "bouncing your car" or "looking for oil," though those can be signs, they're not a tell-all.

Also depends on what type of car you're driving. If you're driving an ///M, AMG, F etc, then there should be more emphasis on replacing dampers sooner than later as top performance was what the car was designed for. 35,000-50,000 miles.

F Sport, sure replace them sooner too if you're picky. I'd say around 50,000-75,000 miles.

If driving a "normal" car where performance isn't really the car's primary characteristic, my vote would be to replace them when you experience abnormal tire wear, handling, or any other visual signs of failure like leaking oil. Or about 100,000 miles.

So there's no 100% on point answer other than to say, replace them when you feel it will serve you best to replace them for the type of car and the type of driving you do. And no that does not include when they're failing. Driving around with bad dampers is dangerous.

 

And BTW this goes for traditional damper design. when you start getting into aftermarket big name/big company heavy duty large diameter shafts, external tanks etc, the quality, price, and thus the lifespan goes up. this is just for factory stuff.

Bought a set of 12 year old Bilstein Sports back in the day which have extremely heavy duty monotube construction and they had 215,000 miles on them. hard as a rock. no noticeable loss in damping quality vs a new set which i had on another car.

 

If you have an Fsport, just change them. They cost nothing, the biggest cost is installation. I can get the front or rear 2 delivered + tax + customs duty to Australia for under $220 USD....no brainer. AVS shocks available from Rock Auto. Keep your prestige car pristine!