how can you tell if the shock are blown? is there way to check iT?

 

If the shocks are blown, you will notice oil that has leaked on the strut itself. When the seal is broken, oil will leak down the shaft and onto the strut body. It is usually faiurly noticeable. Also, you would notice more of a bouncy ride, unless you have cheap coilovers or something like that which bounce anyway.