Can too many enabled shaders cause crashes?

In short: I experience occasional crashes when killing enemies in hl2 but only when I have 2 or more heavy shaders enabled (for example ReflectiveBumpMapping + MXAO(with IL turned on))
So is there an issue with combination of certain shaders or is there some kind of resource limit?

Every shader uses a certain amount of texture memory on your GPU (some more, some less). The more you enable, the more memory is used. Your GPU only has a finite amount of VRAM, so eventually it will run out, which can lead to unstability (since the OS is forced to move the memory to normal RAM, which is slow to access for the GPU). This all depends on the resolution you are playing at (larger resolution = larger texture = memory memory required), your game settings (heaving settings like texture quality at "Ultra" will use memory memory) and which shaders you use.

Thanks for answering, lowering texture resolution seems to reduce the amount of crashes. However I was monitoring gpu memory and it had about 1.5gb left available and it wasn't spiking during the crashes.