I am wondering just how vital are these pumps to the drive ability to Mercedes? I have saw cars in the past where these things have been disconnected or completely removed, especially on the older cars, but still running fine.

The one on my MB has had the hose removed and the belt removed from it, so there is no pump operation, but my car still runs fine. I am wondering- would it run even better if a new one were in place and hooked up? Could this be part of my engine stalling when warm problem? I looked at my pump and it appears to be seized up. It will not turn. There is also something running out of it.

I know a new one is very costly - about $900, but I know where some good used ones are for a much better rate. Should I have one installed, or is my car not affected by this item not operating? It does not seem to affect the older cars, but I know these Mercedes are a horse of a different color and wondering if it is indeed an issue on these cars. I know that it basically sends "unburned" fuel back into the engine - or something like that?

They started putting these on some cars back in the mid to late 1960s (American cars) - especially the California models, then on more cars in the early 70s. My old 72' Buick Electra had one and luckily, it was still in perfect order.

Thanks again.