Hey everyone,

I have an 03 c32, and it has 104000 miles. Only thing I needed to replace when I purchased a few months ago was idler pulley.

Supercharger made a weird noise on startups, and figured out breather hose was disconnected from driver side air duct after air filter housing.

Noise went away.

This has been going on since I bought the car, the car launches with esp off when I first step on it after it warms up. But sometimes when I hit the gas pedal, the supercharger doesnt engage. Previously right before when I bought the car, the supercharger pulley/clutch was replaced under warranty.

I am thinking it is the intercooler pump, but my question is, when it goes bad does it work intermittently resulting in the supercharger engaging intermittently, or will the supercharger not engage at all?

I checked the fuse for the pump as well and it is good.

Only things that come up on star computer, were I was running lean ( this was when breather hose was unplugged) and stepper motor fault.


I can get the oem mercedes pump new for $134, or do you guys recommend another pump? are the electrical connectors same as on the johnson pump and cm30?

I have no personal experience (I am rebuilding a wrecked 02 c32 and haven't engaged the s'charger yet) but consensus in the forum seems to be to go with the Johnson pump and separate the intercooler water circuit from the rest of the water system for better intercooling efficiency. Good luck.

I need wheels for my c32. Have any? Thanks

Yeah when my Johnson pump just went out it'd do the same thing. Work occasionally, but if you revved too high in first gear or tried to launch the supercharger would cut out. I'd recommend the Johnson cm30 pump that basically everyone is running on here....they're like 150 shipped on some websites....pretty easy install if you have a jack too. I'm sure there's a DIY somewhere on here.

There's a recent DIY on here for the pump; Eurocharged sold me mine.

Intercooler Pump Replacement compliments of (1FASTC32)
https://mbworld.org/forums/c32-amg-c...placement.html

i would just start by replacing the oem pump with a johnson. Its not if the oem pump will go, its when pretty much.

I got a new oem bosch pump for $133. I'm having it installed tomorrow

Both the Johnson and Bosch will eventually die out from the electrical brushes wearing down. The Johnson seems to be a more reliable build though, and doesn't tend to fail early due to manufacturing defects, or failed electrical components. Interesting though that the Bosch pump is used very commonly on water to air intercooled applications whereas the Johnson is actually a marine pump not designed for high temperature use. Highly recommend separation of the intercooling system if used with a Johnson...