I recently bought a high-mileage 03 MCS (145K miles) I've put 1000 miles on it now, it hasn't fallen apart, and I'm considering some conservative mods. But before I start sinking money and time into this project I want to try to get some sort of objective assessment of the engine. I figured a compression test is cheap, easy, and should give me some useful information.

Per the Benley manual, "Performing a compression test may cause a fault to set in the ECM and may illuminate the Malfunction Indicator Light (MIL). The light can only be turned out using either BMW special services scan tool or equivalent."

Does anyone know if this is indeed the case with a 2003 MCS (i.e. will it throw a code?) Also, I've been toying with getting an OBD scanner. Is there one out there that will reset codes on the R53?

Thanks.

Tom

 

Pulling the plugs and cranking the engine will probably throw codes. Get an OBDII scanner, something in the $60 and up range to be really useful. Run your compression tests (wet and dry), then clear the codes with the scanner.

 

Thanks. Actron CP9145 found on sale at Amazon is on the way. I'll hold off on the compression testing till it's here.