I have a 2003 STI which is due its 2nd cam belt change. I have been advised to change the oil pump as a preventative measure.

I have just bought a RCM oil pump which has 10mm rotors but after reading threads about AVCS cars having 11mm or 12mm pumps im not sure if i have bought the right one?

Can someone please confirm this before strip it all down and find out its wrong

Dan

 

changing the oil pump isn't a bad idea, as for the size i always thought it was a 11mm or 12mm pump although i cant confirm.

 

bump

 

Your pump if its the original one will be 10mm, so your replacing it with the same spec, this is more than enough to cope.

If you run a bigger capacity pump than your engine requires, all that happens is the prv is dumping the excess oil causing oil temp rises in the pump.

Most pump failure is caused by secondary debris getting into the prv & jamming it open causing pressure loss.