leaking tandem pump

I have spent a little time searching the forums for any info on the MKV tandem pump but haven't been to sucessful.

does anyone know if a leaking tandem pump difficult or expensive to fix? and what exactly does the tandem pump do?

im hoping to find out some info before I have to take it to the dealer to get it fixed. Dont wanna walk in there not knowing anything about it.


any info and help is greatly appreciated.

!/2 the tandem pump supplies intermediate fuel pressure to the injectors and the other half makes vacuum for the brake booster etc. they are not timed to the engine like an injector pump on older engines are.

It is possible for a tandem pump to leak fuel into the valve cover, so check your oil level frequently till you get the pump fixed. Bentleys cautions that internal leakage must absolutely be checked between the fuel and oil sides of the pump if it is re-installed. If for some reason the dealer is able to repair your pump, (they probably will replace it) and re-use it, make sure they do the internal leak test.

thank you for the info.

I know its leaking externaling because I had to replace a coolant hose it leaked on and caused to swell and rupture. Not sure if the external leak is coming from an internal leak yet.

Any ideas on what may cause this pump to leak?

tandem pump

Ok you have an 06 Jetta. Put that in your signature or in your post. Always give model, transmission, year ect when asking questions. In 04 there was a recall of tandem fuel pumps on certain models according to VIN. It was an external leak. Internal leaks will give you a higher oil level reading due to diesel entering your engine & ending up in the oil! It will also dilute your oil resulting in damage if not fixed!