I have a 2001 duramax and have recently changed the fuel filter. When finished, I primed the fuel system and started the engine. The priming pump plunger is leaking diesel fuel by slowly. I have determined the o ring to be the problem as it is swollen and out of shape. I called my local GMC parts counter and asked for a replacement but was told that none was available and that a new priming pump was the only fix at a cost of $700.00. Does anyone know of the size of the o ring that seals the plunger assembly or a part number that would identify a compatable o ring. The thought of having to pay $700.00 for new pump when all that is needed is an o ring makes me a little bummed.

you might be able to find one used on ebay..

You could try measuring the old o-ring and then look for an equivalent replacement...

Here are a few websites to check ...

http://www.oringswest.com/

http://www.allorings.com/size_cross_reference_framed.htm

:)

SOLIDMX, check out this photo and tell me if this is the seal you are talking about. Later! Frank
http://pg.photos.yahoo.com/ph/fnsblum2004/detail?.dir=1466&.dnm=8ca1.jpg&.src=ph