Tandem pump oil leak?

SPOOLIN_TDI

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Apr 16, 2013
Location
michigan
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2005 jetta tdi
Seems the back of my block on my pd bew is getting worse and worse. Iv been looking have at the tandem pump and I'm pretty sure its leaking oil behind it? Is this common? And where do I find Info on how to go about changing the seal? Thanks
 

Tdijarhead

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Nov 10, 2013
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Lawrenceville PA
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2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
Common yes, however it could also be the corner of the valve cover. Idparts has new tandem pump gaskets, as far as change out it’s pretty simple, I think there are only 3 bolts and the unit will pop off the end of the head.

You can leave all the lines attached. Just slip the new gasket in place and line up the pump with the end of the slot in the cam similar to the alh. Which shouldn’t be difficult because you don’t have to move anything.
 

oilhammer

Certified Volkswagen Nut & Vendor
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Dec 11, 2001
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outside St Louis, MO
TDI
There are just too many to list....
Often times it is the pump itself, not the gasket. But if you want to replace the gasket, clean it up and give it a try, it isn't especially difficult. Just use GOOD Allen bits, especially the 5mm ones.

I agree it could also be the valve cover, which can be regasketed on some versions, often these end up just needing a new valve cover assembly anyway. The new one will have Torx fasteners instead of the hex bolts.

Good time to examine the condition of the coolant vent hose assembly (the one that goes to and from the EGR cooler changeover valve, to the head, and upper radiator hose).
 

SPOOLIN_TDI

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Apr 16, 2013
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michigan
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2005 jetta tdi
I don't understand how the tandem pump has oil inside of it Are they fairly easy to fix if the pumpitself is leaking oil?
 

oilhammer

Certified Volkswagen Nut & Vendor
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Dec 11, 2001
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outside St Louis, MO
TDI
There are just too many to list....
Its insides are lubricated by oil. It has an oil feed going to it from the head. There is a seal between the vacuum pump portion, lubricated by oil, and the fuel pump portion, lubricated by fuel. That seal can leak oil, or the outer seal can leak fuel.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
There is no cam seal at the back end of the head.

If you are trying to narrow down an oil leak, get some UV dye and a light, add the dye to the oil, clean the area off thoroughly, then run the engine while watching with the light.

The only replaceable items that could leak oil in that area are the valve cover gasket (often requiring the valve cover itself, as I already mentioned), the tandem pump gasket, or the tandem pump itself. That's pretty much it. I doubt the cylinder head gasket would ever leak oil right there, I do not even think there are any oil passages at that end of the head. The end cam cap is a machined fit against the head itself, and is unlikely to leak any volume of oil unless it was off at some point and not put back on correctly.
 

gforce1108

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Aug 2, 2006
Location
Newburgh, NY
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04 Jetta GLS BEW, 14 Audi A7 V6 TDI, 13 Porsche Cayenne V6 TDI
Are you sure it's oil and not diesel fuel? They commonly leak and drip on the small coolant line that runs underneath it. Check that for signs of swelling. I didn't bother trying to reseal my tandem pump - I just bought a replacement from idparts. FYI - there was a recall on certain batches. Wouldn't hurt to check if yours somehow missed the recall.
 

Wilkins

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Aug 19, 2005
Location
British Columbia
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05 Jetta Wagon 5sp, 10 Sportwagen 6MT
Changing the gasket seemed to fix mine. Symptoms were pretty much what you describe. Cheap and fairly easy to do but take care as Oilhammer said. If it doesn’t want to fit back up make sure everything is aligned right, should fit up easily and perfectly.

One of two under hood repairs in 14 years that I would not classify as maintenance parts, the other being the EGR cooler flex pipe.
 
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Roger Carroll

New member
Joined
Nov 23, 2015
Location
Chillicothe Ill
TDI
2002 Jetta manual wagon
My 2006 Passat had a leak in that area,the steel hose barbs were loose in the aluminum pump housing. I used a 1/8" punch punch and re-crimped the case around the barb. Worked for me.You would need a gasket since removal is required to get completely around each barb.
 
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