jkerton

First time poster.
1998 Avant Quattro.
Doing the EGR passage bore cleaning and I have the Intake manifold off. Had been getting the P0104 "insufficient flow" code. The manifold is off and I gotta say, the main EGR bore wasn't that clogged. A little carbon on the 90deg hole but still not completely blocked. I want to bring the entire manifold to get dip cleaned and my question is do I have to separate the two halves for cleaning? Will the dipping process damage the gasket?
Another question, I have a small coolant leak at the larger coolant tube that enters the block just beneath the hyd pump base, above the valley pan. Does this tube have an O ring on it that can be replaced. Does the other tube on the opposite side have one as well?
Thanks

CRAZY_RUSSIAN

1st. do not have it acid dipped! the butterfly valves in the upper part of intake have o-rings that can not be replaced!
if you want to clean your intake, get it vac cleaned, its a big cleaner with water and detergent cleaner that is safe on rubber and plastic components. Yes you will need to split the intake to get it cleaned:-)
2. those 2 tubes have o-rings, get them from a dealer! (trust me on this one) i would also do the gaskets on the big coolant pipe ;-)

hubturn

There was a good post on a natural cleaner called Bulldozer by Arrow-Magnolia. Kind of pricey but seemed to do a good job. Wish I had bought it. Here's a photo of what Crazy is talking about. The top (in photo) o-ring will be exposed when the entire coolant tube is moved rearward. The other two on the back of the head will also have to be replaced at the same time. The tube in the lower photo should have the o-ring replaced since you are that far in to the job. While you are there, if there is any oil in the valley pan area, just do the valley pan gasket replacement. Search the forum for that. If you are splitting the intake manifold, buy all 12 fuel injector o-rings and replace them, too. If any coolant hoses look crappy, just replace them now. Getting the IM off is such a pain that you don't want to do it again. Check the ear type clamp on the power steering fluid line at the pump. Mine was just a bit loose and I think it contributed to oil in the valley pan area.