[Vwdiesel] Coolant Leak at Cylinder Head Flange, 1.9L NA engine

[Roger Brown]

David O'Shea wrote:
> I have a '83 Vanagon with a recently replaced 1.9L NA engine, 18k miles and 3-years old. I noticed a little dribble of coolant under the van in my garage so I checked around for a source. It was a very slight leak coming from the right-side bolt of the flange for the coolant hose on the front of the cylinder head, the flange just below the oil pressure sender. I thought that this would be no big deal but my local VW dealer claimed that the gasket came up "no longer available" on their computer. 
> 
> I removed the flange and saw that the mating surfaces were completely flat so I cut a new gasket out of thin gasket material, cleaned up the both surfaces "baby" smooth, and remounted the flange with appropriate gasket compound. I let it sit overnight and then refilled the coolant reservoir and fired up the engine. I now have a very steady leak from the right-side bolt, much greater than before my repair job. It really looks like the leak is localized at this bolt, not from a failed gasket around the actual coolant port.
> 
> Is it possible for coolant to travel up the through the threaded bolt hole? I wouldn't think that it would be open to the inside of the cylinder head but I didn't do any exploring beyond cleaning things up and drying them out. Cracked head? Before I seek professional assistance, I thought I'd poll the on-line experts for any opinions on possible causes and solutions.
> 
> Thanks

Try using some pipe dope (paste type pipe thread fitting sealer) on the bolt threads.
I do this on my water pump bolts and any places where there may be coolant present.

-- 
    Roger