Holes in my Head

[BobinSF]

New Year’s greetings to all afourians.
After patching a large hole in my head last spring, my raw-(salt) water cooled A4 is running fine, but with one problem: the head now has had numerous ‘pinholes’ develop. When I start the engine, after a few minutes, a very small trickle of cooling water will come out of these holes and make its way to the head depressions at the spark plugs, where it sizzles and boils. When this happens, I Dremel wire-brush clean and bright a nickel-sized area around the hole and apply three coats of JB Weld. This will usually stop that leak, but then another appears, and another, etc. My options seem to be:
1. I could just ignore this and run the engine with the sizzling and boiling, but that seems not a good thing to do, it being salt water.
2. Continue to observe new leaks and patch them as above, hoping eventually there will not be any new ones.
3. Replace the head, but seeing the accumulated rust on the stud and stud nuts (photo, before painting), this would seem very difficult or impossible.
4. Buy and install the MMI fresh-water cooled system (which of course I should have done years ago), and put one of the automotive stop leak solutions with the antifreeze into the cooling loop, after testing that the stop leak solution doesn’t degrade the impeller, and hoping that it stops the leaks.
Advice and opinions on this would be most welcome.

[tenders]

There's no two ways around this: you need a new head. The one you have is Swiss cheese and past the point of reliability.

The rust on those studs probably isn't as problematic as it looks - and even if it is, the studs are replaceable. I'm living proof that with a bit of luck, decent access to the top of the engine, and a new head gasket in hand, a rank amateur can get the head off and back on in one long morning. You'll also want to check on how much meat there is left in the block for the studs to bite into, but advising you on that is beyond my experience level. It's covered nicely in the Moyer Manual.

If I were you I'd expect the block to be OK, but to brace for the while-I'm-at-it-here-with-the-head-off additional jobs like replacing the manifold, which is probably not in much better shape than the head.

[ndutton]

Originally Posted by tenders

There's no two ways around this: you need a new head. The one you have is Swiss cheese and past the point of reliability.

If I were you I'd expect the block to be OK, but to brace for the while-I'm-at-it-here-with-the-head-off additional jobs like replacing the manifold, which is probably not in much better shape than the head.

+1
For a rock solid reliable engine (isn't that what we all strive for?) I recommend replacing the head, manifold AND adding Fresh Water Cooling. I know, the cost is considerable but it's a "one time - last time" expense and is minor compared to the sea water incursion havoc you're headed toward.

Edit: at a minimum the manifold should be pressure tested. There is plenty of info on the forum.

[joe_db]

FWC is a great idea for the NEXT head, but the one you have is done.

[edwardc]

And don't even consider automotive radiator "stop leak"! Aside from it possibly aggravating partially blocked cooling passages, in a raw water system, it will get flushed out almost immediately, before it can do much of anything. Its not even a good "band aid".

Fresh Water Cooling (FWC) is a great thing to do for your engine, but in order to get the best benefit from it you need to have cleaned and flushed out the block, head (unless new), and manifold first.

[alcodiesel]

Bobin, what year engine is that? I'm just wondering how much longer till mine starts springing leaks.