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]

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.

[romantic comedy]

While I agree that you need a new head, I will go in another direction.

If you try to remove the head it may turn into a real expensive mess. The studs may break off in the block, and you wont know what condition the cylinders will be in. Have you done a compression test?

How important is engine reliability to you? What is your budget? If you need the engine and it must be reliable then you have to remove the head and go from there.

If you can live with some engine problems, you can wait a while to do the job. How long is anyone's guess. But to replace the head, manifold and add FWC you are talking 1K or more...I think.

But sooner or later you will need to fix or replace the engine.

[edwardc]

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

Bill,

I think it's more about how many hours its had running in saltwater vs how old it is.
The flowing hot saltwater steadily erodes away at the head and manifold cooling passages until some sections get almost paper thin.
Recurring pinhole leaks and cracks are a sure sign that the end is near...

[JOHN COOKSON]

I always assumed the head was made from the same nickel rich alloy that the block was made from.
Maybe not?

TRUE GRIT

[Al Schober]

I find this curious. All the studs shown are weeping?
What's the history on this engine? This is what I would expect to see if the head studs were installed without sealant.
Any chance the head is fine? Just my $.02

[joe_db]

I have BTDT - I tried to extend the life of a beat engine. If finances and time permit, I would really want to get this one apart and see what you have.

[BobinSF]

Holes in my Head, continuing

Following up on my 01-01-2018 post about raw-water cooling 'pinhole' leaks in my head, and after dealing with several other engine issues, I went ahead and did the last option in the post, that is: Buy and install the MMI fresh-water cooled system, put automotive stop leak with the antifreeze into the inner cooling loop, and hope that it stops the leaks. I did all this, and it did stop the leaks.