Head gasket losing coolant?

1997 LINCOLN MARK VIII
180,000 MILES • 4.6L • V8 • 2WD • AUTOMATIC
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WOLFSHEPHERD
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Losing coolant, no visible leaks anywhere.

Chemical test showed positive for combustion gas in coolant (fluid turned yellow)

However:

Not overheating
Not blowing white exhaust
No rough idle -- still purrs like a cat
No evidence of coolant on plugs, all burning perfectly
No milky oil

I'm stumped. Where's it going? Any other way for combustion gas to get in coolant?

I'm considering getting a cheap used engine and having it remanufactured then swapping. But time and expense, and even more important, finding a reputable shop to do the reman, which, from what I've gathered from extensive online searching, would be a flip of the coin. This is my daily driver for seven years, and have taken exceptional care of it. I'm a complete OCD fanatic when it comes to this car -- actually, every car I've ever owned.

Thanks for your feedback.
Oct 13, 2024 at 12:55 PM
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STRAILER
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Yep, so, the head or block is cracked. I would get a rebuilt engine from ATK they make good one they are a little more money but worth it. at 180,000 don't mess with it.
Oct 13, 2024 at 5:23 PM
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WOLFSHEPHERD
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ATK doesn't deal directly with retail customers. Even so, the rep said they wouldn't or don't reman my engine. Anyone else?
Oct 14, 2024 at 7:03 AM
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STRAILER
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Ebay, low mile used would be my next bet. Did you try Ford?
Oct 14, 2024 at 10:20 AM
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WOLFSHEPHERD
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Local Lincoln dealer, yes. But noncommittal. Would have to research but wasn't hopeful. Other remans didn't want to fool with it either. Hmm. What is it about this engine that shies them away?
Oct 14, 2024 at 10:52 AM
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WOLFSHEPHERD
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BTW, looking for a link to donate and can't find.
Oct 14, 2024 at 10:54 AM
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STRAILER
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Yep, it is difficult to find a good rebuilder period, can you ask a shop to order from ATK it for you? This is why we rebuild our own.

https://www.youtube.com/watch?v=QuNLrE3rrb8&list=PLe3kz1i_LrtW1Jw7wWI-3jSsaml8EjQVb&pp=iAQB

A donation would be great!

https://gofund.me/c7d318ad

Let me know.
Oct 15, 2024 at 8:46 AM
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WOLFSHEPHERD
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Great video! Interesting change of event. I'm a member of a few Mark VIII fb groups. There is one member considered by all to be the absolute Mark VIII guru, having owned and rebuilt many, the "go to" guy with any question and/or part. His suggestion: burp the cooling system before anything else. Air in the cooling can manifest in any number of different ways. He relayed of Marks he bought for nearly nothing from owners believing their head gaskets were gone or cracks, he bled the cooling systems, and voila! No problems. So that's what I did, per precise instructions and very diligently late Sunday afternoon--lots of bubble before smoothing out. Sat overnight, drove it with the hammer down 60-78 freeway miles yesterday, another 20 or so local errand miles. Sat overnight. Checked this morning didn't lose a drop. Go figure.

Though there was no real resolution here, your service was worth $100 to me at gofundme. Thanks.
Oct 15, 2024 at 1:19 PM
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STRAILER
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Wow thank you! :) Can I ask how you burped the system?
Oct 16, 2024 at 9:58 AM
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WOLFSHEPHERD
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Raised the front a few inches. Filled de-gas (expansion) tank to cold maximum and recapped. Removed plug from crossover tube. Taped funnel into crossover opening and filled to couple of inches into funnel. Started car, heat on high, and let it heat up. Lots of air bubbles came up. Kept funnel filled to couple of inches until coolant began to expand. Turned off car added more to funnel and left it in and kept coolant in as it cooled and condensed. Left it at way to cool overnight with enough coolant so as not to drain the funnel all the way. Next morning coolant still in funnel. Removed it, put crossover plug back in. Checked level and added a few ounces to expansion tank. Drove 100 +/- miles freeway and local. End of day after it cooled repeated the process, no air bubbles. drove same 100 +/- miles. Checked next morning. Expansion tank remained fully topped, same in crossover tube. Ran normal temperature whole time..
Oct 16, 2024 at 10:51 AM
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STRAILER
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Way cool, nice work on that one, I have not heard for burping the cooling system that way, Thanks for the insight.
Oct 17, 2024 at 8:26 AM
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WOLFSHEPHERD
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Actually, that's the way to do it. No deviation. You got to raise the front little, or be on a slight incline, as the heater core is a little higher than the crossover tube, which is where you fill the coolant. Otherwise, air can still be trapped in the core. No cap on the radiator, but a hose from the radiator goes right to the crossover tube. Plus one of the first things i did was replace my cheap oem plastic side tank radiator with a KSS solid aluminum 3-core unit. One of the best there is.
Oct 17, 2024 at 8:33 AM