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Will Head Gasket Sealer Work On Internally Leaking Engine?

2004 Lincoln LS V6 3.0

So I reinstalled the left side cylinder head (facing the front of the motor) with a new head gasket, but when I started up the car I got really rough idling and codes for cylinder 1 misfire and misfire on startup.
I look into the spark plug holes on the left side and cylinder 1 piston looked wet but the rest of the pistons were dry. I swapped the spark plugs from each side and started the car again, this time cylinder 2 misfires as well. Also there is coolant getting into the oil giving it a nasty sweet smell and a chocolate milk color.

So I have cylinders 1 and 2 misfiring, but cylinder 1 is wet while cylinder 2 piston is dry still. Is this the result of leakage and/or loss of compression? Should I look at replacing this head gasket again or could head gasket sealer work in this situation?


Did you check the flatness of the head prior to installing it?

And did you replace the head bolts?


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Do not attempt to use sealant. If coolant is entering the oil, then so will the sealant, and result in damaged bearings, or even a seized engine. To be honest, if coolant is getting into the oil, it is time to pull the motor for a professional rebuild, or buy another one from a junkyard.

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do you think intake manifold gaskets are good? did you replace them? i dont know if you had heads checked for flatness or cracks. an immediate coolant leak into cylinder after a new head gasket is usually something obvious was missed

Once coolant gets in the oil there is little hope for the engine. It will be interesting to know what fails first on the engine. My money is on a rod bearing.

I did not check for flatness or use new bolts. That’s what I’m guessing is the problem after ruling out other possible causes. . .That was a pretty dumb move on my part, but I’m new to heavy engine work. The point of me reinstalling the head was because I had to a replace a broken valve because I didn’t time my engine correctly and it resulted in a bent valve on the highway. Luckily I timed my engine right this time but now there’s this head gasket thing. . .

Is it really a doomsday scenario on this one? I’m open to rebuilding the engine myself. I flushed out the oil with motor flush and drained it so it can’t be that bad?

Manifold gaskets are fine, I did check those. I figure it’s probably that the head isn’t completely flat.

Thank you. I’ll make sure to flush out the coolant and oil and have a machinist make sure the head’s flat.

How long did the engine run with the oil looking like a milk shake? Water and antifreeze are poor lubricants and once mixed with the oil they gum up the works. If you thoroughly flushed the engine out soon enough there is hope but I have seen several engines that soon failed once the oil turned into a milk shake and never have I seen one survive long.

The head bolts on your engine are torque-to-yield head bolts.

This means once the bolts are torqued to spec, they stretch and cannot be reused.

If they are reused and torqued to spec, the bolts continue to stretch further and don’t provide the clamping force required to seal the head gasket.



Probably about 10 minutes maximum while in park. Long enough to turn the oil into a chocolate milk brown, I guess, but I checked the consistency of the oil and it was still quite oily and lubricant.

I see, thank you for the info. I will definitely get new head bolts as well as have the head machined by a professional.