For the benefit to others thinking that replacing the head bolts to ARP will cure an already leaking gasket or cracked cylinder head and why why did you not remove the head for an inspection. The only reason you lost the coolant is a fault in that area. Sorry for your loss but if I just laid out all that cash I would wont some answers. (freedom of speech)

Here's the thing about that: lifting the head would not have been illuminating about any potential valve issue, because all of the valve drops I have seen have happened above the seat on the stem of the valve. You can see this from above, without removing the head. On Naturist's engine, the valves were all where they should have been.

I certainly want to know what transpired as well, but the reason for not lifting the head was simply that his coolant leak was very minor, only a top-off every few weeks which is much less than some that have been cured with a more significant leak. He also had no indications of coolant leaking back into the cylinders on the glow plugs (it would be charring) so I do not believe that the gasket itself was involved in this.

I have offered and will restate here that I am willing to take the entire top back to the studs free of charge, to help ascertain what exactly happened. The symptoms when taken separately are bad, but together they are just confusing. Jammed engine rotation sounds like a dropped valve... But this is the first one I have heard about that also dropped all the coolant in an instant as well. That is the confusing part. More investigation is needed, and I am certainly willing to help whoever has this CRD if they would like the assistance.


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Sorry for the late reply, just returned from a 1000 mile trip in my CRD.
I don't fully understand your term for testing a dropped valve by checking the valve stems? Valve drop in most cases happens at high RPM? Lack of lube between valve guide and stem can cause valve hang up causing piston contact. Personally I would look more closer to the possibility of a slipped cam sprocket.

Here's the problem with that theory:

A slipped cam sprocket would be the same as a failed timing job: Trashed rockers because that is the designed failure method for high-speed piston contact. Since I put the engine back together, I can unequivocally state that the cams were properly torqued and centered on the pins before they were secured, and that I use a counter-hold bar individually on each sprocket while assembling or disassembling to ensure that they do not move at all during the process.

Whether or not a valve was damaged by tiny impacts "just touching" the valve because of a mostly-correct timing job beforehand... I cannot say. I do not recall whether the tensioner was correct when disassembling it, which leads me to think that I didn't see anything that caused concern. But taking the top intake off to see the tops of the studs and the stems of the valves has a purpose: If a valve has dropped, then the stem will be "up" compared to the rest of them, and that will indicate whether the top needs to continue being disassembled and strongly suggest the level of carnage that may be discovered once the head is pulled. I have seen engines that felt like a hard stop that was only caused by a failed rocker, so that alone doesn't inform the decision. We need to see the top.

Besides, the work would need to be done anyway, but if he wants to sell at that point knowing that the head is probably trashed (on finding a dropped valve) then there will be more information to help that decision. Right now, it is all guessing.