Glow plug snapped!

So I went to the auto shop here in NZ for glow plugs test. We found they needed replacing but ones tip was snapped, and they said it looks as if it’s been snapped for quite awhile now, he says it’s probably gone down to the piston. the van is driving and has been driving fine forever. So he replaced 3 and left the snapped one there because he does not want the new one to snap also. He said if it’s worth fixing it’ll be 2 days labour otherwise since it’s been driving fine keep driving if I want. He is going to talk to another mechanic friend tomorrow. Thoughts? Any similar stories? What do you all reckon I should do? What if it’s just gone straight out the exhaust(dreaming)!

Big question is; how well do you know your mechanic? Two days to remove and reattach the head sounds a bit excessive, so why can't he use a magnet to retrieve the stray plug-piece in the cylinder?

and yes, there's a very real chance (if the piece was small) that it's already been ejected out the exhaust valve. Try placing the business end of a large screwdriver as close to the area as possible while engine is running and put the handle to your ear - you might be able to hear the rattle if it's still in there

Not changed a cylinder head on a Hiace but don 2 on a Prado (more access) so I would say 2 days labour is not over the top you do have to allow for breaking things like exhaust studs etc. As for is it ok to run as is to be honest I would take the risk if it sounds ok it probably is.

?? Borescope should give the answer in 2 minutes. If the tip was still in one piece in the combustion chamber you’d surely have a hole in the piston or cracked/bent/broken valve. More likely it turned to ceramic dust and disappeared.