1kz Te Cylinder Head Crack Repair

Its pretty well known that the Toyota 1KZ-TE 3L turbo diesels are pretty average when it comes to reliabilty in the head department but does any one know why!
I have done quite a few head swaps or repairs on them over the years, but recently I have been completely amazed by how crap they are again as about two months ago a freind was looking at purchasing a mid 90s Super Custom with 160 odd kms on the clock which had major head work done 3000+ks ago with just under $4000 worth of receipts from a reputable workshop for brand new STA(Chinise) head and all the related common things, I went with him to look at it, we did coolant leak/presure test, compression test and few other checks and motor acted like new, everything seemed legit like reciepts, records, kms etc so he purchased it and he even got me to do a EGR removal after he got it as thats a rumoured problem with these motors.
Anyway now fast forward to last week which is about 4-5000kms later he went to do an oil change an at the same time he checked the coolant an it was down by 700 to 1000ml so he toped it up then decided to check it a few days later, it was down again, was presurising the coolant system on free rev, so we took the head off, got it checked, it was soft and had a mild bow/warp in it! yes ive looked at everything related to the block that you can do in place like checked its flat with a good strait edge, looked for any damage anywhere etc and it seems mint.
This is far from the first time ive seen and heard of storys like this! so yeah. does anyone have any ideas!

1kz Te Cylinder Head Crack Repair Cost

1kz te cylinder head crack repair parts

1kz Te Cylinder Head Crack Repair Parts

The cylinder head and glow plug hole can seize up with carbon deposits. And if the glow plug is forcefully twisted when you remove it, the torsion can crack the ceramic. So keep removal of the glow plugs to a minimum. • The heater element is ceramic. So if you drop or knock a glow plug even once, replace the glow plug.