would be nice to have a #22 head,but dont loose any sleep over having a #14! There are many of them out there running every day with lots of miles on them. From your list of cars i would venture you are the sort of owner that pays attention to gauges and symptoms and less likely to severely overheat your new wagon that the average driver.
if it eventually does fail,by then you will love that TD so much that you will almost feel good about putting an updated head on. I think i have had mine about 3years now with the #14 ,hope it lasts forever but if it does not i WILL repair it,Love this car. Don

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Red Green "This is only temporary,Unless it works!"

97 E300D 157000 miles
87 300TD ?141k? miles