geordi wrote:
these are the normal numbers: Around 130k miles, the head bolts are known to weaken and allow the head gasket to leak. ARP studs are a cure IF installed BEFORE the first "low coolant" alarm happens. Anywhere from 150k to over 200k miles, the exhaust valves are known to fail randomly - severe engine damage is the result. Replacement before failure is the only known cure, I suggest any time the head needs to come off, replace the valves... OR between 150k and 175k miles for safety.
Let's beat this old horse some more.
Normal or abnormal, that is the question. While most would agree it could happen at those mileage numbers you invoked, it can also just as well not take place.
Certainly don't want to scare the bejesus out of every KJ CRD owner.
We know there are some out there with over 200k and even a few over 300k that have never reported a head gasket leak or valve failure. (they are rare)
Guess we are all on borrowed time with these engines to a great extent, just knowing when and how to quantify failure is the real challenge.
So many extenuating circumstances and variables that can play into if or when a failure might occur.
Is replacing head bolts a good preemptive move if you pull the valve cover for anything else, certainly.
Is replacing the exhaust valves a good predictive move to guard against valve stem failure, certainly. But to pull the head just for this alone; is that a wise decision?
Metallurgy tests on some of the failed valves were not conclusive. Was it just a bad batch of valves that only affect a very few poor souls or does it affect all VM 2.8 CRD engines?
And if that is the case, how have some surpassed those mileage numbers by double digits and not had a failure?
Gosh we would all love to know the answers to that one including myself.
In my case, I am at 170k and never had any issues with head gasket leaking or overheating.
Do I need to plan on pulling the head, replacing the exhaust valves, and installing head studs in place of head bolts?
Or, is it time to sale and let someone else worry with all the decisions?
Or, do I just keep driving it and hope and pray it will make it to the 300k club without a failure...........
Can someone tell me, I wish, but I think not.
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