ISX realiabilty

If it runs good, doesn't use oil or coolant and the oil samples are good,I wouldn't touch it.

 

Can't be a 871......

 

if it still runs good and has good oil pressure I wouldn't worry, a lot of people start worrying when the truck starts getting up in miles, but miles don't mean anything as long as its been serviced regularly, just my opinion

 

Overhaul and bearings is usually the least of any ISX owner's worries. In most cases, cam and rocker problems occur before any other. Just run the overhead regularly and keep an eye on it. Rebel and Board had it right. Miles mean nothing really. If the engine is running good, not using much oil, and the oil samples look good, then there is very little to worry about. Can't speak to the ISX, but I have taken N-14's well over a million and the next owner put them right to work with no repairs. One I took to 1.4 million. All it ever got was one injector and an accessory drive seal. It still got an average of 7 mpg when it got sold, and only used about a gallon of oil every 8-9000 miles. Not a leak anywhere. Still original bearings, main seals, etc. And it did that on 30,000 mile oil changes and a Kendall 15w40 conventional oil with no bypass filter. Might have been a fluke, but that was a killer engine.

 

Those two words never should be used together. I will never own a truck with a isx. I'd rather drive one with a mercedies

 

Blow by test

 

Rollingsmoke,the question you have to ask yourself is:"how long will i keep this truck?"
Planning your future is a very important part off being a bussiness owner.
If you have the intention off keeping her around for a longtime,it might be smarter/cheaper to do a overhaul when it suits you.(getting a little extra MPG out off a overhaul might pay for part off the overhaul)
Make a plan.

 

do it before 900K

 

i have 1070000 on my 06 isx 435 st..so far no problems. use about half gallon of oil between services running shell rotella.