ISX 475: Leaking Head Gasket - To Inframe or Not Inframe

2004 KW T2000
Cummins ISX 475 EGR motor
950k miles
Current Average Fuel Economy (loaded / bobtail): 6.8 mpg / 11.4 mpg Yes, it's still turning awesome numbers for fuel economy! $$$

I just had the truck dyno'd at cummins in Portland. It made 470 hp (98% slip corrected HP) and only blew a 5 on the blowby test (InH2O). Cummins told me before the run that when they start seeing 18-20 on the H2O blowby test that they recommend rebuild. So for my million mile ISX, it still performs like new and doesn't burn any oil. BUT: It's leaking about a gallon of oil every 20k miles from the head gasket, the front covers and a few other places. Not a gusher, but I am not real excited about the head gasket leak, despite the performance numbers it just made.

Kenworth wants $6500 just to do a gasket overhaul. Most of that is labor ($85/hr). I don't have a huge problem with that but then I must ask myself if it's time to do an in-frame. I can't see why if the motor is still giving me 98% of it's rating and has very low blowby. But then again, almost a million miles... with the cost of an ISX inframe being about $14k now, what should I do?

Sure would suck to spend $6500 on the gasket overhaul just to experience catastrophic failure shortly thereafter.

Any advice or sharing your experience is appreciated.

 

That was my thought, too, but I'm afraid to run it with the leaking head gasket. After time that can cause damage to the head / block, yes?

 

The sad thing is that if they didn't have to pull the cams to remove the head, it'd cost half the estimate. But nooooo. Thanks to ISX engineering they have to remove the hood, radiator, basically the entire front structure of the engine. smh.

Thanks for the advice. I haven't been running oil analysis on this unit. I'll probably shop around and see who will give me the best deal on the gasket overhaul and get it done before I put a driver in it. Save everyone the pain in the arse of breaking down in BFE under a hot load. Paying for peace of mind I guess. I'll have TA do an oil analysis for me first though. If it looks like I should rebuild, I'll probably just go ahead and do it instead of only the gasket overhaul.