The truck is allegedly fixed. The problem, as diagnosed by the GMC dealer, was a “collapsed air filter” – possibly the result of it getting wet when I drove through the deluge of Hurricane Henri. Would that explain the overheating and the poor fuel mileage? Seems unlikely, but I am no diesel mechanic so I have to admit that it is possible. It the diagnosis is correct it will be the second cheap fix in two weeks – both filter issues that prevented the truck from starting.
BTW, I have learned how to bleed the fuel filter. A good thing to know. Might save me a tow someday.
The impact of the 1-day delay is minimal – I will skip the next planned stop and get to Modadore OH on schedule tomorrow. A refueling stop will be required and it will be another long day for the freezer (I think I will try to replace the RV battery in Ohio and see if that fixes the problem). But if I make it, life will be good.
Wish me luck.