I have had the local Nissan dealer replace the valve cover at 4000 mi, 15000mi, both under warranty now at 25000 mi it is off warranty and leaking again. Quoted $10,000 for a used engine, sorry it is out of warranty. Anyone else have valve cover problems pushed to off warranty?

What year is the truck? Why out of warranty due to time vs. mileage I would guess. I know this is a little underhanded but you could buy an aftermarket warranty and wait 90 days and make a claim. With that low mileage I would doubt they would do a pre-inspection.

The other thing you could do is appeal to Nissan corp, they are jerks these days compared to the way they were years ago but worthwhile to at least make that phone call.

The Frontier is a 2013.
I did call Nissan customer support line, politely asked to escalate the call. Nissan called back, refused to entertain the possibility that this problem existed from date of manufacture and their technicians either overlooked the root problem or deliberately pushed the problem out of warranty. The non-technical Customer Service Rep at Nissan stood firm on their excuse that it was now out of warranty. They denied my request to escalate this to the National Service Department Manager. They also did not send me any documentation of the complaint, only a verbal case number.

That sucks! Nissan customer service is nothing like it used to be. Think about the aftermarket warranty, with a 2013 you can get one without an inspection, wait 3 months and report the problem. I doubt they can get Nissan records and you should take to an aftermarket mechanic.