Hello fellow Frontier owner's. My 2012 Nissan had no heat. No leaks detected by Dealer or myself. Dealer topped off coolant reservoir and said keep eye on coolant level. Four day's later, no heat. Back to Dealer. Coolant low again. No leaks found, again. COOLANT'S GOING SOMEWHERE!!! Saw problem's with later model Frontiers on this web site. Asked if leaking into transmission or bad head gasket. Dealer finally ckecked eng. oil. Found my missing coolant! Dealer contacted Nissan who said they have had problems with POROUS engine blocks. WHAT!!!! My year old Nissan with 7000 miles needs a new ENGINE! Will take 3 days to repair when new engine block comes in. But it's OK to drive till then.....hmmmm. WTF Nissan! Where's the quality. VERY disappointed. Considering going back to American made...

Update from Jan 26, 2013: Dealer had my 2012 Frontier for 1 week. New engine installed. Seems to be running OK. Must say, I was treated very well by my Dealer, after all it wasn't their fault. Service Manager did tell me that Nissan told him 25-30 Frontier's had been sold with this problem before being caught by Nissan. So, 2012 Frontier owner's be aware. I can only hope my bad gas milage was caused by bad engine. Fingers crossed! I'm still wondering, if Nissan knew these bad engine's were out there, didn't they know what vehicle's they were in, and who they had been sold to? Maybe there was money involved....Oh well...