My wife and I recently discovered passenger front floorboard soaked. What else could it be other than heater core gone bad?

If not the core itself, any number of hoses that mount to it could be the cause.

I seem to remember there was a problem with a drain hose that caused your problem with some owners. I checked the Tech Section and couldn't find a reference. Perhaps another member can recall the issue and the fix.

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2005 Titan KC SE, Helwig, True-Track, ARE MX Canopy

I believe your right, a drain hose wasn't long enough from the factory and would drain into the passenger foot well instead of out the bottom of the truck. I remember talk of this problem on MT, think there was ( not absolutely positive) a TSB on this problem too. Some members just extended that hose and it seemed to cure the problem.

jeffro49, here is a link to a TitanTalk thread on the topic of the passenger side leak. Look it over, it might answer your problem:

Another Water Problem - Nissan Titan Forum

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2005 Titan KC SE, Helwig, True-Track, ARE MX Canopy

Here is further info:

Nissanhelp.com | All About Nissan

NTB05-112a covers an '05 King Cab, but the procedure should be same over all models; but check to be sure.

Attached Files

NTB05-112a.pdf (613.1 KB, 1 views)

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2005 Titan KC SE, Helwig, True-Track, ARE MX Canopy

I've also had Mud Dobbers build nest in my hose and stop it up. I ended up using some RTV and a tie strap to attache a piece of screen over the opening to keep them out.

Thank you Red Alert for all info. on water and condensate. Going to dealership on Monday. I got nearly a gallon of water from my front floorboard.