Ok so I've had a tick with my titan for some time. It still runs great, no oil pressure problems, just a loud tick that is very annoying.
At first I thought it was exhaust manifolds...well it was not. I have a full warentee on my truck so I brought it to the nissan dealer. My truck just rolled 80k miles...tick has been there since 65k. Hasn't gotten worse or anything.
Well the dealer told me that there is a factory defect with one of the gaskets in the timing cover. Apparently this gasket is a "paper" gasket as they said and it blows out prematurely and when it does it makes it so the slack side tensioner (bottom tensioner on pass. Side) has a lack of lubrication and it wears the spring out that is oil pressurized. This is what has created the tick in my engine. The tensioner is worn and can't take all the slack out of chain due to the gasket leak and inadequate oil pressure to the tensioner.
What the dealer is going to do for me is, replace all gaskets with a new cork type gasket, new timing chain, all new tensioners and guides, new timing covers, new oil pump and a new water pump....said it would be around $2100 to do, but since I have a warentee it's going to get done for only $100 which is my deductable.
Dealer told me this is a frequent problem with titans 04-06...so for anyone with an engine tick, get the timing components checked because it may not be your manifolds.
Hope this helps some people with the annoying engine tick