I've had my 2008.5 Titan since I bought it new, 155k miles, never had any issues aside from nissan not installing cabin air filters and it caused the blower motor to corrode from crap getting in there, which spawned a VBC issue leading me to find the blower fan problem.
Never had a radiator issue because I bypassed the internal tube warmer located internally of the bottom of the radiator end tank. The tube warmer has transmission fluid flowing through it. In my opinion this is the reason the radiators fail on all titans in the bottom location, because trying to heat exchange 200deg trans fluid in a tube submerged in 200-205deg engine coolant is not going to cut it very long for a plastic end tank. Plus the tube is under sized and can clog etc etc...
So save yourself some head ache, spend the 70 bucks and check out my SR4588 external cooler bypass setup.
I did replace my radiator, not because of any issues, but just couldn't pass up the deal on a stillen 3 row.
Also, inspect the manifolds, they will inevitably crack and leak. The cats can clog and fail and have been known to be sucked back up into the engine due to reversion.
The camshafts are designed to aid in emission purposes as whats called iirc ''passive EGR".
Anyway, also look into the rear axles tubes near the brake dust covers, you will see fluid if there is a leak. This is a failed axle seal due to water/contaminate ingestion or blockage through the axle vent that causes pressure build up inside the axle/tubes.
Invest into the Axle Vent Mod by Cajun B-pipes, its a cheap mod, but great insurance.
Also, since no one else has mentioned the updates to the 2008 and newer models is that they have upgraded/revised rear leaf spring shackles.
And most importantly they have larger front brake system, calipers rotors etc. That in itself is the reason to get an 08 and newer.
Check to see if there are any codes, they can be stored on the ECU and pull the car fax history.
Check to see if it smokes upon startup, which its not a common issue, but valve seals can overtime eat themselves, granted the VK56 doesn't burn oil like the VK45 engines (Vk45 was ring package issue).
Check the coolant reservoir and for strawberry milkshake, this reverts back to the transmission tube warmer failing and mixing engine coolant with trans fluid giving you that awesome yet soul and wallet crushing pink milkshake.
Alot of these issues would be inspected by a dealer and not be permissable to sell, (one would think).
As for upgrades to prolong and prevent issues, id recommend the following in this order.
-Detroit Trutrac which is a helical/mechanical LSD. The open diff in the titan is downright dangerous and weak. Side gears can break without any warning, the Trutrac is a way to bullet proof the rear end.
-If the exhaust manifolds are ticking(from a crack formed where primaries merge into the main section), then get with Cajun Bpipes and get JBA headers which are very cheap and effective all while being a bolt on replacement. If you're state emission laws require cats, then he has you covered for the whole package.
-Axle vent mod, is like $30 and takes 15mins to install, it will save your axle seals.
-Invest in the SR4588 Trucool external trans cooler, and bypass the radiator tube warmer. Its a low pressure drop design which the flues/passages are designed to allow enough flow at certain viscosities (temp dependant) so unless you live in year round freezing temps, you will be fine. If you have warranty, nissan has to state the external cooler caused the issue if there were any to arise (which is little to none).
-Upgrade the front and rear struts/shocks to Bilstein 4600 or 5100, the ride will be drastically improved, as the stock stuff sucks.
Other than that, the titan is a solid platform with plenty of power and reliability.
Most issues you find will be due to owner neglect and hearing only one side of the story. Granted not always the case, but more often times than not.
Sorry for the long winded post, but just wanted to share some insight on a few topics of the 2008 and newer titans.
