NF Mod/Nissan Master Tech
Joined: Jan 2006
Location: Prospect, VA
I'm a former Nissan Master Tech and an owner of two R51 Pathfinders, an 06 LE and an 08 SE. I'm also a moderator at TheNissanPath.com, so I've read a great deal about other people's experiences. In my 06, I replaced the radiator with a $92 Ebay unit and it has worked great for 4 years. In the 08, I originally bypassed it last year and without issues, but have since purchased a Koyo brand radiator and will be installing it in the very near future.
Any radiator that has an internal cooler has the "potential" to fail, but, for the most part, it is usually a very reliable design that has been used in automatic transmission cars for decades (my '65 Mustang has an integral trans cooler in the radiator and some GM vehicles have transmission and engine oil coolers inside the radiator tanks). The factory radiators in the 05-10 Nissan Pathfinders/Xterras/Frontiers were made by Calsonic, which Nissan bought out around 2005. Calsonic has been an OEM supplier of radiators, exhausts and many other parts to Nissan for years. The issue with the Calsonic radiators during those years is a seal in the cooler that leaks inside the lower radiator tank, causing the cross-contamination. Nissan has since updated the radiator and has available the full-priced, genuine Nissan part, as well as a Value Line radiator that has a lower cost. Both are on the expensive side, though. Aftermarket radiators are much more wallet-friendly and I've yet to hear of any cooler issues from them. My friend did install a Denso radiator from Rockauto for $99 in his Xterra that did develop a small crack that leaked on the bottom tank. This surprised me as Denso is owned by Toyota and I have had good success with all of their aftermarket parts. Another at the other forum purchased the new, all-aluminum radiator from Stillen Motorsports for $350 but had some issues with the neck leaking, I believe.
For the environment that you'll be driving it, I wouldn't hesitate to replace the radiator with a new, aftermarket unit. If you want a name brand, Spectra Premium is a very popular choice. For me, it was cheap insurance compared to the idea of ruining a $5000 transmission! If you have blue coolant, I would highly recommend you get the genuine Nissan Blue coolant. It's pricey, but comes pre-mixed and good for 150,000 miles.