Hey all, I just bought a 2005 Pathfinder LE and upon inspecting the rad, fluid is bright green, inspecting trans fluid via dipstick, nice and clear red.

So, considering the mileage, I was kinda impressed to see the fluids without any sign of trouble.

Tranny shifts perfectly fine too.

Question - how can I tell if the radiator has been changed to the updated model which poses no threat?

Second, is it worth to do the bypass if I need to tow my ATV's (pair) both throughout the winter and summer? Should I be afraid of overheating the tranny?

Genuine Nissan radiators, including the original, will have a Calsonic sticker on the top tank (if it didn't fall off). If it has a part number of 21460-EA215 or 21460-EA265, you definitely have the radiator that can be prone to internal trans cooler failure. Replacement or bypassing is highly recommended. Now, here's where it gets tricky: at some point, Nissan changed the part number to 21460-9CA2E, which being a 2005 would indicate the original was replaced at some time. However, it seems they updated the radiator somewhere in the -9CA2E production run and there's no way of telling which of those were of the failure prone design or of the updated design. The problem radiators were around through the 2010 model run, although most of the problems occur on the 05-07 models. Aftermarket radiators won't have the Calsonic sticker on the top tank. If you have the latter Calsonic number, then you may want to check Carfax or try to find service records that might say if the radiator was replaced and when. If there's no way of telling, it would be best to at least do the bypass and play it safe. Towing a couple of ATVs won't be a problem with the bypass. If you were towing a heavy boat or trailer, or if you live in an area where you'll see extremely cold temperatures, I would recommend you replace the radiator.

I also do tow my 16" boat, nothing too big.

I live in Vancouver, temperatures don't get extreme but it does get down to single digits sometimes.

Just checked, and it says EA265.

I guess I'll get the bypass done asap.

Thx for the help!

My rad on our 08 went bad this summer, it did not have the transfluid cross contamination. Our went bad with the plastic tank to metal crimping along the top. I noticed small amounts of dried coolant along the top seam with signs of bulging. I replaced it with the newest updated radiator.

Well, single digits are extreme enough for me living in Virginia! Aftermarket radiators are pretty inexpensive; I bought mine for $92 two years ago. Stillen is supposed to have an all-aluminum radiator in the next month or two for $350. Had I not already replaced mine, I would probably go that route. Bypass for now, but if I were living in Canada, I would replace the radiator.

And these aftermarket ones at ~$90 for sure do not have the same issue as the factory one? It would seem to me that with the same design / same plastic, that it would be prone to the same problem?

Well, any radiator, be it OEM or aftermarket, with a crimped-on plastic tank can be prone to developing a seam leak at some point. For the most part they are pretty reliable for 100,000 miles plus, but you'll always get a couple that will fail, just as with any part. The Titans and Armadas had a lot of issues with lower tanks cracking or leaking at the seams of their radiators, which are also made by Calsonic. I'm not sure what happened with Calsonic? They were a supplier of radiators, heating system components and exhaust systems to Nissan for years. Nissan bought them out completely around 2004-05. Ironically, that was when the radiator problems started.
As far as the internal cooler issue, the cross-contamination issue has nothing to do with the plastic tanks. The cooler is metal in the Nissan radiators, but there is a seal on the cooler that can develop a leak that is the source of the problem. There is a YouTube vid where a trans shop removed the cooler from the radiator and pressurized it with air and placed it in a tank of water. You can clearly see where the leak is.
I've had my radiator for two years. It was made in China, but most radiators these days are. It fit perfectly and appeared to be well made. I opted for the 2-1/8" dual core over the 2-1/4" single core, which is what the Nissan rad is, for what it's worth. Not sure if one has a benefit over the other, but so far it's been fine. Last time I checked, the price had dropped to $72 w/ free shipping. For me it was just cheap insurance compared to worrying about the original radiator fail and take out the transmission. I would have gone for the all-aluminum radiator if it was available at the time, but I've been happy with what I got. The $450 Nissan wants for a radiator is ridiculous!

Thanks for the info! Could you send me a link to the one you are using? If I'm going to get one, I need to make sure at least is one with a track record.

So the seal/cross contamination problem is then 100% eliminated on these aftermarket ones, correct?

Any radiator that has an integral cooler has the possibility of developing a leak and cross-contamination, a design that's been around for decades and has been pretty reliable over the years. Nissan just happened to have a problem with the seals failing in their coolers during the period of 2005-2010 on the Pathfinders, Xterras and Frontiers. Their other vehicles are not affected by this problem and in the 16 years I worked for Nissan up to 2003, I never saw the problem occur on any Nissan. So, that said, there is no way to 100% guarantee that any radiator with an integral cooler will not fail, but chances are slim if you get an aftermarket or updated Nissan radiator. The radiator I purchased came from a seller called Parts Express on Ebay.

I'm looking to replace mine as well 08 just hit 48 thousand miles I want to do this as a precautionary measure any suggestions on which after market brand that isn't 350$ I was thinking the spectra premium CU2807 but am not positive as to which one would be best @ a reasonable price

Spectra Premium is a popular choice. I think most aftermarket choices are made in China, including the Spectra Premium (although based out of Canada), which isn't necessarily a bad thing. China's automotive parts have come a long way over the years; I'd be leery of those made in Thailand or Korea, as their quality control does not seem to be as good. Stillen should be close to releasing their all-aluminum radiator for $350. If I had not already replaced mine, that would be the way I'd go.

I hadn't realized there was such a big issue with the radiator until I found this forum. I had my radiator and transmission replaced on my '06 in 2012 by nissan. Luckily for me I was still in the last year of my extended warranty I purchased with the vehicle so I was covered. Paid only my 50 dollar deductible for the 7500 dollars worth of work.

Anyway, reading this got me searching for the part number of the new radiator. What I found was the part is 21460-9ca0e. I'm assuming they would have replaced it with an updated radiator. Is anyone familiar with this radiator?

Also, what did they update on the radiator to make it more reliable? Should I still be worried about it?

NOVA_Pathy06 wrote:Anyway, reading this got me searching for the part number of the new radiator. What I found was the part is 21460-9ca0e. I'm assuming they would have replaced it with an updated radiator. Is anyone familiar with this radiator?

Also, what did they update on the radiator to make it more reliable? Should I still be worried about it?

That's the updated radiator. My understanding is it was just a flaw in the production process. An internal part would corrode and eventually perforate and allow transmission and coolant fluid to mix. The new ones are supposed to have been fixed. Considering it seemed to take 4-5 years for the old ones to corrode....I would guess that's about how long it would take for the new one!