Just curious as to what you guys think. My '05 Pathfinder has 129,000 miles on it without radiator failure. Do you guys think that it would still fail at this point or do you think I am good?

SimulatedZero wrote:Just curious as to what you guys think. My '05 Pathfinder has 129,000 miles on it without radiator failure. Do you guys think that it would still fail at this point or do you think I am good?

the farther you drive, the more chance for failure
OTOH, it may never fail...........

Do you feel lucky?

I feel some what lucky, but not that lucky... Which means I will be doing a By-Pass pretty soon. I guess I just wanted to hear it before I started buying parts and slapping them in.

SimulatedZero wrote:I feel some what lucky, but not that lucky... Which means I will be doing a By-Pass pretty soon. I guess I just wanted to hear it before I started buying parts and slapping them in.

you have been lucky, so far
the cost to repair the damage from a failed radiator is enormous!
and, you are beyond the Nissan extended warranty mileage limitation
there are no parts necessary to do the by-pass
you only need common tools and about 45-60 minutes
more info here:
warning, long thread ahead : http://www.thenissanpath.com/viewtopic.php?t=2139

I've read that thread and a few others on other sites and I'm not so comfortable just disconnecting the Rad-Trans Cooler without supplementing it somehow. I do a decent amount of trail riding and stop and go traffic. While it's winter here now and the temps aren't too bad, once 100+ degree summer gets here I will need extra cooling power. I'm looking at slapping in an extra cooler with a fan and putting a fan on the stick Aux cooler. Not sure if anybody else has run two coolers and two fans before, but I'm willing to give it a try.

I do not recommend simply disconnecting the trans cooler. However in your current situation, I would consider it. At least until you can install an external cooler to replace the bypassed cooler.

I install external coolers on customer cars at least 2 a week. I started off by selling them to the used car department for our trade ins to prevent failures. Then word of mouth spread and we have customers coming in for us to install them outside of the 80k mile free replacement.

Ok, I'm sure I could get away with just running the aux cooler for a short while. I am looking at dropping in something like this cooler up front near the aux cooler if I have space. Then the only thing I would have left to do is hook up a couple of pull fans on them. I haven't looked to see how much space I have to play with due to time constraints, but I'm hoping to sit down this weekend and plan everything out.

Does anybody have any suggestions for a good quality fan with a temp start switch?

Rather than spend money on an extra auxilary cooler and an electric fan for it, which still doesn't give you the benefit of warming the transmission fluid and maintaining it in the proper range as a radiator integral cooler would, why not just spend the money instead on a replacement radiator? You can get an aftermarket replacement radiator for about the same money as you can the auxilary cooler and fan and won't have to be bothered with the wiring or fabication.

So, a few things on this. This is where my lack of in depth mechanical knowledge is going to shine through.

1. You are suggesting replacing the radiator itself. Since the Rad-Trans Cooler is apart of the problem in this setup, I assume that replacing the radiator will also replace that particular cooler with a new one as well?

2. Which radiator would you recommend and what kind of price range are we talking here? I would really like to keep this project below a couple hundred dollars if possible. While the cost of bypassing this setup is obviously far cheaper than fixing it after it breaks, I would still like to avoid breaking the bank in the process.

3. I have heard a fair amount of people talk about the radiator cooler being used to warm up and regulate the ATF temp. I was doing a fair amount of reading on cooler by-passes when I came across a good thread over on an xterra forum. The guy there took a series of temperature readings from his transmission and discovered a few interesting things about the entire transmission cooling system. It really was an interesting read.

I quote one of his findings regarding the Rad-Trans Cooler: "There was no evidence of the rad-atf cooler heating the atf. On three cold starts Trad was always colder than Tout as the engine and trans warmed up. As the trans warmed up the difference became larger. The difference is few degrees when the Tout is mid 90s and 13-14F when Tout is about 120F. It takes about 20 minutes for the Tout to reach about 150F with normal highway driving when the air temp is about 75F."

Tout - temperature at the trans outlet on the steel feed line
Trad - temperature at outlet of the rad-atf cooler, measured at the air-atf cooler inlet



Regardless on whether or not the Rad-Trans Cooler warms the ATF or not, if replacing the radiator fixes the issue then I am more than open to it. That particular cooler is more efficient than the Oil to Air Cooler up front and is what keeps everything cool on trails and in town.

Why not buy an OEM radiator? The cost has come way down from $900 to $479. That is the updated part number.

1) Yes, the "integral trans cooler" is integral to the radiator assembly. It's built into the bottom tank of the radiator. So, replacing the radiator assy. will also, in affect, replace the cooler tube.

2) Nissan radiators have always been overpriced; $500 for a plastic tank radiator is ridiculous! If you are going to spend that much, you mind as well get an all-aluminum radiator from Griffin Radiators. Personally, I chose to go with a Chinese-made radiator with a lifetime warranty from Parts Express on Ebay. It went with the 2-1/8" dual core; also available is a 2-1/4" single core. The factory radiator was a single 2-/4" core, but I don't think there's any or much difference in cooling performance. The radiator seemed well constructed and fit perfectly and was $92. There are foam seals on the radiator which aren't expensive that I picked up from Nissan; these aren't required, but make for a cleaner looking install and the original foams get pretty torn up. Some have stated they don't trust the "made in China" part, but it's been over a year and no problems, yet. If that bothers you, Spectra Premium radiators are made in Canada and can be had for $150-$160 if you do some searching on the web.

3) The one thing I noticed about the Xterra's owners testing that you quoted is the ambient air temperature is 75 degrees F. At that ambient temperature, I would agree that the integral cooler doesn't give a whole lot of benefit to warming the ATF. But, did he do any testing where the ambient temperatures were near or below freezing? Also, 150 degrees F. is the minimum temperature that ATF should operate; ideally, it should be operating in the 175-200 degree F. range. Most people who have done ATF temperature testing using the bypass (that I've read) have stated temperatures in the 150-160 degree range, but I haven't seen any at or over the 175 degree range. I don't think that's a big issue, especially in warm weather. My concerns have always been what those temperatures are and the warm-up time of the fluid in extremely code weather. Here's a good link on ATF temperatures:

http://www.digi-panel.com/trannyoil.htm

If you are interested in the radiator foam seals, refer to the following part codes in the diagram link below: 21488Q, 21488QA, 21488QB and 21497L.

http://www.nissanpartszone.com/Page_Pro ... entsNo=214

smj999smj wrote:But, did he do any testing where the ambient temperatures were near or below freezing?

My thoughts exactly when I read this last year. Its -26C here today.

I haven't instrumented my vehicle up to this extent, but have done the 'feel' test on my air/oil cooler after 10 minutes of highway driving in these temps. It is warm to the touch, which in these temps satisfies me enough to say the trans is 'warming up'.

Even at 160$ that's still not that bad for a new radiator. I will start looking into that this weekend along with my other projects. Thanks a lot for the tips.

And on the ATF warming, living in Florida I don't really get exposed to very cold weather. The coldest it's gotten down here is about -2C. Though, I'm sure it's still a bit of a concern. I guess I was just more worried about toasting my transmission from heat.

I'll be in Orlando next week! Thank God, its freakin' cold here right now.