Radiator Replacement vs. Bypass

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65Fastback
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Postby 65Fastback » Wed Oct 06, 2010 8:41 am

Check this out, everyone should read this and I just e-mailed this to my local Nissan Dealership.


To address the reliability issue with Nissan's radiators in the R51 Pathfinder, I have found a solution I would like to move forward with.

Radiator.com 1-800-248-8720 (Nathan x 215) has a replacement radiator with a less than 5% failure rating vs. the current 27% radiator failure my car has. Their tech rep for the company who tested all the Nissan radiators returned to them said there were inferior metals used in the transmission line inside the OEM radiator. Over the course of a short time, the expansion and contractions with regular use of the radiator would cause the failure at the weld and line causing the contamination and transmission failures.

The cost for the new improved radiator they have is $128. http://www.radiator.com/nissan-pathfind ... ngine=4.0L, 244ci, V-6

If I were to order it and bring it to you, then a lifetime warranty comes with the radiator. They told me if you order it, then it will cover any issue should the radiator coolant leak into the automatic transmission then Radiator.com would cover it because there was a certified mechanic at the dealership that installed it.

I would like to move forward and have the radiator replacement ordered through Radiator.com and have a coolant and transmission flushed at the same time. I would like to see if Thursday the 14th will work for me to bring the car in.


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Tech
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Postby Tech » Wed Oct 06, 2010 8:49 am

I've hear the warmer/cooler debate before - i'm a cooler believer. Any external cooler (like those for "towing packages") are definately coolers. I personally like the long finned bar type and like it set back a bit in the opening where guys are now putting driving lights. I don't howver tow boats just trailers. You can get all different shapes and sizes to fit whatever application you have (fog lights/driving lights or whatever in the way), though i've never worried about having them "blocking" a bit of the rad. I prefer to think of it as a cheaper first line of defense from having something hit the rad. I don't offer the bypass as a service but work on lots of vehicles that have done it.....no issues yet, even with no additional cooling.

skinny2
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Postby skinny2 » Wed Oct 06, 2010 9:08 am

Have you seen any bypass work done on the '08+? These have different positions for the inlet/outlet and it's not as simple as some of the earlier models. Just curious if you know of a good way to bypass the '08 and not compromise the lines, connections, etc.

Kidd_Funkadelic
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Postby Kidd_Funkadelic » Wed Oct 06, 2010 9:39 am

I've been following this pretty closely since I just bought an '05 PF in May. I did the bypass for piece of mind but have seen the XTerra forum post about the very tangible affect the radiator has on the fluid temps.

I find it interesting though no one has mentioned that according to the manual, there is an idiot light for transmission fluid temp if it were to hit a dangerous level. So my thought is if I don't plan to tow or offroad on a frequent basis, I'm not going to worry about it. If the transmission got into dangerous territory, the light would tell me to pull over and cool it off for a bit...

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Tech
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Postby Tech » Wed Oct 06, 2010 10:06 am

I have yet to see a single vehicle, even with slipping/dystroyed trans overtemp. Not just pathfinder xterra, but any model. Granted they don't have trailers and stuff attached when I get them, but no codes either. I'm personally not concerned at all about trans temp. The solenoids don't really generate much heat, the clutches and drums/bands only do when they're shifting, not really when they're holding.

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JAHBLESSINGS
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Postby JAHBLESSINGS » Wed Oct 06, 2010 10:19 am

tech i think you misunderstood my post. i was asking if the radiator only cools the coolant and warms the atf, right?

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Budrbean
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Postby Budrbean » Wed Oct 06, 2010 1:42 pm

Kidd_Funkadelic wrote:I've been following this pretty closely since I just bought an '05 PF in May. I did the bypass for piece of mind but have seen the XTerra forum post about the very tangible affect the radiator has on the fluid temps.

I find it interesting though no one has mentioned that according to the manual, there is an idiot light for transmission fluid temp if it were to hit a dangerous level. So my thought is if I don't plan to tow or offroad on a frequent basis, I'm not going to worry about it. If the transmission got into dangerous territory, the light would tell me to pull over and cool it off for a bit...
I had to drive mine about 30 miles last week with a slipping trans (to the shop) and according to my temp gauge, it got around 250 degrees and almost pegged the gauge. If this idiot light is true, I would sure hope that it would have came on then.

Im in agreement with Tech. I think everyone is freaking out way too much over this. We need to accept the fact that Nissan is not going to fix our problems. Either do the bypass or dont and pay the price when your fluids mix. You arent losing that much cooling capacity by omitting the radiator. If you dont believe me or anyone else, then put a temp gauge on it. The numbers dont lie. 185 or below is very optimal operating temp for a transmission, mine only reads higher than that in 90+ degree stop and go traffic. And I promise you, hooking it up to the radiator will not cool that either. Thinks logically here. A cooler is a cooler is a cooler. Whether its in the radiator or external, it still serves its purpose to cool fluid. I say bypass or pay $4K+ for a new transmission.

4x2
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Postby 4x2 » Wed Oct 06, 2010 9:16 pm

i'm sure the radiator atf cooler is meant for cooling rather than heating. Because how does it provide heat when the thermostat is still closed? By the time it opens the tranny would most likely have warmed up, as they generate plenty of heat on their own. In addition its located at the bottom of the radiator, the coolest part.
I'm planning on just replacing the radiator with a better quality aftermarket one. No point in buying a nissan radiator considering its high defective rate. Doing the bypass may be ok if you're able to monitor the AT temp and make sure that it stays in a safe range, but you sacrifice some performance capabilities. Otherwise you risk losing the transmission prematurely to overheating.

4x2
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Postby 4x2 » Wed Oct 06, 2010 9:24 pm

Budrbean wrote:
Kidd_Funkadelic wrote:but have seen the XTerra forum post about the very tangible affect the radiator has on the fluid temps.


You arent losing that much cooling capacity by omitting the radiator. If you dont believe me or anyone else, then put a temp gauge on it. The numbers dont lie. 185 or below is very optimal operating temp for a transmission, mine only reads higher than that in 90+ degree stop and go traffic. And I promise you, hooking it up to the radiator will not cool that either. Thinks logically here. A cooler is a cooler is a cooler. Whether its in the radiator or external, it still serves its purpose to cool fluid. I say bypass or pay $4K+ for a new transmission.
I'm just curious have you compared the pre-rad atf cooler and post-rad atf temp readings? That will tell you if the rad atf cooler is effective. Since you said a cooler is a cooler, why do you say the rad atf cooler will not cool it?

4x2
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Postby 4x2 » Wed Oct 06, 2010 9:39 pm

Tech wrote:I have yet to see a single vehicle, even with slipping/dystroyed trans overtemp. Not just pathfinder xterra, but any model. Granted they don't have trailers and stuff attached when I get them, but no codes either. I'm personally not concerned at all about trans temp. The solenoids don't really generate much heat, the clutches and drums/bands only do when they're shifting, not really when they're holding.
How high of a temp is consider overtemp? Budrbean had his tranny at 250 degrees is that overtemp? His AT/temp light also didn't come on. I'm sure most if not all AT generate lots of heat when they're slipping, not just shifting, especially under heavy load. That's why when torque converter is locked tranny stays much cooler.
Last edited by 4x2 on Wed Oct 06, 2010 9:51 pm, edited 1 time in total.

4x2
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Postby 4x2 » Wed Oct 06, 2010 9:49 pm

JAHBLESSINGS wrote:tech i think you misunderstood my post. i was asking if the radiator only cools the coolant and warms the atf, right?
I think the only times the radiator is not able to cool the atf, is when the AT isn't generating much heat or the cooling capacity of the radiator is maxed out. Otherwise there should always be cooler coolant at the bottom of the radiator.

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Tech
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Postby Tech » Wed Oct 06, 2010 10:19 pm

I'm not sure what temp triggers the light, but it's way beyond the being terminal for the trans.

I really do like the rad construction other than the cooler. The cores are nice, good fin count, good fit to the condenser. Even with mixed fluids and under-maintained coolant (which turns acidic, enough to actually generate voltage), they haven't failed.

Thats why my vote is to keep the original rad (which you will want to do after attempting to change one - LOL), bypass the cooler and, if you're worried, add an external cooler. That's all i'm saying. IMO this also happens to be the most economical way. You don't even lose any fluids. Get the joint connector, connect the hoses....drive away.

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jspitz
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Postby jspitz » Thu Oct 07, 2010 6:08 am

Tech wrote:... Get the joint connector, connect the hoses....drive away.
I'm sure I'm missing something, but why get the joint connector rather than just re-route the hoses as shown here:
http://www.thenewx.org/forum/showthread.php?t=25955

Thanks, Tech!

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disallow
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Postby disallow » Thu Oct 07, 2010 7:12 am

65Fastback wrote:Check this out, everyone should read this and I just e-mailed this to my local Nissan Dealership.


To address the reliability issue with Nissan's radiators in the R51 Pathfinder, I have found a solution I would like to move forward with.

Radiator.com 1-800-248-8720 (Nathan x 215) has a replacement radiator with a less than 5% failure rating vs. the current 27% radiator failure my car has. Their tech rep for the company who tested all the Nissan radiators returned to them said there were inferior metals used in the transmission line inside the OEM radiator. Over the course of a short time, the expansion and contractions with regular use of the radiator would cause the failure at the weld and line causing the contamination and transmission failures.

The cost for the new improved radiator they have is $128. http://www.radiator.com/nissan-pathfind ... ngine=4.0L, 244ci, V-6

If I were to order it and bring it to you, then a lifetime warranty comes with the radiator. They told me if you order it, then it will cover any issue should the radiator coolant leak into the automatic transmission then Radiator.com would cover it because there was a certified mechanic at the dealership that installed it.

I would like to move forward and have the radiator replacement ordered through Radiator.com and have a coolant and transmission flushed at the same time. I would like to see if Thursday the 14th will work for me to bring the car in.
5% is still horrendously high. I work in the Heavy-duty vehicle industry. The industry accepted failure rate for aluminum radiators is LESS THAN 1%. 5% is ridiculously high, 27% is far past recall levels.

I would doubt that the failure rate is anywhere near 27%. Not sure what the threshold is to report to NHTSA, but its far lower than that. And if the issue went to NHTSA, we'd be seeing a recall already.

I also don't buy in to the J-Matic corrosiveness idea. If it was corrosive to the tube in the rad, we'd be having more issues inside the transmission.

What is more likely is a lack of coolant maintenance. Coolant that is not changed regularly becomes quite acidic, and will eat the tubes in the rad not through corrosion, but erosion due to the high coolant flow. It would also depend especially on how the trans-cooler tubes are welded into the radiator. Acidic coolant eats weld flux, erego leaks!

Maintain your coolant, and I doubt you will have issues. Also, you need to ensure that you use borate free and silicate free coolant, as provided by Nissan. I personally use Honda Premix coolant in my 05 Pathfinder. Hondas are even more sensitive to old/incompatible coolant. I've heard of many people topping up with regular Prestone coolant and having water pump issues in very short order.

t

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pawjr74
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Postby pawjr74 » Thu Oct 07, 2010 8:01 am

Another thing to remember is to only use distilled water in the cooling system. Never use tap water or hose water.


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