# 2008 Pathfinder Transmission/Radiator Bypass



## ToneSurfer (Mar 17, 2015)

Trying to avoid the transmission fluid/antifreeze mixing problem due to failed radiator core. I've seen posts on how to bypass it, but they are for the earlier year models.

I have a 2008 Pathfinder that has the external transmission cooler located on the drivers side front of the radiator, in addition to the internal radiator pass-through.

The hose routing on this year model is different that any of the walk throughs I've seen on the internet describing how to bypass the radiator portion.

Can anyone describe how to do the bypass on this model?


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## smj999smj (Jan 1, 2006)

It's easy. You'll need about 3' of 5/16" automatic transmission cooler hose (you will cut this down to size), two 5/16" vacuum caps, a plastic tie strap, and some miniature hose clamps (I prefer to use the Nissan constant tension clamps that came original from the factory). 
Remove the front skid plate to access the cooler hoses. You'll see the two, metal cooler lines on the right side of the vehicle, near the oil filter (and looking up from the bottom of the vehicle). The hose that runs on the passenger side of the radiator to the metal cooler line is left alone. Looking at the driver's side of the radiator, near the bottom, you will see the cooler hose has a barbed fitting in it. Essentially, you are running your new cooler hose from that fitting to the other metal cooler line, near the oil filter, discarding the old hose. I used the tie strap to secure the new hose a little better. I used a little compressed air to blow the trans fluid out of the radiator integral cooler before capping off and clamping the fittings. It's pretty much common sense once you get eyes on it and see what's going on. You probably won't lose enough ATF to have to top off the system, but it would be a good idea to check and be on the safe side after you're done.


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## ToneSurfer (Mar 17, 2015)

Awesome. Sounds easy enough. I looked around without pulling off the skid plates and kinda "thought" that's how it might be done. But better safe to ask. Thanks for the quick answer!

It's in the shop now for the timing chain tensioner issue. I asked for a price on how to do this simple job and they acted like they had never heard of it before - but was happy to talk about adding a secondary cooler.....


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## smj999smj (Jan 1, 2006)

The factory-installed, auxiliary cooler is sufficient enough for cooling the fluid, unless you are towing. If you tow, I would recommend you replace the radiator with an aftermarket unit. A liquid-to-liquid cooler is far more efficient than an air-to-liquid cooler. Plastic tank radiators, like the original, can be found on Ebay for well under $100. If you want to upgrade to an all-aluminum radiator, Stillen has just started selling them for $350. The one thing you do lose with bypassing the radiator cooler, other than it's cooling benefits, is the ability to warm the fluid and maintain it in the preferred range of 175-200 degrees F. Maybe that's not a big issue, but something you would want to consider if you live in an area that sees extremely cold weather.


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## ToneSurfer (Mar 17, 2015)

No towing, ever, and live in Texas, I think it will be warm enough on it's own :0


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## ToneSurfer (Mar 17, 2015)

Bypass completed. Was easy. All the parts I needed I was able to find at O'reilly Auto parts.

3 feet of Gates Corporation 5/16" Trans Cooler Hose.
5/16" Vacuum Caps.
Some 5/16" hose clamps (glad I got these).

Note: The outside diameter of the new hose was a tad smaller than the factory hoses, even though the inside diameter of each was 5/16". I didn't trust the factory clamps to be tight enough so I just used ordinary hose clamps.

Duct tape, zip ties, and compressed air I already had on hand.


Took my time. Used an orange juice bottle to collect any fluid that came out of the hoses/radiator.

Started with the factory barb hose connection on drivers side. Pulled the hose apart, and quickly stabbed an vacuum cap on the barb. Then dunked the hose (still connected to radiator on other end) into juice bottle.

Took off hose from radiator and stabbed another cap on.

Then onto the passenger side. Disconnected the connection by the oil filter. Stab on vacuum cap and then dunked hose into juice bottle.

Then got a can of compressed air (used to clean computers) and a small bit of hose I had laying around, jammed it onto the drivers side of the radiator and blew out whatever fluid I could from the radiator core component.

Disconnect the last hose on the radiator and stabbed on another vacuum cap.

So now everything is capped off, very little drips, and most of the fluid collected into the juice bottle.

Mocked up the cooler hose and cut it to length. Then put it in place between the oil filter size connection and the driver side barbed fitting. If you are quick enough pulling caps and stabbing on hose you won't spill anything else.

Tightened up the hose clamps on everything.

Run the engine a bit, check for leaks. Test drive, and check for leaks again.

Put some duct tape on the hose where it looked like it could get abrasion from a few sharp pieces of plastic on the fan shroud and then zip tied it in place.

Buttoned it all up. Done.


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## Sid79 (Aug 4, 2015)

*ToneSurfer* how is the Bypass working for you. I have been thinking of doing this to my pathfinder 2008 model.Do you have any pic of it so that it will be a bit easy to mess up the things.


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## Cusser (Apr 16, 2004)

*If you have automatic V6 2005-2010, better do something about this NOW !!! * I've read a lot about this radiator mixing issue, and none of that is good !!!


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## smj999smj (Jan 1, 2006)

I replaced the radiator in my 2006, but did the bypass in my 08 Pathfinder and haven't had any issues. If your radiator top tank has a Calsonic part sticker with the part number ending in "-EA215" or "-EA265," you have the original radiator which is prone to the cooler failure issue. If you do, then do something rather than wait for the possibility of it failing. It's not worth ruining a $5000 automatic transmission.


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## Sid79 (Aug 4, 2015)

smj999smj - My radiator part sticker is not readable now. Do you have any pic of 2008 bypass as i am not sure which way to do it with reading only.


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## smj999smj (Jan 1, 2006)

It'll be pretty apparent what you have to do once you get a look at it with the skid plate removed. The link below shows pictures of a 2008 bypass, however he did it by joining the hoses together on the driver's side, whereas I installed a new section of hose (less clamps and looks a lot neater). 

The Nissan Path :: View topic - another trans/radiator bypass done


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## los420 (Aug 25, 2015)

Ok i did the bypass now I have a leak some were from the transmission it didn't leak before did anyone have this problem


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## Sid79 (Aug 4, 2015)

Smj999smj Can you tell the size and length of hose you used as i am not able to get hose connector of this size here in canada so i was thinking using a single hose.



smj999smj said:


> It'll be pretty apparent what you have to do once you get a look at it with the skid plate removed. The link below shows pictures of a 2008 bypass, however he did it by joining the hoses together on the driver's side, whereas I installed a new section of hose (less clamps and looks a lot neater).
> 
> The Nissan Path :: View topic - another trans/radiator bypass done


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## smj999smj (Jan 1, 2006)

I used 5/16" (or 8MM) transmission hose.


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## Papasmurf1948 (Feb 6, 2021)

Question if I install a new radiator in my 08 Frontier LE V6 will it solve my problem or will I still need to do this bypass?


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## smj999smj (Jan 1, 2006)

Papasmurf1948 said:


> Question if I install a new radiator in my 08 Frontier LE V6 will it solve my problem or will I still need to do this bypass?


It'll solve the problem. The issue only existed on the original, factory-installed radiators.


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