Bypassing OEM Radiator on 2005 Nissan Pathfinder
Question:
1 Other than price and size differences in Height and Thickness, whats the difference in heat exchange between the 13503 Class III and the 13611 Class I for use on my 05 Pathfinder 4.0 L with the tow package cooling system? Which one do you recommend the 13503 or the 13611? 2 With the OEM factory supplemental cooler connected in tandem with your 13503 or 13611 can I totally bypass the radiator and do so safely? Many have done this without issue, BUT, ... Nissan Service folks, say NO WAY, put in a new Nissan radiator for $700 to $900.
asked by: Robert M
Expert Reply:
The Derale transmission coolers we sell are intended as a supplemental cooler that is meant to augment the factory transmission cooler portion of the radiator, not replace it entirely.
If you are experiencing the common problem with the radiator leaking causing the engine coolant to contaminate the transmission fluid, your best bet really would be to have the original radiator replaced. I did a Google search using the keywords Nissan Radiator Problem and found that Nissan has extended the factory warranties on radiators on 2005-2010 Frontier, Pathfinder and Xterra models. You might want to contact your Nissan dealer for details.
If the mileage on your Pathfinder places it out of warranty coverage, going with an aftermarket replacement radiator/cooler combination would be the best way to go. (I would love to sell you some products, but I am more interested in getting your vehicle fixed correctly and the long term reliability of the repair.)
I found several reasonably-priced options online. You can then install an aftermarket cooler to provide supplemental cooling.
If you are determined to bypass the OEM transmission cooler, be sure to plug the factory inlet and outlet in the cooler to prevent leakage. Choose the largest, most efficient cooler that will fit in the available space directly behind the grille. The # D13504 would be a good choice, assuming that its 11x12x7/8 inch size will fit in the available space. Monitoring your transmission fluid temperature going forward will be crucial if you go this route. I would highly recommend installing a Remote Transmission Filter Kit with Temperature Gauge, part # D13091.
I have linked you to some helpful articles about transmission coolers.

Products Referenced in This Question
Derale Remote Transmission Filter Kit w/ Temperature Gauge
- Accessories and Parts
- Transmission Coolers
- Filter
- Derale
more information >
Derale Series 8000 Plate-Fin Transmission Cooler Kit w/Barb Inlets - Class IV - Efficient
- Transmission Coolers
- Plate-Fin Cooler
- Full-Size Truck
- SUV
- Standard Mount
- 11W x 12T x 7/8D Inch
- With 11/32 Inch Hose Barb Inlets
- Derale
more information >
Product Page this Question was Asked From
Derale Series 9000 Plate-Fin Transmission Cooler Kit w/ NPT Inlets - Class I -Extra Efficient
- Transmission Coolers
- Plate-Fin Cooler
- Car
- Standard Mount
- 11W x 3-7/8T x 1-1/4D Inch
- With 1/2 Inch NPT
- Derale
more information >
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