# Pathfinder overheats



## nissanjet52 (Jul 1, 2012)

Hello, 

I'm in need of help.

My 2001 Pathfinder keeps over heating.

The only thing I can do to keep the temperatures down is to turn on the heat full blast, speed has no effect. Standing still or going 70.

I cant afford to take it to a garage, my brother said he'll help with the labor.

Thanks,
Christina.


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## smj999smj (Jan 1, 2006)

Well, it could be the thermostat (try to use a genuine Nissan thermostat when replacing, if possible). If driving at highway speeds has no affect, it's likely not the clutch fan. If there's an electric auxilary fan, make sure that's working. Make sure there is no debris or blockage of airflow throw the AC and radiator cores. Obviously, make sure the coolant level is "full." It's possible to have a clogged or restricted radiator, but I don't see a whole lot of them on late model Nissans unless there is a lot of neglect on the part of maintenance. Other than that, there could be a blown head gasket, but that's jumping the gun at this point.


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## captrailer (Aug 17, 2009)

If you have > 100 000 kM (62137.12 miles) then replace the radiator, even if there is no crud, discoloration in the fluid. There is some odd chemistry at work here; this is what I did a few years ago and after checking/replacing the items smj999smj posted about. You can spend the time/effort to do all those obvious things, but I highly recommend replacing the rad and save yourself a bunch of time.


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## nissanjet52 (Jul 1, 2012)

captrailer said:


> If you have > 100 000 kM (62137.12 miles) then replace the radiator, even if there is no crud, discoloration in the fluid. There is some odd chemistry at work here; this is what I did a few years ago and after checking/replacing the items smj999smj posted about. You can spend the time/effort to do all those obvious things, but I highly recommend replacing the rad and save yourself a bunch of time.


Thanks,

We've been bouncing from thermostat - radiator - water pump.

The pathfinder has 105,000 miles on it.

I can drive it for about 10 miles in 90 degree weather with the A/C on full, then the temp slowly starts to creep up, like I said i can turn off the A/C and put the heat on and the temp maintains or may drop a little.

Is there a way to test the radiator before we stick a new one in there. Maybe check the temp difference between the top and bottom hoses?

Christina.


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## captrailer (Aug 17, 2009)

I'm not aware of any test for the radiator to reveal the odd chemistry I spoke of. I experienced the overheating problem too after towing my travel trailer in ~30 C (86 F) weather on the highway after 5-10 min; this was all 3 years ago. 

I did replace the thermostat, checked the clutch fan, and the rad & A/C cores for air flow blockage and re-topped up the coolant with the proper mixture. I even considered replacing an alleged second thermostat near the rear of the engine. After an identical road test mine was still overheating, but only while towing my trailer. After much reading, mostly in this forum, I decided that replacing the radiator was my only real option. The most convincing story was from a mechanic in the racing industry who tore his engine apart at one point in search of the problem. In the end for him the replaced rad solved his and my issue.

Sorry I don't have a link to the fellow, but it was from about 2008.

BTW I sympathize with your situation, as I had the same problem as you with my first car, but mine didn't have A/C - it was a convertable - and driving that around in the hot summer with the heat is no fun at all.


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## smj999smj (Jan 1, 2006)

Radiators can be flow tested, but for what you can purchase a radiator for these days, it's not really worth it. Why pay $30-40 to flow test a radiator when you can purchase a brand new, aftermarket for $90-150? If you have an infrared thermal reader, you can use that to test the radiator core temps.


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## LvR. (May 26, 2010)

smj999smj said:


> Radiators can be flow tested, but for what you can purchase a radiator for these days, it's not really worth it. Why pay $30-40 to flow test a radiator when you can purchase a brand new, aftermarket for $90-150? If you have an infrared thermal reader, you can use that to test the radiator core temps.


+1

Measure the inlet and outlet temperatures on the radiator hoses with an IR temp reader while the fans are running full speed and engine at around 2500rpm - that is the absolute easiest way to see if the rad is doing anything useful - you expect around 15C+ difference.................


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## nissanjet52 (Jul 1, 2012)

captrailer said:


> I'm not aware of any test for the radiator to reveal the odd chemistry I spoke of. I experienced the overheating problem too after towing my travel trailer in ~30 C (86 F) weather on the highway after 5-10 min; this was all 3 years ago.
> 
> I did replace the thermostat, checked the clutch fan, and the rad & A/C cores for air flow blockage and re-topped up the coolant with the proper mixture. I even considered replacing an alleged second thermostat near the rear of the engine. After an identical road test mine was still overheating, but only while towing my trailer. After much reading, mostly in this forum, I decided that replacing the radiator was my only real option. The most convincing story was from a mechanic in the racing industry who tore his engine apart at one point in search of the problem. In the end for him the replaced rad solved his and my issue.
> 
> ...


I feel bad for the guy that had to tear his engine apart to find a bad radiator....

You were right, the radiator was the main cause of the problem. The fan clutch was on its way out as well. We replaced the clutch after testing it and seen an improvement, the car lasted twice as long before it started getting hot.

Then tested the radiator with an IR gun, it showed a 20 degree difference. My brother replaced the radiator and the problem is gone.

Radiator was $160 Autozone
Fan clutch $56 Advance Atuo

Thanks for your help!


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## LvR. (May 26, 2010)

nissanjet52 said:


> I feel bad for the guy that had to tear his engine apart to find a bad radiator....
> 
> You were right, the radiator was the main cause of the problem. The fan clutch was on its way out as well. We replaced the clutch after testing it and seen an improvement, the car lasted twice as long before it started getting hot.
> 
> ...


Congratulations are in order, but I must say I am surprised you had to replace the radiator too with a 20C differential present - do us a favor and post the "after rad replacement" current temp differential* under the same conditions *for future reference please


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## nissanjet52 (Jul 1, 2012)

LvR. said:


> Congratulations are in order, but I must say I am surprised you had to replace the radiator too with a 20C differential present - do us a favor and post the "after rad replacement" current temp differential* under the same conditions *for future reference please




I should have mentioned it was a 20F difference, not 20C. I will try to post the new temp difference today.

Chistina.


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## captrailer (Aug 17, 2009)

Well, I'm glad the overheating problem has been fixed, and I would have to agree with the posts by LvR - great test setup; and 20 F (11.1 C) temp diff is not all that much. It would be very nice to have the after replacement temp diff.


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## nissanjet52 (Jul 1, 2012)

Ok, sorry it took so long to get back to you guys. My brother has been busy at work.

With the new radiator there is a 37F temp difference measured at the hoses where they meet the radiator (same area the first temps were recorded)

The temp is staying steady at about the 1/3 mark on the temp gauge.

Once again thanks for the help!

Christina


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## rosaura (Apr 29, 2014)

*why getting overheat my hissan pathfinder 2006?*

overheating replace thermostat and flush still getting overheating


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