# 2006 Pathfinder overheating



## #Jupiter123 (Feb 1, 2018)

new radiator and thermostat. Still overheating at idle to a point AC stops blowing cold. Overheated @ highway speed also. Electric fan runs. Could it be a bad fan clutch? How do I chech the fan clutch? 
Thanks


----------



## smj999smj (Jan 1, 2006)

Most of the time the fan clutch fails on these engines, they stay locked and make a lot of noise, which wouldn't cause an overheat. Also, at highway speeds, the mechanical fan is not needed to cool the radiator as the forced air moving through the cores is sufficient. Overheating only at low speeds or idling would be consistent with a bad fan clutch.
A couple of things I would check first. The pressure cap on the coolant system is located on the coolant reservoir, not on the radiator like on older Pathfinders. Check the radiator cap and make sure there is no thermal spring on it; there should only be a ring-shaped gasket on the bottom side of the radiator cap. The reservoir cap should have a thermal spring on it. So, make sure the caps were not switched between the two and make sure you have the correct-type cap on the radiator.
Check the automatic transmission fluid for signs of coolant contamination. The trans coolers located inside the bottom radiator tank on these vehicles are notorious for having a seal fail, causing coolant cross-contamination. This defect was found in the original, Calsonic-made radiators, not aftermarket replacements. The original radiators would have a Calsonic sticker on the top tank of the radiator, usually with one of the following part numbers: 21460-EA215 or 21460-EA265. If you have either of these radiators, regardless of whether the cooler has failed or not, it's a good idea to replace it, or, at least re-route the trans cooler hoses to bypass the radiator's cooler and utilize just the factory-installed, auxiliary trans cooler in front of the A/C condenser. 
Next, make sure the fins of the A/C condenser are not bent or plugged with debris, preventing air flow through the condenser and radiator cores. Also, make sure there are not leaves built up between the radiator and condenser cores, blocking air flow. 
Make sure the coolant level is full; I know this is common sense, but you'd be surprised how many people have complained about overheating or no heat, only to find the coolant was low.
Make sure the air is purged from the system. Jack the nose of the vehicle up as much as safely possible and start the engine. Set front and rear heaters to maximum heat. Run the engine at 2500-3000 RPM for at least 10 minutes and make sure good heat is coming out of the vents. Turn off the engine and lower the vehicle.
If you still have overheating problems, it's possible you could have a blown head gasket, but I would suspect a restricted or clogged radiator, first. I have heard of a few that have caused overheating on these vehicles. The good news is that you can get an aftermarket radiator for under $100 from Rockauto.com. The bad news is that this isn't the easiest radiator to replace. Book labor time is 3.0 hours. Most of the problem is the side brackets on the radiator getting hung up on the hard lines to the A/C condenser, which shares the same lower mounting as the radiator.


----------



## #Jupiter123 (Feb 1, 2018)

I followed your suggestions step by step. 
1. New caps for the radiator and coolant resevoir from Nissan Genuine Parts. Thermal Spring 1.1 CAP ASSY-PRESSURE I put on resevoir. CAP-SEAL I put on radiator there is a 1.1 on the orange WARNING sticker. 
2.No Calsonic Radiator sticker on radiator tank. Pulled transmission dip stick and the fluid didnt smell burnt or appear to have coolant contamination. The fluid appeared to me to be amber in color not red like the tranmission fluids I have been used to seeing. Nissan may have special fluid. Fluid is a little low what should I do about adding transmission fluid not knowing what type fluid is in the transmission now? This Pathfinder has 215,000 mi. and I hate dropping the trans pan or tearing something down if it ain't broke.
3. Fins are good and no blockage on condenser or radiator cores.
4. Coolant level full. Jacked up the nose twice, ran engine 2500-3000 RPM each time to purge air. Great heat both times from vents. Owner before me bypassed the rear heater under the hood due to a leak, could this be a problem? 
Previous owner said the thermostat was replaced, but I don't know. How hard is it to check and/or replace?

A/C works good until temp rises to the top edge of the normal temp. operating range. then A/C shuts down until the engine cools to midway point of temp gauge. The temp has never climbed out of the normal operating range into the danger range. but I havent driven it in the summer yet. Previous owner got tired of this overheating issue so I picked it up. I drove it on the highway the other day and the gauge needle was almost out of normal range into hot range. At idle temp seems to be normal unless A/C is on then temp starts to climb to hot. Thanks for your help and suggestions in this matter


----------



## JimK (Oct 14, 2019)

I am having the EXACT same symptoms on my '05 Pathfinder. Replaced radiator, fan clutch and caps. Wondering if you resolved the problem and how.


----------



## Tragan (Jan 28, 2021)

If anyone comes across this with the same symptoms then stop and ask yourself which thermostat did you buy and put in? If your answer is one from AutoZone or advanced etc... There is your problem these motors do not like aftermarket thermostats . Even tho most owners think there car is running fine because the temp gauge is very close to normal. I went through five aftermarket thermostats before finally figuring it out. BUY OEM FACTORY THERMOSTAT FOR REPLACEMENT . SOLVED MY CARS PROBLEMS AND RUNS NORMAL 180 TEMP INSTEAD OF UPWARDS TO 220 OR A TAD MORE. I red on the farms at the vq40de engine does not like an aftermarket thermostat. Well folks it's true they don't


----------

