04 Pathfinder Overheating issues

[04Pathfinder]

Hi Guys, I'm new to the forum and looking for some help with my 04 Nissan Pathfinder. It started overheating on a 2 hour trip through hills. I lost power when it overheated as to be expected after not seeing the temp gauge rise. I pulled over at that point.

I let it cool, I filled the rad with antifreeze and water. I drove it cautiously the rest of the trip, this kept happening up hills only. As it got hot I would pull over and let it cool and check the fluid levels, there were a couple times i needed to add rad fluid again.

Took it to the mechanic, they changed the thermostat and another spring loaded pressure part, as well as the rad cap. Its still overheating. They let me know that the issue is something else that that they cant take care of and they said maybe its a really small pinhole in the engine cooling system somewhere as a result of me driving it when hot?

Is what they are saying, possibly true? what would be my next step in fixing this overheating problem. It seems to be okay driving in the city and at low RPMs but nothing more then that.

I must add that I'm a foreigner living in Costa Rica. so I don't have a mechanic here that I trust and I'm not sure there are Radiator Specialists in this country that Ive found yet.

Thank in advance for any advice!

Cheers,
Cory

[smj999smj]

It's possible that it could have a blown head gasket, but that's jumping the gun, IMO. If it only overheats at low speeds or going uphill, you may want to check the fan clutch; if it overheats at highway speeds with little or no load, then the clutch would likely not be the issue as the air being forced through the radiator core would be enough to cool the coolant in the radiator. This brings up another point: make sure there is no debris in front of the A/C condenser core or between the condenser and radiator core that would block airflow...and make sure the fins are not bent over on the cores, impeding airflow. Another possibility would be a restrictive or clogged radiator. A radiator shop should be able to flow test the radiator, but depending on what they charge, it might just make more sense to replace it where you live. To check for a blown head gasket, a cylinder leakdown test could be performed, or a sample of coolant could be sent out to a lab that can analyze it for evidence of hydrocarbons (combustion gases in the coolant).

[04Pathfinder]

Thanks a lot for the reply.

Its only been oveheating at low speeds up hills. If I keep the RPMs down the temperature seems fine at any speed.

Also, My AC and Heat hasn't been working for awhile now.... At one point my AC fan wouldn't shut off at all, fan was running all full time. Then it quite completely, I haven't had that looked at yet, I didn't think it was needed right away.

Could these two issues be related?

Thanks again.
Cory

[smj999smj]

If you are referring to your blower fan for your heat, then no, it wouldn't cause your vehicle to overheat.

[Hooligan]

Cory, Where are you in Costa Rica?
I'm north of Alajuela just off the road to Volcan Poas.

[Hooligan]

I might add that, in my opinion, the stock radiator is an absolute piece of crap. Single pass aluminum with plastic tanks.
Nissan could not possibly have made them any cheaper.
Alot of the mountain roads in CR are 1st and 2nd gear, 3 to 4 thousand rpm with rarified air to cool the radiator.
I've overheated numerous times.
A big improvement, if you're going to keep the car, is one of the aftermarket
all metal, multiple pass radiators. Other than silver or gold, nothing transfers heat better than copper. Brass tanks instead of plastic. It's the way radiators used to be made back before the bean counters took over.

[04Pathfinder]

Thanks for the reply- I live in Escazu area. everything is great in Costa Rica except for buying, driving or fixing vehicles!

[Hooligan]

I never liked Escazu. Too much traffic, too much noise, too many damn gringos. I do most of my own work on the car but, I use a shop in the Heredia area when I get busy. They are well equipped for a local shop with 4 lifts and two alignment bays. They even have a hydraulic tubing bender for custom exhausts. I've seen them doing custom turbo installations. Very reasonable prices on labor.
The specialty shops are there but they don't advertise as much as in the US. You have to find them by word of mouth.