'03 QX4, Weak in town, no aux fan for A/C?

[Mike W.]

Coming from the BMW world I'm used to always seeing an electric Auxiliary fan in front of the A/C condenser, and in those cars it's absolutely crucial for good performance, if it's not there you'll be sweating in town. So far in my limited time in 100F+ in the QX4 the A/C seems to take quite a while to really start working, especially in town. Fine when it does get going, but it takes a while. So today I'm doing my first oil change in it and much to my surprise there was no Aux fan! (yeah, still on the steep part of the learning curve) Lots of room up there to work with, does anyone do this or am I just nuts. (don't answer that question) I also have noticed there is an unused fuse location for something like A/C fan. (I can't remember the exact name)

Good idea, bad? Is A/C normally kick a** in town or a bit on the weak side?

[AlanAZ]

I just went through a week of 115F+ days, and I thought the A/C system worked fine around town. It could be that your system is low on refrigerant. A year ago, mine wasn't cooling as it normally did and had it recharged, it was down by 8 oz (out of 36? oz capacity.) And make sure the clutch on the fan is OK (although you'd normally see some engine overheating also.)

[Mike W.]

I just went through a week of 115F+ days, and I thought the A/C system worked fine around town. It could be that your system is low on refrigerant. A year ago, mine wasn't cooling as it normally did and had it recharged, it was down by 8 oz (out of 36? oz capacity.) And make sure the clutch on the fan is OK (although you'd normally see some engine overheating also.)

Hmmm, given your location you ought to know. The vehicle is new to me although there is a receipt for A/C work which said the system had previously been overcharged. I guess I'll leave it for now and see how it goes.

[Qxx4]

i live in dubai so temps here reach about 55 Celsius and the my qx4 is GCC Spec which came equipped with a electric fan on the condenser which helps a lot in the hot weather

[atraudes]

In the albeit handful of 100+F days I've seen here the A/C has never been lacking, FWIW. I did have a refrigerant leak in the hose that runs across the engine from the compressor to the cabin, so thanks to that repair I know the A/C is working they way it should. You can either get the system properly charged and they can add a dye to make the leak very obvious, or you can wipe down all connections in the A/C system really well and just keep an eye out for wet or dirty spots.

[Mike W.]

I'm of two minds here, first A/C principals are the same regardless of make, and I've never heard of a car having too much condenser/heat transfer. On the other hand, maybe it's ok as is, I'll wait and see how it goes on vacation in the desert soon. It was just something that raised a red flag for me.

[bryanmenard]

Some people have added electric fans on here, for various reasons. I used to have a Volvo with very weak A/C and I had an electric fan that I would manually turn on from the driver's seat when approaching red lights and in stop-and-go-traffic. It worked like a champ. My experience has been European cars have weak A/C but that's not always true. I know in my Volvo, it was! No, I've never had any issues with either of my QX4's

Get the A/C system looked at by someone competent and make sure you're not over or undercharged. The A/C should be evacuated and refilled with the precise amount of refrigerant and oil called for. It's precise. Don't go anywhere with these clowns using cans and gauges hanging from the hood in the driveway saying "oh yeah, it's running cold now." RUN. Go to a legitimate shop that's weighing everything out. That's the only way to do it: PRECISELY.

NOTE: There were changes in the A/C system on the R50 Pathfinder and QX4 in 2002-2004 compared to the 1996-2001. I own both a 2001 and a 2003. The only difference from the driver's seat is the 2001's Auto Climate only goes down to 65 and, in the 2003, it goes down to 60. The 2003 uses less refrigerant (450 grams) than the 2001 (550 grams). The 2001 has a plus or minus of 50 grams and the 2003 must be precisely at 450 grams and is more sensitive to variations (i.e. will cut off if under or overcharged even slightly)

VERIFY the label under the hood, but your 2002 should use 450 grams or R-134A, just like my 2003. Any competent A/C person will look for the capacity.

Having both cars, I'd say my 2003 has the better system. In spite of using less refrigerant, it cools down very quickly and can maintain very low temperatures on the hottest days. The 2001 takes longer to cool down but eventually gets just as cold. Both are in fine shape and I've noticed no degradation in performance as they've gracefully aged.

Under the hood, the 2002-2004 has the same system that was used in the R51 models, with the same capacities. Both cool very well in extremely hot south Texas weather and have been totally trouble free save for a condenser being replaced due to physical damage a couple of years ago in the 2003 model.

[Kev90]

On my Pathfinder the entire AC system minus the evaporator has been replaced with new equipment and it also has a brand new clutch and fan. The original fan had large cracks in it. However this pathy in stop and go traffic has poor AC, once you are moving the A/C is icy cold. I sealed up around the Fan shroud as best I could, but didn't make a noticeable difference. On mine I do have an extra large transmission cooler in front of the condenser that is not helping situation by causing the mechanical fan to pull air through a thicker assembly. I am thinking of mounting an auxiliary electric fan that will run whenever the A/C is on, just need a relay to turn it on when the condenser is running. I am also needing to replace the idle air control valve as it is not working properly, that might help as well. Maybe the idle speed is too low and not allowing the fan to spin fast enough....

[bryanmenard]

I am thinking of mounting an auxiliary electric fan that will run whenever the A/C is on, just need a relay to turn it on when the condenser is running.

It's never a bad idea to add additional fans to any car, especially if you're constantly in stop-and-go traffic. My QX4's never had issues with the capability of the systems but, on my old Volvo, adding that auxiliary fan was a God-send. That car had inherently weak air conditioning and it made a double digit improvement in temperature at the vent when the car was stopped. I loved it. I didn't mess with thermostats or anything. I just put a switch in the center console and, any time I wanted it, it was there. It was great.

[Mike W.]

I'm going to wait a bit, but always looking and looking ahead. Again, I'm used to a different marque and different companies/countries tend to do things differently, but the same principals apply, but I'm concerned about performance, not theory.

There's a huge gap between the condenser and the radiator, well, an inch or so. To me that means it's easier for the engine fan to draw air in from around the condenser than thru it. My thought is also to use a 2 speed fan, relative large, but on low speed, just switched with the compressor thru another relay. The next several weeks will tell a lot.

[bryanmenard]

The next several weeks will tell a lot.

These trucks aren't known for inherently weak A/C. So you're starting with a great platform assuming all is working well.

Good call. Down here, there are quite a few specialized A/C shops who can do custom setups with big, awesome parallel flow condensers, multiple fans, etc. and really do amazing stuff for folks who want more. I wouldn't be scared of modifications (I wasn't with my Volvo) but I haven't seen the need on my R50's yet. Get the truck at her A/C peak and then figure it out is a good idea

[atraudes]

It probably doesn't make a huge difference, but you have a strip of foam between the radiator and condenser at the top, right? I replaced mine with some thick foam insulation from Home Depot when I replaced the radiator and condenser.

[bryanmenard]

If all is perfect on your fill and no leaks, it could be a weak clutch or compressor. It happens. Food for thought

[Kev90]

I just installed two 10" pusher fans on the front of my pathfinder in addition to the stock mechanical fan. Each fan states it pushes 1000cfm. There is probably space for two 12" fans if you wanted larger ones. I wired them to a relay that turns them on when the compressor is running. These have made a noticeable improvement to my A/C in stop/go low speed driving. The rest of my A/C system is in tip top shape. I removed the front grill which made it easier to install, and mounted the center of the fan directly behind the bumper to ensure the weren't obstructing airflow while driving.

[Mike W.]

Well, after 3,999 miles on vacation an auxiliary fan is in it's future. I found performance in stop and go lacking, especially in an hour of stop and go in 100F+ temps due to construction, plus after a while the truck itself heated up and I had to turn off the A/C to cool it down, which it did immediately. I ran into a couple of other situations where it heated up too, both similar, low speed, off road going up a steep hill with the A/C cranking. It never overheated, didn't use a drop of coolant, but the gauge said it wasn't happy. As far as I can tell the fan clutch isn't bad, but it might not be as good as it could be, a new one of those is on order.

So... I've got a 16", very thin fan I think I can squeeze in there and I have the controller for high speed along with a few other things for install on order. A little custom work, but that's the fun part, designing and building not just changing parts.

[Kev90]

I purchased the two fans on summit racing. Cost $35 each. Wish I got some fancier ones as these ones are slightly noisy if you have the windows down. However at the end of the day they make the A/C work much better which was the main plan.