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94 nissan pathfinder AC questions

hardbody on Sat May 22, 2010 10:42 PM User is offline

Year: 1994
Make: nissan
Model: pathfinder
Engine Size: 3.0 V6
Refrigerant Type: 134
Country of Origin: Japan

Hello, sorry I don't recall the numbers my tech was getting when he charged my AC but he said they were ok. Anyway, I just bought this truck from a buddy and I had the engine replaced, my mechanic (also my AC guy) said he noticed a leak, we replaced the O-ring and he pulled a vacuum on it and than started to charge the AC, he said the gauges weren't looking right and told me I need to replace the expansion valve. Following week we replaced the expansion valve and cleaned the evaporator. He pulled a vacuum on the system and everything looked good so he started to charge it. I had one of those meat looking thermometers in one of the vents and the air would only drop to about 58 degrees, temp outside was high 80's. He told me to take it for a ride out on the highway to see what the temp would be with airflow, I drove a few miles at highway speeds and the temp dropped to 56 degrees. I use this thermometer in my Nissan sentra which he also worked on and it gets freezing cold usually around 38 to 40 degrees so I trust the gauge, although he did check the temp with an infrared thermometer and it was reading 43 degrees. So no clue on which is actually correct but the air coming out of the vents does not feel like it is 43 degrees.

Noticed today when I am sitting still or driving in traffic the temp will raise but when I start to move quicker temp will drop but the AC air is still not very cold. He also told me there was a lot of dye in the system because when he removed his gauge hose from the high pressure side some dye would come out of the port, he told me there may be a lot of dye in the system and that the dye is heavier than the freon and they don't mix well, he said we may have to take the system apart to flush out all the lines.

want to ask about everything I said and what he told me and also what else can be done to make the air colder?

I live in Florida by the way and today was in the low 90's I need the AC to be as cold as possible

Thanks all appreciate any help you can provide.

TRB on Sun May 23, 2010 10:52 AM User is offlineView users profile

Pressure readings would help.

Sounds like a possible air flow issue. Check the condenser for blockage, bugs bent fins. Check the fan is working correctly.


When considering your next auto A/C purchase, please consider the site that supports you:

mk378 on Sun May 23, 2010 11:48 AM User is offline

Engine driven fans can have a weak clutch, the fan will still spin but not as fast as it should. Did he install the full specified charge by weight? If it was just charged until the high side started getting too high (because of the airflow issue) you won't get good cooling at speed either since it's undercharged. If there is a suspicion of having too much oil, the only remedy is to flush everything out (replace receiver drier) and start over with a new charge of oil.

hardbody on Sun May 23, 2010 2:48 PM User is offline

I know he didn't weigh the freon just went by the gauges, but that is how he did my other car and it works great, the fan seems to be working fine, I mean the truck always runs cool (1/4 from cold on the temp gauge), so from what you said if he charged by using the pressure gauge it could still be low on freon? I don't think the system has too much oil he mentioned there may be too much dye in it which the previous owner may have had done as neither my guy or me added. I'll be going out in a little while and will check the condenser for any blockages.

hardbody on Sun May 23, 2010 6:14 PM User is offline

ok, condenser appears clean, as an experiment I ran the AC with my garden hose spraying on the condenser, the temp at the vents got down to 40 degrees, and the output of the condenser near the drier was also cool, with out the water spraying on the condenser the output of the condenser feels warm. Does this indicate an airflow problem? As I said the engine fan appears to be running right but maybe it's not, and being that when I ran water over the condenser the AC temp was a lot cooler would this indicate the system as far as freon quantity is probably ok?


mk378 on Sun May 23, 2010 6:21 PM User is offline

If it's the fan clutch that came with the truck, it's going to be worn out, you should replace it. It takes a lot more air for the A/C to work well than just to keep the engine from overheating. Does it have electric helper fan(s) on the condenser, and do those work?

Also it's real important to charge by weight, the only way to know how much you have.

TRB on Sun May 23, 2010 7:07 PM User is offlineView users profile

Originally posted by: mk378
Also it's real important to charge by weight, the only way to know how much you have.

Agreed, kind of spinning your wheels if you don't know the refrigerant capacity.

When considering your next auto A/C purchase, please consider the site that supports you:

hardbody on Sun May 23, 2010 8:35 PM User is offline

The engine I just had put in was supposed to be one of those low mileage japan engines, I mean it runs perfect but none of the accessories were swapped over from the original engine. No electric fans just the belt driven one. The freon capacity is on the tag just not sure how much was put in, but from what I said about it cooling better with water running on the condenser, does it sound like the freon amount may be correct just not moving enough air?? I'll look into a new fan clutch.

hardbody on Sun May 23, 2010 8:41 PM User is offline

forgot, is it normal for the condenser to be painted black? I can see some spots where the paint or coating is coming off, was wondering if what ever is on it is supposed to be and whether or not it may be effecting the cooling.

mk378 on Sun May 23, 2010 10:25 PM User is offline

Back in those days, condensers were typically painted black at the factory. But that's mostly for appearance, on newer models they are bare aluminum. You need the electric fans if they have been removed. I think it is two problems, the fan and undercharged. At highway speed the fan doesn't matter and it should be working better there regardless.

hardbody on Sun May 23, 2010 11:33 PM User is offline

thanks, pathfinders never had an electric fan, just the belt driven fan. Was thinking about adding one or two fans in the front but when i was looking at it before I saw that there is no room for any.

hardbody on Mon May 24, 2010 6:36 PM User is offline

I think it may be the fan clutch started the truck today and was watching the fan and even after it warmed up it seems it is still spinning at the same speed, going to replace it and will report back if it helps, thanks all.

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