1996 LC A/C warms up at idle

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G

greauxpete

Joined
Feb 7, 2006
Threads
13
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61
Location
Lafayette, LA (Tha Bayou)
Hello,

In the mornings the A/C will blow at 38 degrees (measured at vents). In the afternoons (approx. 90F ambient high "bayou" humidity) the vent temps will only reach 60-65 F especially if it is in stop and go traffic (idle). When I get moving at highway speeds it is not a problem as vent temps drop pretty quickly to around 50F. I susupected the clutch fan - so I did the welding glove test - it looks and feels as though the clutch fan is operating as it should. So I put the hose on the condensor while it was idling and the vent temps dropped another 8-10 or so degrees (form 60F) after dripping water over the fins for about 5-10 minutes. Is it possible that the clutch fan is working but no longer has the necessary air flow it had when new? I am thinking about just ordering a new "blue hub" viscous clutch form Cdan to rule it out, but I hate changing parts without knowing they are past their prime. Any suggestions?
 
There was a discussion about this a long, long time ago. Several other members trucks do this, mine included (1996). If I have to sit still for any length of time, the vent temp goes up significantly. The charge is good on the A/C, everything is working correctly, there is, as you guessed, simply not enough airflow over the condensor at idle. Apparently the overseas moddles with rear air use and electric fan to push some extra air and some members here have added one.
 
Mine does the same. I think it's semi normal.
 
I wouldn't rule out the fan clutch. Do you notice any change in your temperature gauge? When my fan clutch would cut out the temp gauge was just slightly above the half way point, while generally it sits just right below half way. The movement is really small. Do you get the start up roar from the fan clutch? It is an relatively inexpensive preventative maintenance item that is known to fail even if it isn't the problem so you may just want to put in a new one.

Good luck.
 
How clogged is the condenser? With the motor cold spray it with water, then your favorite soap, let it soak then hose it out from the motor side. Clean condenser and radiator fins will make a big difference. 30 degrees drop in vent temp isn't much, it maybe low on refrigerant? If you have the original fan clutch, I would replace it with a blue hub, the old one is on it's last leg and the new one is a significant upgrade.
 
The stock system should keep up with 90F temps with no problems, do you even need A/C in nice weather like that?:D If your going to run it in hot weather a pusher fan will help keep the idle/low speed vent temps down.

https://forum.ih8mud.com/showthread.php?t=51171
 
My 94 is the same.

I think the compressor just does not like the 1fz's slow idle speed. If I tap on the gas I get instant cold air
 
Don't underestimate the power of bugs to reduce airflow, driving through one good bug storm can cause clogging, years of buildup can greatly reduce airflow. Your driving at 70 MPH and hit a bug, the shell and wings dry up and fall off, but the more gooey parts technically known as guts, get blown back into the fins and if the A/C is on they get baked on. I have seen coolers, condensers, radiators, from "more buggier" parts of the country that were totally clogged, hold a light behind them and cant see it.

If you try to remove them with high pressure sprayer or brush the fins will be damaged and brushes just push the carcases back between the fins. Once a year or so I remove the grill, hose the coolers, condensers, radiators, spray them with soap and keep them wet for a half an hour or so, to rehydrogenate the bug guts, then thoroughly rinse them out, preferable starting from the backside.
 
Bought the clutch

Guys, thanks for the good advice.
I went ahead and bought the blue hub clutch from
Cdan (BTW thanks Cdan - I appreciate your help with cost).
I figure even if the clutch is not bad it is time to change it.
If that doesnt decrease my vent temps - I will look into
putting in a auxillary electric fan in front of the A/C condensor
like many have suggested. I hope I dont have to add the aux fan - it sure seems like Toyota engineered the system to work correctly as it was originally designed though. I will post o let everyone knows how it goes... Ordered the PHH kit (silicone) and starter contacts too...
Should be interesting....
 
New Fan Clutch & Starter Contacts

This past weekend I pulled the fan clutch and put in the new "blue hub" fan clutch form Cdan... This was pretty easy - followed the advice of another post: 1- Remove fan clutch nuts with a screwdriver to hold back up while looseneing nuts. 2- Remove the two bolts on the top of the shroud pulled shroud forward and slide clutch and fan out towards the drivers side.
Result: 20 minute job, did not remove any belts, no radiator fins damaged...

I also changed out the starter contacts..
This was not as easy as the fan clutch, but not that bad either...
The hardest part was the initial breaking of the
bolts and getting to the plastic cover that holds the
wire to the starter so I could actually get a wrench
on the nut...

I checked my AC pressures after the fan clutch install and they were low (compared to reported FSM estimates of: 22-36 psi low/ 199-228 high):

Before charging after clutch fan install:

@75F (evening)

Low: 16.5 psi
High: 152 psi

After charging after clutch fan install:

@70F

Low: 35 psi
High: 220 psi

(This seems on the high side)

The real test will be in the 95 degree noon heat to see if the vent temps are lower? I will repost on results...
 
Use recirc mode if you're not already.
 
My did the same thing. LA heat is coming so I went to my wrench for suspension work and check engine light deal. He notice the problem with my idle control valve was not function propely. He took it off and did something to it. Clean it I thinlk. Now I have been sitting in LA traffic for 2 days now, it is cold in this vast parking lot call the LA freeways. It get real cold once I get moving.

Jeff
 
The best thing I ever did for my truck was adding a pusher fan. Not only is the A/C always great, but I have had NO engine temp problems in traffic, 95 degree weather, hill climbing, etc.
 
Well, after adding more R134 my vent temps in really hot and humid weather (95F ~80-90 % humidity) have not improved greatly. My vent temps seem to hover around 60F while at stop lights.. When I get moving around 55 mph for a few minutes the vent temps will drop to 40 F? I really thought replacing the clutch fan would cure this problem but evidently not? If my pressures are correct and the fan is pushing the right volume flow rate of air then what could my problem be? In the morning the vent temps will get to 40F, but in the afternoon and evening the vent temps will only reach 40F-50F if moving ~ 55mph? I will try to check pressures at noon tommorow at maximum ambient temp and humidity - maybe I am overcharged now? This sux...
 
I have found the same issues as you are describing. I have 2 80's, and having just completely flushed one, replacing the expansion valve, condenser and dryer and cleaning the evaporator core, and putting in exactly the right types and amounts of oil and refrigerant it now behaves just like the other one. My temps rise to 70 at idle and only drop to 50 at cruise speeds, but it's a bit hotter here than what you describe. I found that pushing air through the condenser helped quite a bit- see ToolsRUs's post and link earlier in this thread. I used a big shop fan in the garage to test the theory. I'm on a quest for the ultimate electric fan to use, when I find it I'll post in the other thread.

-Spike
 
Spike,


thanks for the input. Atleast I can be pretty sure that I
wont get any gains by going through my system.

When you say you are looking for an electric fan..
I assume you mean an electric fan of the auxillary type
(in addition to the stock engine driven fan).

I read almost every post on electric fans before I changed out my fan clutch and it sounds like there is a JDM auxillary electric fan out there
(~$200) that can be added and gets consistantly good results.
I guess that should be my next project...

It really sounds like the 80 has an underdesigned a/c system - be it the condensor (surface area) or fan flow across the condensor? Either way not enough heat is being dissipated to lower vent temps at idle...
 
Just bought the '91 ('92 interchange actually) Tercel auxillary condensor fan (used by "medtro") with shroud and mounting hardware for 30 bux (used) w/ shipping on car-part.com....

We'll see how this experiment works out....
Medtro said he only had to fab up one bracket and
utilized other stock holes (not necesarily fan holes):

PM from metro:

I didn't get any of the relays and harnesses. I just put in a relay I found in my collection when I did the wiring :).

Toyota used some neat mouting pieces to mount this fan onto Tercel. I would take all of those with the fan to help fabbing your own mouting system.

My mounting system used stock holes, but they are not all stock electric fan holes, as you can see from the pics (that metal plate), I used some of the ATF cooler moutning holes as well.

I don't know the CFM capacity for comparison.

I would do the same mod again on my other 80 if I can get the same fan. I don't like the one from Autozone because I don't like those mounting things going through my condenser.

I hope I answered all your questions, if not please let me know. Have fun!
 
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