Air Conditioning question

F

fblainen11

New member
I drive a 97 black 4runner in the hot and humid south Louisiana. Actually my wife drives it mostly to work and back and she drives down the Main Street with lots of red lights and slow traffic.

About 4 months ago I replaced my ac compressor. The bearing on the pulley went bad and damaged the shaft on the compressor. So I had to replace. I put a Denso comp in which I was told is the OEM supplier.
While changing it I pulled a vacuum on the system and measured the pressure. Went to lunch with it empty and vacuumed and checked pressure after about two hours. Pressure stayed the same so I figured everything should be good to go.

After filling it with the expensive synthetic stuff my ac worked good.
Now I'm in the heat of the summer and I'm finding that unless I'm at a steady 45mph or higher the ac blows air that is barely cool.

My question is is this normal? I feel like it should be somewhat cool even when sitting or not driving. My fan is working fine. Could my condenser be clogged?
What should I check first? Or is this something that goes along with having this vehicle. Thanks!
 
Register to hide this ad
My 00' blows ice cold in 100% humidity in the mid-90's as I learned last week. Makes my 11' 335 feel like warm garbage....

I am not sure about the A/c system in the runners, mine blows less at idle, but its ice cold so its not a problem. It sounds like the A/C clutch is not engaging, so after checking to make sure the system is sealed tight- no leaks, then I would start looking into the clutch activation and the relay.
 
Do you have an A/C manifold gauge? If so hook it up and tell me the reading as the A/C is running, So i can help you out.
 
Thanks for the speedy response. I do not have a Gauge handy. I will check on getting one or borrowing.

Quick question, if the clutch for some reason is not engaging until higher rpm's can I check this by putting the truck in neutral and revving it to 2500 rpm's for a minute or so? If that's the problem it seems like it would be a decent indicator of that being the problem. I just replaced the clutch with the compressor a few months ago.
 
You can hear whether the clutch engages or not by turning the AC on and off while the ignition is set to on (engine off). Ask some one to hit AC button (while the blower fan is set to any speed) while you are in front of the engine.

You can check the level of Freon gas by looking at the glass window on the AC filter. For this you have to start the 4runner and turn on the AC. if you see form like underneath the glass, you should be OK. If you don't see anything, then it needs gas.

If you decide to recharge gas from the beginning, check the compression of the compressor by holding the small hose "high pressure line" by your thumb (like closing a garden hose by your thumb) while turning the clutch part of the compressor about 180 degrees one time. If there is pressure, you should feel pressure to your thumb, basically you cannot hold the pressure at this time.

Do you clean the AC condenser? I used pressurized water to remove bugs and derbies stuck in the AC condenser. Remember to spray water 90 degrees to the AC/radiator core to avoid damages to aluminum fins.


Let me know
 
Last edited:
fblainen11 said:
Thanks for the speedy response. I do not have a Gauge handy. I will check on getting one or borrowing.

Quick question, if the clutch for some reason is not engaging until higher rpm's can I check this by putting the truck in neutral and revving it to 2500 rpm's for a minute or so? If that's the problem it seems like it would be a decent indicator of that being the problem. I just replaced the clutch with the compressor a few months ago.
Click to expand...

I think the best way to check operation of the clutch is to use a jumper wire from the battery to the clutch. A/C clutches either work or not, they are magnetic, not centrifugal/completely, so jumping it should cause it to hit the pulley and when power is off, the springs pull it back. If the clutch is working, then I think you need to verify the compressor is working, system has proper pressure and Freon/r134, and go from there. If the clutch is not engaging, check the ground, it may be loose causing it to come on and off...
 
If its either going to work or not then it definitely works. Like I said, at a decent speed 40+ its as cold as ice. My question is more about is there anything in particular that would cause it to not be as cold at lower speed. Other than the obvious of less air flowing...
 
See if you can get the A/C manifold gauges. You can fine tune the A/C charge with gauges. Since you are in a humid climate remember to put your A/C on recirculate after it initially cools down. This will help save gas mileage as well as lower demand on the A/C system. Since you get cooler air at speed are you positive the fan clutch is fully engaging at low engine speeds? If the A/C is on for a decent period of time, and the engine is at operating temperature the fan should be at least cycling with temperature variations if not fully engaged. Make sure its kicking out serious air flow and noise! If it doesn't howl and feel like you are looking up the tail pipe of a jet engine the fan clutch may be on its way out. Mine was working fine until the warmer weather came...then it decided to give up the ghost. It still spins at a decent speed, but not enough to cool the condenser like it should. It also works fine if the engine and outside temp is cool, but warm it up and it goes into early retirement. One last thing. Check just behind your A/C condenser and make sure there is foam between the condenser and the radiator. If the foam is missing the air can pass by the edges of the condenser and not through the radiator during low speed operations.

Remember most A/C systems (specifically R-134a) will not achieve more than a 30-35 degree drop from ambient temperature. Thus if it is a 95 degree day outside the BEST yoyu will most likely see is 60 degrees out of the vents. If you use recirculate the system can turn your runner into an icebox eventually, so that is what I always suggest. Let me know if I can help in any way. Good luck!
 
+ 2 on the fan clutch.

Run the A/C at idle at home and check the output temp in the middle vents.
Always check the middle vents because the pass side one should be the coldest being so close to the evaporator and the drivers side one will be the warmest one, be that its the farthest away from the Evaporator.
Then put another fan outside of the grill blowing towards the condenser and check the temp now? Should be some what cooler because the second fan is helping out the other one.
For even a more temp change you can spray a "LIGHT MIST" of water from a garden hose into the grill, onto the condenser, taking away a crap load of heat from the condenser.
We did this experiment at school when I went for auto mechanics years ago. I was amazed how much the water being lightly sprayed changed the output temp inside the car.
 
Okay, going to check all this out this evening.
I'll have to wait on the gauges. I'll take a look/listen at the fan and see how that goes.

Out of curiosity, does anyone know the OEM supplier for fan clutch?
I know aisen makes many parts and I saw a few brands on Amazon.
 
fblainen11 said:
Okay, going to check all this out this evening.
I'll have to wait on the gauges. I'll take a look/listen at the fan and see how that goes.

Out of curiosity, does anyone know the OEM supplier for fan clutch?
I know aisen makes many parts and I saw a few brands on Amazon.
Click to expand...

Aisin makes the OEM fan clutch. I got my replacement from partsgeek.com and it is identical and has been working fine for three years. Partsgeek is very good about specifying what is OES and what is not.

Here is my post on the swap:

http://www.yotatech.com/f2/1998-3-4-auto-4runner-overheating-issue-suggestions-216502/index4.html#post51509656

Here is a good write-up on checking them (not mine, from a BMW board):

Testing the fan clutch:
If you have reason to suspect that the fan clutch is defective, here is the recommended procedure to verify the condition of the fan clutch.
1. Start the car (cold) with the hood open and note if the fan is turning, increase the engine RPM and note if the fan turns faster and the noise increases, if it does, first good indication, if it does not increase speed/noise, clutch is bad and needs to be replaced. (Remember, this must be tested after the car has been off for and extended period, over night etc.)
2. Leave engine running and note if the fan starts to slow down after 2-5 minutes, speed/noise should diminish and even raising the RPM, the fan should not make as much noise as when first starting, if it does slow, this is the second good indication. If speed/noise does not decrease, clutch may be “frozen” and should be replaced.
3. Leave the engine idle and watch the temperature indicator. When normal operating temperature has been reached, some increase in fan speed/noise should be noted, in particular when the RPM is increased. If temperature is fairly stable and the fan noise/speed increases or cycles, third good indication. If temperature indication continues to increase, with no increase in fan noise/speed, clutch is defective and should be replaced.
4. After the engine is at normal operating temperature or above, is the only time that the “rolled up newspaper” test that many people talk about should be performed! Take some newspaper and roll it up into a long narrow tube. Be careful, keep hands and fingers away from the fan while performing this test! With the engine at full operating temperature and idling, take the rolled up paper and insert it on the back side of the fan and try to reach the hub of the fan avoiding the blades until close to the hub. Push the rolled paper at the fan increasing the friction to the hub area of the fan. If the fan can not be stopped easily this is the fourth good indication, if it can be stopped the clutch is defective and should be replaced. Again, this test can only be performed when the engine is at or above full operating temperature.

Testing can be performed in any order but just make sure the conditions during testing are those that are specified for that specific test.
Do not continue to operate the engine if the temperature continues to rise and certainly stop if the temperature approaches “redline”.
Click to expand...
 
Last edited:
I think I remember Durk overheating in the Lincoln tunnel if memory serves me correctly so he replaced his then (may have read the thread on YT). I was inclined to do the same and was not sorry laying down the money for a new one.

OEM (Aisin) all the way.
 
4yotaguy said:
I think the best way to check operation of the clutch is to use a jumper wire from the battery to the clutch. A/C clutches either work or not, they are magnetic, not centrifugal/completely, so jumping it should cause it to hit the pulley and when power is off, the springs pull it back. If the clutch is working, then I think you need to verify the compressor is working, system has proper pressure and Freon/r134, and go from there. If the clutch is not engaging, check the ground, it may be loose causing it to come on and off...
Click to expand...

Old thread but thanks dude, my 3rd gen had this issue and it was a bad ground post on the battery terminal. Problem solved!
 
You must log in or register to reply here.

Members online

Total: 297 (members: 3, guests: 294)

Forum statistics

Threads
278,306
Messages
3,554,045
Members
248,016
Latest member
Advally Service

Share this page

Trending content

Back
Top