Heating AC and Engine Cooling

Since most engine cooling fans these days are electric, they can (and will) run even with the ignition off and the key removed. This happens frequently after being run, and the vehicle senses that it needs to cool things down, so it will engage the fan automatically.

Need to know what model you have and the engine size to be sure. Also if it has rear A/C system also. You can get the information you are looking for on the link below. Just click on the "Find Your Car's Low-Side port" it will take you to the the Refrigerant & Lube spec's also.

The sensor is located under the upper rad hose Directly below the hose is a sensor with 1 wire to it That is for the gauge Just behind and down from that is a sensor with 2 wires This is the fan sensor

There is a filter/strainer screen on most AC liquid lines between the condenser and indoor evaporator coil. This strainer is probably stopped up and needs to be changed.

You may have a faulty coolant temperature sending unit. This is just a sensor that tells the computer, and your dash guage, how hot the engine is. It's possible your engine is running in exactly the temperature range that it should, but the sensor is telling your dash guage that it's too hot, and causing you to worry. You probably have more than one, so consult a manual or your mechanic before trying to replace it/them. If this doesn't solve the problem, another thing to do is flush your coolant system. You may actually want to do this first, since it will be cheaper than replacing sensors, and it really should be done anyways just as a precaution around that mileage. Take care of your Toyota, and believe me, it will serve you reliably for a very, very long time.

no it is not their is a problem in the cooling system. check the fan belts to see if they're tight check the water pump to see if you can wiggle it or is there water coming from it are any of the hoses bad check by squeezing them is the radiator clogged check by removing both hoses and run water in the top of the radiator where the cap is to see if you get water out the bottom hose. If all this checks out put a pressure test on the cooling system

bad relay

It is possible that when freeze plug blew vehicle overheated and caused high pressure in the a/c system resulting in loss of refrigerant charge

because you have too many dead babies in your air conditioner tank

The sensor could be defective from factory have it checked at auto zone? Or you might have a bad relay. Had the same problem today. Replaced the relay which is located on the driver side engine compartment fender well. Cost: $21.78 Fan cycles on as required depending on engine temp.

How do you add freon to a 1999 Honda Passport

Around 2 to 4 mpg are saved, depending on the engine size, when the ac compressor is not turned on but that is if your sitting still in your car while it idles.

When you are driving with your ac turned off but have the windows down for outside air, the aerodynamics (how well your vehicle slices through the air) of the vehicle is altered because air is coming into your windows and the back window of your vehicle acts as a parachute so your engine still has to work hard to overcome the wind drag.

Ultimately, I suggest that you use your ac while driving because the compressor and wind drag both affect the mpg about the same amount, but at least you will be cool.

If your compressor is worn out but working, it puts more work on the engine but again, being comfortably cool is the better option.

For the best mileage:

*Keep tires inflated properly

*Change your air filter when your manual recommends to (more often if you drive on a dusty road a lot

*Change your thermostat when your manual recommends to

*Change your oil and filter " " " " "

*Change your spark plugs " " " " "

*** KEEP YOUR MAINTENANCE UP TO DATE

*From a stop, reach the speed limit in around 8-10 seconds because increasing speed uses more fuel than maintaining your speed (don't punch it. Every vehicle is different.)

*Drive at a consistent speed (stay within 2-3 mph of the speed limit)

*Coast down hills

*When coming to a hill, slowly accelerate before reaching the hill and let off when you reach the top of the hill.

*Only fill your fuel to half or 3/4's of a tank. Less weight equals better mileage.

*Make sure your fan/ serpentine belt is tightened to the vehicle specs. If it's too tight your engine has to work harder.

Hope this helps

Open the glove box, push "in" on both sides of glovebow to allow it to fall forward. The filter is behind the glovebox door, squeeze both sides of filter holder inwards, and pull out.

I'm having the same problem, first the air cond. side fan was dragging slow, I tap on it and It would speed up. Now the other one is dragging and the car gets hot just sitting at the red light without the air on. I'm assuming the fan motors are shot and I only have 12k miles on my '04. May try In the next few weeks to remove the fans and have them checked, If that's the problem then I'll opt for after market replacements cause Nissan is sky high.

FIRE WALL SIDE OF ENGINE, A LITTLE UNDER THE EGR VALVE. T HEMPLE

just had this problem with my 97. if your car blows alot of white smoke or has coolant in the oil it would be the head gasket which is usually the culprit to the no heat thing from what I've been told. in my case i got LUCKY. pull the front passenger side up on a curb start the car with the heat on high, take off the reservoir cap and keep filling with engine coolant as needed. rev the engine a little every couple minutes and watch the air bubbles come into the reservoir from the lower hose. now my friend you have "burped" the coolant system. if you still don't have heat or a blown head gasket check the interior floor and see if it is wet. then it would be a heater core.

good luck

If the blower works on high speed, but not on any of the lower speeds, that usually means that the blower motor speed controller is bad. There is a resistor in there which can overheat and burn out. If the blower motor has a bad bearing (makes noise or doesn't turn as fast as it should) that would cause the system to draw more current than normal, and burn out the resistor. If that is the case, you can replace the speed controller, and that would probably fix the problem, but likely it would return in a relativly short time. Without vehicle info, a step by step instruction would be rough... But that is a place to start in you search. Hope this helps.

If you not the original owner! Make sure someone has not ran a direct wire and bypast your thermostat. If they have, take it to a dealer and have it rewired. If it is a direct wire job.. It is a FIRE WAITING TO HAPPEN !!! It is normal for the fan to run continuously when the A/C is on. Turn the A/C off and see if it then runs when you first start the engine. If so, then the thermal switch may be defective.

I would check the coolant level first. When the coolant drops below a certain point,Warm coolant that makes the heater work is no longer present and all you get is cold air. If this doesn't work, I'd try a "hotter" thermostat.

2 different units and different wiring systems.

A mechanic can charge the a/c and then diagnose the a/c unit. Sometimes all it needs is more freon "charging it" or it may have a leak, or a broken part. They can be as much as 1200 to fix. Charging it cost around 75 bucks or you can get a can at auto zone that is fairly easy to use for maybe 10 bucks and try to do it yourself.

look outside where the drain for the ac is and run a coat janger in there to clean it out.

The thermostat may be stuck open.