AC blows cold when moving, but warms up when stopped?

[jchristian79]

Is this normal? 2005 Explorer, manual AC controls. Replaced blend door actuator 9 months ago, just pulled out the broken recirc door last week which had stopped the airflow. I sealed up almost all of the fresh intake vent from under the hood cowling too.

This issue has been happening since it's been warm enough to notice the need for AC. When the AC is on (both Max AC and normal) it gets nice and ice cold while moving, even at side street speeds it's fine. The moment I stop at a light or something, I notice it starts to get warmer. Then once I start moving, it cools off again.

I have already checked the refrigerant pressure and it tested ok at about 50 psi (it was about 95 out when I checked and that was the normal range for that outside temp).

The temps in Sacramento have been around 100-105 this week so I've noticed the temp difference between stop & motion a bit more this week. I've never had a vehicle do this before so I'm just curious if this is normal or if there's something going on I could check out? Thanks for any thoughts!

 

[doug625]

a/c is not my area really but I would try sitting still in park and hold the engine rpm's up to around 2000 for maybe 30 seconds and see if the air cools then, if you haven't tried that already...then you'll at least know if it's related to vehicle speed or engine speed. Not sure if being low on freon could cause this or not. The engine turning the compressor faster could compensate for this.. again not sure but I would try this to narrow some things down. Someone else can prolly help more with more A/C knowledge.

 

[rickybobby]

you need to know the high pressure too, the low side can be fine when the high side is too low and the system wont work right.

 

[jchristian79]

a/c is not my area really but I would try sitting still in park and hold the engine rpm's up to around 2000 for maybe 30 seconds and see if the air cools then, if you haven't tried that already...then you'll at least know if it's related to vehicle speed or engine speed. Not sure if being low on freon could cause this or not. The engine turning the compressor faster could compensate for this.. again not sure but I would try this to narrow some things down. Someone else can prolly help more with more A/C knowledge.

Hmm, good idea, I'll try that today.

you need to know the high pressure too, the low side can be fine when the high side is too low and the system wont work right.

Does that mean I need a larger pressure gauge to fit the high pressure side? Or is there another way to check it?

 

[matt0248]

you need pressure gauges on the high and low side to know what is going on. most likely just a bit low on freon and the higher rpms and higher compressor cycling speed are able to compensate. Also air flow does play an important role, if the fan clutch is not operating properly or the air flow through the condenser and radiator is restricted with debris than the system will not work properly.

 

[jghake]

I've noticed that mine is doing the same thing. Keep us updated as to what you find fixes it. I'm leaning towards mine being low on fluid.

Is it best to have a shop do it or is there some way I can fill it myself?

 

[matt0248]

I've noticed that mine is doing the same thing. Keep us updated as to what you find fixes it. I'm leaning towards mine being low on fluid.

Is it best to have a shop do it or is there some way I can fill it myself?

ideally you should have it evacuated and recharged with the exact proper amount of Freon. However, you can buy refill cans at parts stores that come with everything to just add some freon to your system.

 

[jghake]

Do the cans work as well as having the system refilled? I just know the last time I looked into it (a few years ago for a different car) it was pretty spendy to have done. I elected not to....

 

[rickybobby]

Hmm, good idea, I'll try that today.



Does that mean I need a larger pressure gauge to fit the high pressure side? Or is there another way to check it?

you need what is referred to as a "manifold set" it has 3 hoses, one for the low pressure port, one for the high pressure port, and a 3rd for the refridgerent can. You dont have to connect the 3rd hose to a refridgerant can to use it though, as there are valves for each hose. You can get this setup at harbor freight for right around $40 IIRC

 

[Alan Morrison]

Is this normal? 2005 Explorer, manual AC controls. Replaced blend door actuator 9 months ago, just pulled out the broken recirc door last week which had stopped the airflow. I sealed up almost all of the fresh intake vent from under the hood cowling too.

This issue has been happening since it's been warm enough to notice the need for AC. When the AC is on (both Max AC and normal) it gets nice and ice cold while moving, even at side street speeds it's fine. The moment I stop at a light or something, I notice it starts to get warmer. Then once I start moving, it cools off again.

I have already checked the refrigerant pressure and it tested ok at about 50 psi (it was about 95 out when I checked and that was the normal range for that outside temp).

The temps in Sacramento have been around 100-105 this week so I've noticed the temp difference between stop & motion a bit more this week. I've never had a vehicle do this before so I'm just curious if this is normal or if there's something going on I could check out? Thanks for any thoughts!

In really warm weather, you should always use the recirc mode especially when stopped and idling. Another trick is to shift to neutral rather than leaving the trans in Drive. Using recirc mode greatly reduces load on the AC because hot outside air is not introduced to the vehicle. Shifting to neutral eliminates the heat generated by the trans clutch being partially engaged while waiting for the light to change. This heat goes into the trans fluid and must be dissipated by the trans cooler in the radiator increasing the heat load on the radiator. Neutral also reduces engine heat generated by maintaining idle speed with the trans load applied. If none of the above helps, check the fan clutch. If that's OK, have the radiator boiled out.

 

[tower]

I would guess low charge or you fan clutch. I would have the fan checked because if it is starting to go this would be one of the first symptoms as it gets weaker very bad things will start to happen.

 

[blueoval9erlifer]

from what you say you might start by taking a garden hose and washing the condenser and radiator out really good, my buddy who does nothing but ac work in the summer says 90% of the people who come in because their ac is not working good could have saved 40 minutes of his labor by doing this will probably also see your temp gauge drop a little if its clogged.

the other part of this equation is that it is hard for the condenser to cool the refrig back down when it is this hot out. Almost every vehicle out there will have the ac warm up when at a stop if its getting up close to the 100 degree mark. last if there is still freon in the system then there is no reason to have it reclaimed sucked down and then put back in. whats the difference between adding new freon to your system or having a shop reclaim your freon and then put it back into the system. if you get the specs the guages should tell you the story.. if the high pressure is skyrockting then clean the condenser if low side is not right then put in or take out some freon. also if the high and low side do not equalize (shut the vehicle off with ac on) then probably have a clogged orifice.