Sienna a/c vent temps- recharge?

[TmanP]

I posted a couple of weeks ago about a 2010 Sienna with seemingly poor a/c. Today's pretty warm, about 90-ish. I took it for a drive with a meat thermometer in the center vent, and here's what I found:

Recirculate on, max a/c, fan on high: 55 degrees

Recirculate on, max a/c, fan on medium-low: 45-46 degrees

Recirculate off, no max a/c, fan on medium-high: (WHAT I'D CONSIDER NORMAL SETTING): 55 degrees

Recirculate off, no max a/c, fan on high: 60 degrees

Clearly, this isn't enough to keep the van comfortable. I tested my Buick (2006, 150k miles, I think original R134) for a cross reference:

Recirculate off, fan low, temperature set to low: 38.5-39 degrees

Recirculate off, fan medium, temperature set to low: 42 degrees

Recirculate off, fan high, temperature set to low: 43.5-46 degrees

The Buick was plenty comfortable, and I had to turn it up a bit as I was getting too cold. The Sienna's vent outlet temperature was about 10 degrees warmer in similar situations, and it's unpleasantly warm. I think I'll take it to a shop, I called and got two non-commmital estimates (about $200, more if they find a leak). But these temps don't seem normal, do they? The consensus (kind of) was to take it to a professional instead of using a can of R134. Do my temps confirm this?

 

[Nick1994]

If it was nice and cold last year but warmer now, you likely have a leak. A mechanic should check for leaks, it might just be a service port.

Have you checked if the radiator fans are working? No plastic bag sucked in front of the condenser?

 

[mclasser]

I'm no A/C expert, but on a hot day with decent humidity, 55 from the vents doesn't sound too bad. You might just be a few oz low on refrigerant.

 

[bioburner]

I would bet that it needs a bump. I got tired of poor performance last year on the Xterra and had shop pull the system down and I got a new condenser and all is well again. Aluminum and reaction with salt etc., high speed June bugs can close up all the fins. Which reminds me I need to get some door screen in the front of the radiator when I get the X back on the road. Just found after inspection of things after oil change that the rubber boots for and aft of the resonator are cracked.$$

 

[mclasser]

OK, I was curious and just tested my 2 cars on the driveway. 90 deg out, 50% humidity, low fan, fresh air setting, engines revved to 2500 RPM:

Pilot: 45 deg center vent closest to evaporator
I35: 42 deg center vent closest to evaporator

 

[gabriel9766]

I keep a temp guage in my vents yr round. The malibu does about 50°F on eco ac at idle. And 40-43°F at 2k rpm's doing 70 down the highway. This is with it being above 90°F with high humidity. Haven't checked the taurus yet but w/ the rattling ac clutch it will freeze me out.

 

[WillsYoda]

55f is high. Mine is in the low 40s on the highway.

 

[E150GT]

Originally Posted By: bioburner
I would bet that it needs a bump. I got tired of poor performance last year on the Xterra and had shop pull the system down and I got a new condenser and all is well again. Aluminum and reaction with salt etc., high speed June bugs can close up all the fins. Which reminds me I need to get some door screen in the front of the radiator when I get the X back on the road. Just found after inspection of things after oil change that the rubber boots for and aft of the resonator are cracked.$$

Thats exactly what I need on the truck. A new condenser. My ac will freeze you on the highway in the summer and anytime when the sun isn't blazing, but sitting in traffic, it can't hang on a hot day. I remember years ago it didn't matter what the conditions were, you were frozen in the truck. I figure the condenser has lost its efficiency after all these years.

 

[E150GT]

Originally Posted By: gabriel9766
I keep a temp guage in my vents yr round. The malibu does about 50°F on eco ac at idle. And 40-43°F at 2k rpm's doing 70 down the highway. This is with it being above 90°F with high humidity. Haven't checked the taurus yet but w/ the rattling ac clutch it will freeze me out.

I keep thermometers in my vehicles year round too. I get weird looks from people for it. I don't care. My Mazda keeps a solid 38-40 all the time and the truck hovers around 55-60 when sitting in traffic when its hot and 40 when I'm on the highway.

 

[boulderdentist]

I have an '89 Ranger with an intact R-12 system which blows 19 degrees at center vent. It is so superior in cooling compared to the newer R134a. My 2000 Ford Taurus is lucky to get down to 40 degrees. It sounds to me as if you are a little low on charge. The proper procedure is to evacuate, pull a vacuum, wait an hour to see if it holds or loses vacuum indicating a leak, fix the leak, or if no leak recharge to the proper weight of refrigerant. Careful if just adding refrigerant as an overcharged condition can also impede cooling. I am no expert but have read that the compressor shaft has a seal that intentionally leaks small amounts of refrigerant to keep it lubricated. So if you need to add a little every year or two, probably normal, if one season to the next probably a leak that needs repair. Have also read to avoid using refrigerant that has a leak seal added, it will probably gum up the works. I would be tempted to add a small amount of R134-a and track how long it cools OK. If it quits cooling and you want to keep the vehicle would seek professional help. Usually if really low on charge the compressor will cycle on and off rapidly. I had my 2000 Taurus into an AC shop and they evacuated, checked for leaks, then recharged, for nominal cooling, 40-41 degrees. The next summer I discovered the evaporator fan was inoperative. I replaced the fan and it was better. Check as others have said, both fans, evaporator, and cabin air filter. Good luck.

Scott

 

[Yah-Tah-Hey]

I have an '89 Ranger with an intact R-12 system which blows 19 degrees at center vent. It is so superior in cooling compared to the newer R134a. My 2000 Ford Taurus is lucky to get down to 40 degrees. It sounds to me as if you are a little low on charge. The proper procedure is to evacuate, pull a vacuum, wait an hour to see if it holds or loses vacuum indicating a leak, fix the leak, or if no leak recharge to the proper weight of refrigerant. Careful if just adding refrigerant as an overcharged condition can also impede cooling. I am no expert but have read that the compressor shaft has a seal that intentionally leaks small amounts of refrigerant to keep it lubricated. So if you need to add a little every year or two, probably normal, if one season to the next probably a leak that needs repair. Have also read to avoid using refrigerant that has a leak seal added, it will probably gum up the works. I would be tempted to add a small amount of R134-a and track how long it cools OK. If it quits cooling and you want to keep the vehicle would seek professional help. Usually if really low on charge the compressor will cycle on and off rapidly. I had my 2000 Taurus into an AC shop and they evacuated, checked for leaks, then recharged, for nominal cooling, 40-41 degrees. The next summer I discovered the evaporator fan was inoperative. I replaced the fan and it was better. Check as others have said, both fans, evaporator, and cabin air filter. Good luck.

 

[Yah-Tah-Hey]

"19 degrees at center vent?" No matter how the refrigerant is being metered into the evaporator, the evaporator discharge temp will be 34+ degrees or it will soon be a solid chunk of ice. 40 degree at the registers with ambient in the eighties is normal. On a hot,humid day 55 degrees wouldn't be bad either.

 

[boulderdentist]

Perhaps my thermometer is defective? Subjectively it is much colder. I am originally from Lincoln, Nebraska, familiar with the humidity competing with the temperature. That makes the heat index much worse. Now at a mile high elevation and often humidity lower than 10%. I am getting ready to scrap the Ranger, 336,000 miles but I suppose I could take a picture of the thermometer in the center vent. The same thermometer registers about 42 degrees in the 2000 Taurus. I understand what you are saying, but it is consistently 19-20 degrees in the Ranger. I also have a 2010 Subaru Outback with temperatures at 38 degrees, far better than the 40 to 55 degrees you suggest. Maybe it is just the difference in climate or just luck. Thanks for your thoughts.

Respectfully,

Scott

 

[wag123]

TmanP, IMO you are a couple of ounces low on R134A, JUST a couple of ounces, don't overdo it.

 

[Yah-Tah-Hey]

I'm in no way questioning your veracity, but 19F air coming off of an evaporator in a vehicle would be extraordinary. I suppose a system low on refrigerant could produce 19F air but certainly not for very long, even in Boulder. I lived in Craig for several decades and never saw a discharge temp out of any register below about 34F.Maybe some of the AC mechanics will explain this low evaporator discharge temperature. Regards, no offense intended sir.

 

[Rtstrider]

I recharged ours last year as it was a little low. 2011 Sienna here. It made a HUGE difference! We were on the interstate in 100+ degree weather and the ac just wasn't keeping up. It's held ac over a year strong now.

 

[E150GT]

I once thought I was getting 15 ,degrees out of my thermometer. Turns out it was not calibrated.
R134 works [censored] in most systems designed for R12 but an r134 system with r134 works just as well as an r12 system with R12