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Idle vent temp question for people who live in +90 degrees

5K views 31 replies 8 participants last post by  ANTIQUECASTLE 
#1 ·
I've never had good a/c since I bought the van in 06. I'm on my 3rd compressor, just had the system flushed and replaced the condenser as it was original.

At hot start up on a Florida peak heat 93+ day, 104 heat index, letting it idle for about 15 min with a/c on max I get 60 degree air out of the vents. Internal temp of the van was 120 according to my thermometer. Ambient was 94.

Drive for a while in peak heat and I get down to about 42 degree temps coming out of the vent. Stop at a light and it goes up to 50 out of the vents.

Fan clutch is new, a/c system has been flushed, o-tube and receiver dryer replaced. Pressures at idle at 85 ambient were 42 & 220 which is in spec on r134a charts.

Is this thing just a big box with a tiny A/C system?

For those in hot areas, what are your vent temps?
 
#2 ·
The heat capacity of the A/C system can only drop the internal temp 40*below the a outside ambient temps when driving. When idling your not getting any flow through the condensor so engine temps raise that threshold. Sounds like your system is up to snuff. You need an external pusher fan to help.

If you rarely have passengers plug up the passenger vents. I did and now I often click the A/C off because I'm frozen.

My vent temp is 42* when I'm moving.
 
#3 ·
That is what I thought and thanks for your feedback on this post as well. If you recall from my other post, increasing RPM's at idle didn't bring down the temp. With the new condenser it does.

I have a radiator fan off of a Suzuki Samurai in the garage. I might strap it on to the condenser and hard wire it on. At the very least, I'll try to pull the grill and do the leaf blower test this weekend.
 
#4 ·
Two weeks ago it was 110 degrees daily for a week or more here in Phoenix. Ambient air temp inside the van then becomes about 127. It's hot!

The air in our vans could be 32.01 degrees coming out of the registers but it still wouldn't cool off our big box very quickly. It doesn't blow very hard so the 40-50 degree or so air doesn't "hit us" and cool us. Instead it just sort of cascades into the box.

Pic is infrared thermometer aimed at my seat covers, illuminated by the sun through limo dark tint windows -



Lump
 
#6 ·
Lumpy said:
97cargocrawler said:
If you rarely have passengers plug up the passenger vents. I did and now I often click the A/C off because I'm frozen.
Did I already ask and did you already explain? How'd you block them?

Lump
I put some aluminum tape over the vent. I didnt want it permanent. Kinda looks like crap but so does the entire inside of my van. Be sure to do the floor vents too. Now I have my own personal blizzard machine. Double the airflow at 42* is friggin cold. Of course it has to blast right at you to work.
 
#8 ·
Long story short but I got a great deal on labor from a mechanic I know so I had the system flushed again and replaced compressor the dryer and o-tube, yet again. Another ebay 149.00 with free shipping deal. The prior new compressor was noisy after the condenser change and I didn't want to deal with this all over again.

So at this point I have a new radiator, compressor #4, flushed twice, new compressor, new o-tube, new dryer and new fan clutch. I was getting 52 on hot start/idle and 38 on the highway.

I pulled the grill off and mounted a 12" fan on the condenser at peak heat and tested it by powering it up with a battery charger. It moved a hell of a lot of wind but made no difference in air or coolant temps. In fact the fan was spinning pretty good on it's own with the pull from the mechanical fan and I could see it speed up and slow down which confirms the thermostatic clutch is working.

I was surprised the fan made no difference but since everything is new on the front, I guess it makes sense.

The best part is now with cold air my wife wants to keep the current travel trailer and the Astro for another year! This pushes the Yukon XL and 38' travel trailer back at least another 12 months! Now you see why I went overboard on the A/C repair.
 
#9 ·
I went round and round with mine several years ago trying to get it to cool like new. Turned out my 2000 is a magnet for sucking in debris and clogging up the evaporator-
cloggedevaporator.jpg


I've always meant to put some kind of screen over the fresh air intake behind the passenger door hinges, but haven't yet. I really should, since my evaporator is new.
 
#10 ·
I have pondered if stuff gets sucked up from the floor. My airflow id ok but I would not say great. Since I'm in SWFL, it has always been on max/recycle so I would guess it should be clean but you never know.

What would be the easiest way to get to that side of the evaporator? Pull the blower fan or split the case?
 
#11 ·
Using the HPTuners stuff today I programmed the ecm to raise the idle speed with A/C on and in gear by 50 rpm and A/C on and in P/N by 150.

Does seem to help with a/c performance at long term idle such as when the wife is parked sitting in car line waiting for the kids to be dismissed.
 
#12 ·
Logically, if your A/C is cold while cruising down the highway... then that rules out a bunch of things and narrows it down quite a bit. You've said it gets cold while cruising, so coolant levels must be adequate because it does get cold while driving. The blower and evaporator combo must be fine too... again since no problem while cruising. The only thing left... the biggest difference it would seem, is the amount of air moving through the condenser while idling... again evident by your comment that it's cold while cruising, but warms up when idling.

The stock fan "should" be pulling enough air across the condenser, unless there is some related issue. Is the stock fan actually working properly? You stated it pulls enough air to turn the added electric fan, but is it enough, and working adequately?

Is the shroud in place? The shroud is essential for pulling air across the entire radiator and condenser when idling. As soon as you start moving... more than enough air is forced in over the entire condenser. Well this needs to be true while idling as well.

Is the stock "air-cleaner box" in place? This might seem odd... but it is also an essential part of the shrouded system as well (not sure about all the models). It is designed to cover the gap and form a "seal" between the top of the radiator and the condenser, so that all the air that is pulled thru the radiator is also pulled thru the condenser. If it's not there, there will be a huge gap between the two... allowing some of the air to pull from around the condenser bypassing some of it at idle.

The add-on electric fan on front should have helped... but again, for optimum performance, the air needs to move across the entire condenser, and it must be an adequate amount as well.

How does your vehicle temp look while idling in the heat with the A/C on?

Have you checked your A/C gauges after it warms up and starts to perform poorly? Poor condenser air flow will usually show up as climbing higher head pressures (with slight throttle) as a result of higher condenser temperatures.

Lastly, as other have stated, there will be "some" normal decrease in performance while idling, but should be minimal as well. Blocked condensers, evaps, and other parts not operating up to full potential could "add" to the lack of performance as well.

I say though, if the A/C operates fine while cruising but suffers idling, then the problem is probably not enough air moving across condenser while idling.

Good luck.
 
#13 ·
The extra idle RPM is letting the compressor produce better pressure. Even with correct air through the condenser. It will get warmer if the compressor isn't producing enough liquid to evaporate in the entire evaporator surface. If it is boiling out at half way then it is only half working.
Compressor is a air pump. If it isn't turning it ain't pumping squat. 550 RPM ain't much for it to work with.
 
#14 ·
Thanks for the reply. Yes fan clutch is new, shroud is in place and stock airbox in is place. In really hot traffic situations I can hear the fan clutch engage where I could not hear it before.

I have an old post here about not using the stock airbox and the ecm pulling timing but I digress.

When I say warming up, I mean vent temps climbing to low to mid 50's when at cruise in peak heat it will eventually pull down to 40. Even when I got it, this thing never got ice cold at first start/idle. It has been really hot down here as well, 99 actual, 104 relative. When you get in the van, vent temps are 120. Drive it for 3-5 miles and it pulls to 60.

I'm not sure there is much more I can do and think it is just a case of record heat and a tiny little compressor with 8 little vents. trying to cool down a big box.
 
#15 ·
chevymaher said:
The extra idle RPM is letting the compressor produce better pressure. Even with correct air through the condenser. It will get warmer if the compressor isn't producing enough liquid to evaporate in the entire evaporator surface...
Agreed. It is possible as well that the compressor is not producing enough pressure at idle. The ratio of high/low pressure is also essential for proper cooling. If worn, the compressor may not be working to it's full potential at low rpms.
 
#16 ·
chevymaher, I'm going to test it for a bit but I'm thinking of adding more RPM's at idle. There is plenty of room when in gear before I see the TC start to engage and obviously lots of room at idle.

Don't get me wrong guys, with the new compressor, condenser, 2 flushes, o-tube and dryer it is working better than ever. I was hoping it would make ice now but it may be a case of an undersized system and freaking heat from hell here this year.

Note, low and high side pressures are in spec with the various r134a charts online.
 
#17 ·
Oh snap, I just had a thought. Where is the door that closes off the vent to pull outside air on max?

I can see the door open on the passenger floor but I did get some diesel smell inside today when behind a school bus.
 
#18 ·
Hank said:
I pulled the grill off and mounted a 12" fan on the condenser at peak heat and tested it by powering it up with a battery charger. It moved a hell of a lot of wind but made no difference in air or coolant temps...

I was surprised the fan made no difference but since everything is new on the front, I guess it makes sense....
Maybe a dumb question (and I don't mean to insult), but was the fan "pulling" or "pushing"? Obviously, if it was meant to pull from the back and you reverse mounted it on the front, it would be moving the air the wrong direction?
 
#20 ·
I have found vent positioning is critical to feeling comfortable. Eliminating the hot draft from the back of the van. Make a curtain if cool air.Like you said there a very few tiny vents and alot of van. I point the dash vents up slightly over my head. Cool air falls as it travels. Start on MAX air and once it is reasonable turn it to bi-level. Then it is evenly cooling the cab. Legs and head are cool.
I got 2 Y/O compressor it was new, and electric fan, pulling from inside. Sitting idling at 550 it is decent. At 650 or better is is flat cold. I do have a tach.
Mine was a sweat box when I got it. Stop at a light and it flat got hot coming out the vents. I never even tried a new clutch fan. I went straight for the throat and got a electric. Like lumpy said it is blowing leaves under the van with the engine off and you can feel the hot air on your legs standing at the door.
I am not dissing the stock set up. But dad said this van was like that from the day he got it. Air not working idling, engine hot in traffic. I am very satisfied with the conversion. Cold air and cool engine in 100 plus temps is good with me.
 
#21 ·
Hank said:
Oh snap, I just had a thought. Where is the door that closes off the vent to pull outside air on max?

I can see the door open on the passenger floor but I did get some diesel smell inside today when behind a school bus.
It sucks air in in front of the passenger door, but behind the air box under the hood. Under the fender. I hate the sucking in fumes thing my self. I have considered manually closing that forever.
 
#26 ·
Thinking the mechanic didn't pay attention that I have rear A/C and I'm short on Freon.

Ambient was 76 tonight and I was getting 25/140. The spread is good just low. The chart I have says 35-45/150-170 at 75F

Will pick up a can tomorrow and post back.
 
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