Highlander A/C

[mcmatt]

Anyone had any problems with A/C or heater? During the first month, we had a heater that was intermittent. It took a damper assy and the A/C pcb replacement to fix it.

Now that it is hot, the A/C works but not adequately on 90deg+ days.

I noticed there are NO bubbles in sight glass and I don't think it is overcharged, I think it is near empty! Also, there is no insulation on the low pressure line to compressor. This is the large line that gets cold and sweats when system is running. Has anyone noticed if there low press line is insulated with the black foam tubing that is common in plumbing and most air conditioners??

Any input would be helpful.

Thanks

[Dianne]

I have yet to hear about any Highlanders with cooling problems... what did your dealer say?

Originally posted by mcmatt
Anyone had any problems with A/C or heater? During the first month, we had a heater that was intermittent. It took a damper assy and the A/C pcb replacement to fix it.

Now that it is hot, the A/C works but not adequately on 90deg+ days.

I noticed there are NO bubbles in sight glass and I don't think it is overcharged, I think it is near empty! Also, there is no insulation on the low pressure line to compressor. This is the large line that gets cold and sweats when system is running. Has anyone noticed if there low press line is insulated with the black foam tubing that is common in plumbing and most air conditioners??

Any input would be helpful.

Thanks

[mcmatt]

The A/C checked out functionally, but it was overcharged with freon. The pressures were a little high and there were never any bubbles in the sight glass. It even looked empty, but after recovering a little freon, the pressures dialed in closer to spec and the bubbles show every once in a while like they should.

Your sight glass should bubble while your are coming up to speed and the system is warming up. Also when you drop or raise rpm suddenly and immediately after you turn off the system until the pressures equalize. This is a very good indication you have the correct amount of freon.

Now it makes dew on the outside of the windows if you leave it running when it is humid outside!! Much better.

I am still going to insulate the low pressure line though. Every other car I have had including 2 Toyotas has been this way and it makes sense. I guess I'll see.

[Kev42]

Thats odd, the AC in my Highlander can turn the thing into a freezer in 100 degree weather. If you crank the temp knob all the way into the blue and kick up the fan, it gets uncomfortably cold.

[mcmatt]

My system wasn't charged exactly correct. I have learned more than I wanted to about it!

An update to my earlier post about sight glass bubbles...it applies to most cars, but not to this one!!

According to factory manuals, the HL has a "sub-cooling" condenser. It is charged to where bubbles disappear and then 100g of refrigerant is added. This brings the charge to a state where it can be sent as almost all liquid through the condenser. Cooling in the liquid state is much more effective for lowering refrigerant temp when the freon expands back into gas.

There is a narrow window between undercharged and overcharged! Thank goodness for warranties.

My vent temps are now 40F with an ambient of over 90F. If anyone has measured vent temps, it would be very useful info.

We have a black HL and I think that doesn't help.

[chawki12]

When I took My Highlander in for its 10,000 mile sevice the dealer said that Toyota recommends changing the Air Conditioner Filter Every 10,000 miles. The price would be around $150.00. I think this is probably a scam. Does anyone really know how often to change the AC filter or maybe a test to determine when it needs to be changed. I was thinking of using a air speed indicator, take a baseline on a new higlander. Take this reading every 10,000 miles and when there has been a 10% drop in air speed change the filter. What do you think.

[Eddie]

In the same-platform Lexus RX300,we recommend replacement every 30,000 miles.
Honestly,it's dependent on where you live and how clean you keep your vehicle. Some cabin filters I've replaced are a little dusty,while some filters were FILTHY...leaves,acorns,nicotine,and dog food (yes dog food). Just inspect it every 15,000 miles or so (should be behind the glovebox).

[Vansolo]

Is it just the RX300 and Highlander that have this Air Conditioner Filter, or other type of cars have it too? How much is it just for the filter at a Toyota dealer? Also, $150 just to replace it. No thank you, I can do that myself.

[edwardh1]

Has anyone measured their Ac outlet temp?
I measured mine- on recirc, 2nd fan speed, on max cold.
on a 90 degree day it puts out like 42 degree air - that seems to be the "cycleout' temp.

My 94 Camry (bests ac ever) did in the 37 38 degree range.
Anyone ever checked theirs/ I used a dial thermometer.?????

[edwardh1]

thanks for the input.
my new silver HL on 90 degree days , fan on 2 (1 slowest, 4 highest) , recirc, say 30-40 mph car speed, puts out 42 degree air. center vent. thats temp where it cycles, you can see the temp then rise 2-3 degrees and it then drives back down to 42.

My 94 camry puts out 37 degree air. my 99 infinity puts out 40 degree air but takes longer to get cold. 94 camry pumps it out cold almost instantly (first 5 min).

no bubbles on the HL. I wonder too if its overcharged. it does "make water" and it does cool the inside windows (sweat a little)

hope Ac is adequate when it gets to 100. (I really think Toyota is getting nearer the edge on cheapening the product over the years.)

black is a pretty car but bad in hot climates - soak temp is real high.

[mcmatt]

Yes, you don't want to see any bubbles on a HL. The charging procedure is to get the A/C to just past the "bubbles in the sight glass" range and then you add a specific amount of refrigerant measured by weight. I believe it was 2 or 4 ozs. I would have to get the book out again. This puts the compressor in the "sub-cool" range. The theory is that if the freon is completely liquid when it enters the condenser it will be more efficient and give off more heat.

I haven't had any problems with my system since getting it charged correctly. I think it was definitely charged incorrectly from the factory or somewhere along the way.

I've learned more about this since way back then, so if anyone has specific problems, I will be glad to add $0.02.

[edwardh1]

i thought the freon left the evaporator as a cold gas, was compressed by the compressor as a gas, and then entered the condenser as a hotter gas, and then left the condenser as a hot liquid. cooling effect being the state change in the condenser, not any cooling of the hot liquid leaving the condenser
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overcharging has been done for years - on GM products in the 60s and 70 and maybe beyond it was common to charge til no bubbles, then add 1/2 can more to allow for system surges (and of course, continual GM system leakage)

[mcmatt]

I am not an AC person and I shouldn't have quoted from memory. Here is a quote from the HL Technical New Car Features. The book says there is a multiflow condenser. The last section of the condenser is referred to as the super cooling portion. Where "both the liquid refrigerant and the gaseous refrigerant that could not be liquefied are cooled again in the super-cooling portion. Thus, the refrigerant is sent to the evaporator in and almost completely liquefied state."

My understanding is that a "not as hot" liquid going through the state change in the evaporator will be cooler than compressed gas going through the evaporator.

Remember, I am only relating a laymans understanding. Thanks for bringing it to my attention.

[LGL002]

Sub cooling in the condensor is when the liquid in the lower portion of the condensor is at a lower temperature than the liquid occuring at the point of condensation. It can add a little boost to the liquid refrigerant as it changes state again from a warm high pressure liquid in in the liquid line through the metering device and then to a lower pressure vapor in the evaporator where the vehicle cooling takes place. The newer refrigerants (freon is or was a DuPont trade name) like todays R-134A are different to a degree than the old R-12 systems in the way they work. The overall internal pressures on R-134A are higher than R-12 and are very very touchy to having the correct charge. Pain in the butt for an old HVAC guy but it was driven by the ozone layer depletion theory. In the 60's when that theory began the refrigerant manufacturers fought it tooth and nail. Then after a few marketing types got to thinking, hey if we have to develop new refrigerants and people have to convert systems we're looking at a bonanza. They jumped on the green theory quadrupled prices for a while and there we are. Sore subject , I'm done now.

Larry

[edwardh1]

it almost sounds like they are just saying they made the condenser a little bigger.
condenser is supposed to change it all to a liquid before it goes to the evaporator. if its not liquid at enetreing the evap it is not good.
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say ---have you ever measured your outlet temps again?.in really hot weather? like 95 with fan on 2 and recirc and 30 MPH?
i used a metal dial thermometer that I checked in a glass of ice water .