AC Can't Keep Up On Hot Days

I can't remember the cost but last time I bought one I bought the charcoal filter one and that has lasted alot longer than the white paper one. Its made of better paper. Cost alot more. I check my filter about once a month if I remember. Its so easy and quick. All I do is knock the debris or dust out of it and if at work blow it out with our compressed air.
And the fan coming on is not good. That means the Hybrid battery for whatever reason is getting hot. That not good as heating of the battery module deforms the module case and will eventually prematurely fail.

When the fan gos on look at the MFD Consumption screen and see what the SOC is. State Of Charge of the Hybrid. Try to get handle on why the fans coming on and fix that if its cabin temp or whatever.
If you look at the Hybrid fan with a flashlight you'll be able to see if the inlet is dirty or clogged. The fan inlet must be clear. if clogged that may cause the hybrid battery to overheat too.
Go to lusciousgarage.com and read there service blogs. Lots of good real world info over at Carolyns shop.

 

Where is the 65 F measured? I thought the temperature at the output vent should be somewhere around 40 F?

 

I measured my 07 with 50K miles this morning. Car in garage all night didn't take it out for this test. Garage temp was 84. Inside of car much cooler maybe 78.

Thermo stuck in vent run at max for 5 mins measures 48 F.

 

Inside the middle left vent where the A/C comes out. I measured it the vent just inside and then measured it a little further in, and the readings are about the same. I get 66 degrees after two minutes and 63 degrees after 5 minutes. After 15 minutes, it gets to be around 55 degrees (the lowest it reads to my knowledge). This is all vents open. HI fan speed. LO temp speed. 99 degrees or so outside. There is a picture of the vent I am talking about also. All of the vents fully opened. It actually has the lowest readings too.

A/C compressor on and recirculating inside air.

I don't know....is it supposed to be around 40 F? In that case, my A/C might have an issue. The lowest I have seen was 55 F, although I assumed this was good since it it much cooler than outside, although I do not know. It takes a long time to cool off.

 

Ok thats not to bad but my ac is much cooler. Since you are cooling pretty good but not excellent if it was me I would look at the condition of the AC condenser on the front of the car. Its the thin one in front of the rad. See if its clogged. Take that big black plastic valence plate off that goes over the top front of the engine compartment. Phillips screwdriver. Snake your hand behind the screws and push them out while you unscrew them with the Phillips. They come right out.Super easy 6 screws.

Then make sure the condenser is not bug clogged. Should be clean shiny aluminum. If dirty or clogged go to Home Depot and buy the blue pressurized can of AC COIL CLEANER. Wet down the front of the car paint bumper etc with the hose first so if any cleaner gets on paint it won't remove wax. Then Hose the front of the condenser down with the cleaner and let sit.
If really bad may need a brush. But try cleaner first. Then rinse off fins good with garden hose. When dry inspect closely for an damage from road rock. Look for dents especially on the bottom. Check condition of the bottom plastic cover plate. That plate must be on or condenser gets a beating form road fod.
I do this every year without fail. Thats why my AC is so cold.
When complete do another thermo test. I bet it will be cooler.

BTW, want to make your house ac 5 degree's cooler instantly? Do the same thing to your home outside unit. You will not believe how much dirt clogged that outside unit gets. Save you alot of $$$$ both the car & home doing this simple thing.
Turn both inside & outside breakers off. Unscrew top cover plate. Hose with cleaner on outside of coil and then rinse under pressure. Rinse from inside out as the fan pulls air from outside in. What a difference that makes.

Of course the inside unit needs a microbial cleaning too now & then and both probably due for motor start up cap replacement to but that's another post. Good luck.

 

Probably so. I am going to look into that. As Ed recommended, I might have to check the condenser. I basically took it into Toyota and they said it was fine without even checking it. I do have a warranty on the car. They told me it was completely normal to take a long time (at least 15 to 20 minutes) to cool off, which is completely understandable, although I thought it was strange that they did not even check that. I suppose it is just because it works harder in the heat, although I will have to check the condenser.

I should have noted though...my car has seemed to have another issue, although it appears to be nothing with the A/C. My engine "bucks" or "jolts" when going into park. Sometimes the ICE also runs rough. I have not been able to figure out what is going on although I realize this should be a separate issue than the A/C unit.

 

I would like to reiterate that if your air conditioning system cannot make you uncomfortably cold in the summer, then something is wrong with it. I took these photos a couple of years ago. Note that ambient temp is 95 degrees F while the air output from the center vent is near freezing temp.

 

Yes mine was sitting in the garage so I gave you worst case temps. When your rolling and air is flowing through the front
condenser it should be much cooler than 48. I can say even when my car is very hot on Auto it will cool the car down in less than 2 minutes. Very good ac in our cars.
If not cold enough only thing you can check at home is a clogged condenser or ac assist fan behind rad is not coming on.
If those ok and still not good ac it needs to be checked by a professional sonmeone familiar with a Prius by hooking gauges to it to check level of freon in the system.

 

Good point, Patrick. I took the car to my mechanic to check the A/C. While Toyota told me it was "normal" to take a long time 15-20 minutes to finally start feeling cool, my mechanic found that it only had 6/10 of a gallon of freon. He added in freon and added some dye, because the leak should eventually show up. (I think the idea is that if the system needs recharging then there is a leak.) Also, he cleaned off the condenser, yet there might be some rocks that may have made their way in there too. The A/C definitely is cooling faster now.

Thanks Patrick for the information! Glad I went to my mechanic who actually checked the A/C. I was surprised that Toyota did not even look at the A/C. Why do you think Toyota didn't want to check the A/C? It was strange that they didn't even offer to look at it (had an adviser appointment also). The hybrid technician was the one who told me it was fine.

I also realize this dealership is the same one who overfilled my oil. I noticed the oil a little overflowed the other day. The mechanic was shocked that my oil was overfilled and asked if I took it back, although I only barely noticed. Not too happy with that dealership! They are supposed to do everything well since they are Toyota!

 

If you can park your prius under some shade, I find this trick also helps the AC keep pumping out cool air. House garage, parking garage, carport, shady part of a building, tree, or a portable 10 x 10 canopy will do.

DBCassidy

 

Patrick knows a lot more about Prius than I do, however I want to share this info with you. I live in Houston, and recently I have noticed that it takes a long time to cool off our Prius too. After doing some searching here on Prius Chat I found that the Gen 2 Prius has a sight glass on the A/C system. According to post's I have read, the way to check the glass is to look for bubbles when the temp is set to LO and the fan is on the highest speed (NOT AUTO). If you see bubbles, then you are low on freon. At that point, have your system checked with gages and find the leak. Our Prius was doing the same thing you describe. I checked the glass, saw the bubbles. Went to the stealer, they checked the system and found the condensor was leaking. Probable cause is damage from stones being thrown up from the road. Cost to repair, approximately $800 for the job at the stealer. You might be able to get a local mechanic to do the job cheaper if you feel confident in their service. The condenser new is just over $300 from Toyota which includes a new dryer. The rest of the job is simple labor, plus some freon and vacuuming out the system before recharging it.

I note that when the system is properly charged, the Prius will blow 45 degree air when measured at the left center vent after the system has been running for about five minutes. That is with the temp set to Lo. Fan speed does not seems to cause the temp to change much. However, if the charge (Freon) is not full, the temp coming out of the vent will be much higher and will take a long time to cool the car down. At the time I took those measurments, the ambient outside air temp was 91 F according the MFD.

Long story short, check the sight glass, and have someone put a set of gages on your Prius. If the pressure is not right, find the problem and fix it. Then you should have COLD air again.

Ron (dorunron)

 

Thank you. This is interesting that you say that, because sometimes my car will randomly start blowing at a higher fan speed after it is already on high, which I find strange. If I have the dealer look at it, how much do you think they will charge? I have a warranty on the car, so I figure this would be a good thing to do if there is an issue with the condenser. My mechanic did add dye, so hopefully that will help pinpoint where the leak is.

I might go to another dealership because the dealership I went to before just didn't have the right answers. They told me something about the A/C does not work well unless you have tinting, which is plain wrong. Yes, more heat enters cars that don't have tinting, yet the power output should be pretty good for any Prius.

How easily do you think a dealership can find a leak? Are they really the experts on the Prius (I know they are supposed to be)? Do you know how long it takes to pinpoint a leak after they added dye, or do you think the gages will be able to pinpoint the leak at the Dealership?

 

You asked how easily someone will find a leak. That is really not easy to answer. There are a multitude of places where leaks can occur. Most are found visually, however sometimes if the leak is small it requires a sniffer to find it. Generally, where ever there is a leak, you will find a lot of moisture (oil from the freon, not water moisture), as well as grime, filth etc. Anywhere where there is a connection in the system is subject to leaks, as well as the individual components themselves. Sometimes, it can be easy and quick. Other times it might take a while to nail it down.

The gages are used to check pressure. If a system is low or over filled, the pressures will not be correct.

Have you checked the sight glass yet? If not, try to find it under the hood of your car. It should be on the passenger side of the vehicle towards the front. I am posting a pic of it so you can see what to look for.



More information on the sight glass:A/C - bubble in sight glass | PriusChat

Ron (dorunron)

 

Yes, this is completely normal!! Toyota has the best air conditioner, the heat raise inside the car is so intense the air conditioner has the work through the heat and make the AC cold enough to over-ride the heat. Tint will help alot! It'll be up to 30 degrees colder depending on how dark your tint is