A/C compressor kicks on and off - Toyota Nation Forum : Toyota Car and Truck Forums

trailerCaptain · 08-26-2009, 08:35 AM

My '03's A/C compressor keeps kicking on and off. It works fine at startup then after I rev it up it starts to cycle every 5-10 seconds. I've swapped relays and re-charged the system. I've read in some posts that the cycling is normal but my a/c just doesn't keep up with the desert heat. Does the compressor need replaced? How hard is the swap?

Thanks!

JasonA · 08-26-2009, 09:45 AM

Cycling every 5-10 seconds is normal. Have you had the system pressure tested to figure out if it's charged? It may just be low on refrigerant. Also, use the recirculate option. I use it all the time. It's much easier on the system (because it's cooling air that's already cold).

trailerCaptain · 08-26-2009, 10:14 AM

I checked the PSI and charged the system yesterday. I guess I do just need to keep the re-circ on all the time. Is there any way to increase the performance or is it just a known fact that toyota's a/c sucks?

JasonA · 08-26-2009, 01:30 PM

I'm not sure I'd say it "sucks"...high heat is going to be hard on any A/C system. My Corolla is no better or worse than any other vehicle I've had as far as A/C performance. But I keep the recirc on almost all the time whenever it's moderately warm anyway, just because it's more efficient to do so. With recirc on all the time, you don't lose much with super hot weather.

mikered30 · 08-26-2009, 07:43 PM

I think my AC sucks, takes for ever to cool down, even in PA, but it works. What was the PSI on both sides? I insulated my low line, made a slight difference, but no biggie.

emptystreets130 · 08-26-2009, 08:15 PM

There's no way to increase the performance of the a/c system. Not unless you add another fan to the condenser. But the Corolla A/C system normal takes awhile to cool the whole car down. Especially with a black interior. What what is the PSI on the low side. If it's over 45-50 PSI or below 30 PSI then thats one problem.

JasonA · 08-26-2009, 09:05 PM

Having Desert Sand Mica paint with the tan interior helps I guess. My windows are also slightly tinted. I think they're 50%, but they could be 35%, I'm not sure. It's not limo dark, but definitely noticeable. That probably helps.

gideon1331 · 08-26-2009, 09:51 PM

Actually, it is VERY easy to improve the AC in these cars. Remove the cabin air filter for the summer. AC performance is vastly improved without a filter installed.

The issue isn't with insufficient air passing over the condenser, but with insufficient air being pulled through the system inside the car.

emptystreets130 · 08-26-2009, 10:06 PM

I'm pretty sure removing the cabin filter does nothing in increasing cooling performance. My tC didn't have a cabin filter to begin with. After adding one, vent temp stayed the same. I can see the cabin filter restricting the flow, but it's a very small restriction.

Reason why I say add another fan to the condenser is because that's where the heat exchange occur. The more volume of air that flows through the condenser fins, the more heat it carries away. It's just like the water spray intercooler on the STI.

gideon1331 · 08-27-2009, 11:17 AM

The only time that fan on the condenser does anything is at low speeds or when the vehicle is stopped. When driving even at normal speeds on back roads far more air is being pushed over the radiator/condenser than a fan could ever hope to move.

Air filters are EXTREMELY restrictive, no matter how 'high-flow' they are. With the air blower in these cars, airflow nearly doubles without a filter installed.

emptystreets130 · 08-27-2009, 05:08 PM

Quote:

Originally Posted by gideon1331

The only time that fan on the condenser does anything is at low speeds or when the vehicle is stopped. When driving even at normal speeds on back roads far more air is being pushed over the radiator/condenser than a fan could ever hope to move.

Air filters are EXTREMELY restrictive, no matter how 'high-flow' they are. With the air blower in these cars, airflow nearly doubles without a filter installed.

Again, that's not true. My tc didn't have a filter. I added one and there is NO restriction in the amount of air flow.

gideon1331 · 08-27-2009, 06:57 PM

I'm sorry, but you're full of it. There is no way to introduce any filtering mechanism to any air system without severely restricting airflow.

Go turn your blower on high, and with your hand over a vent, remove the cabin air filter. You WILL notice a large difference in airflow.

Unfortunately with today's cars, that is not normally taken into account when designing the HVAC system. Therefore, when a filter is present the system cannot run efficiently as not enough air can pass through.

The average screen in a house window reduces the amount of air that can possibly pass through by a whopping 10 times, and that is with relatively large holes for the air to pass. Now imagine an air filter with microscopic holes for air. The air must slow down in order to pass through, which reduces throughput of the system. There is no way of getting around that.

emptystreets130 · 08-27-2009, 09:10 PM

You're full of it as well. I've been working on Toyota for 7 yrs. None of them has the air flow restriction that you are talking about. Talk to anyone who has a cabin filter in their car. Whether its from Acura all the way down to Subaru. They will tell you that there is NO NOTICEABLE air flow restriction.

How the heck do you know I'm full of it? You don't. I speak from experience, you don't.

Quote:

Originally Posted by gideon1331

The average screen in a house window reduces the amount of air that can possibly pass through by a whopping 10 times, and that is with relatively large holes for the air to pass. Now imagine an air filter with microscopic holes for air. The air must slow down in order to pass through, which reduces throughput of the system. There is no way of getting around that.

10x. WTF. That's over exaggerating.

JasonA · 08-28-2009, 08:14 AM

The cabin filter makes quite a big difference in air flow in my '07. You can certainly feel the difference, but I keep it in anyway because that filter gets pretty dirty and I'd rather have that dirt on the filter than in my nose. I replace that filter every year.

It's the same thing as your home A/C system. If you take the filter out, that HVAC fan runs FAST. Put the filter back, even those fiberglass filters that aren't very "restrictive", and you can hear the fan slow down.

Emptystreets, just a thought: if you retrofitted a filter into a car, it's possible that it's not getting a good seal, so you may not notice a big difference. I own two vehicles with cabin filters, and the difference in airflow on both vehicles is rather dramatic. You can both hear AND feel the difference.

gideon1331 · 08-28-2009, 11:13 AM

Quote:

Originally Posted by JasonA

The cabin filter makes quite a big difference in air flow in my '07. You can certainly feel the difference, but I keep it in anyway because that filter gets pretty dirty and I'd rather have that dirt on the filter than in my nose. I replace that filter every year.

It's the same thing as your home A/C system. If you take the filter out, that HVAC fan runs FAST. Put the filter back, even those fiberglass filters that aren't very "restrictive", and you can hear the fan slow down.

Emptystreets, just a thought: if you retrofitted a filter into a car, it's possible that it's not getting a good seal, so you may not notice a big difference. I own two vehicles with cabin filters, and the difference in airflow on both vehicles is rather dramatic. You can both hear AND feel the difference.

I figured the car just didn't come with a filter and one was just added in the slot. If it is retrofitted there is a good chance very little air is actually going through the filter.

Emptystreets - ask any firefighter you know and they will confirm the 10x figure for window screens. This is part of their training when using those giant fans to pull air through a building.