How to tell if AC system needs flushed?

[STL_G8GT]

Evening! hoping to get some insight here.

Trying to make sure our daughters 2004 RX330 is ready for a new life in Florida. Originally we had a failing AC expansion valve that was making noise. As the summer got hotter the system failed to hold necessary pressures and the system would fluctuate between warm and cold air. I replaced the expansion valve and it took care of the noise and performance. Unfortunately it introduced a new problem to the system where the system would thunk and screech on first ac clutch engagement of the day.

The mechanic that did the recharge thinks there may be debris in the system that the compressor is trying to move on the first start, but I'm not convinced. The reason I don't think that is the issue is because if you start and let the vehicle idle for a few minutes and then start the AC on the first start of the day, the clutch engages silently. Instead, I think it is a worn AC clutch. What I don't understand though is why this issue only showed up after I swapped the expansion valve and the system was recharged. Also worth noting that there are a bunch of accounts of Toyota's on the internet that have this exact same issue, some of them from brand new. All were in the same range of early 2000 years. Some stated that it was compressor slugging.

The AC clutch is hidden by a frame component and you cannot get feeler gauges behind it because it is recessed to the pulley. The way that you measure engagement travel is with an end gauge, but there is not room to get one without pulling the compressor. Vehicle has 170,000 miles on it so I figured I would replace the compressor and condenser anyway.

The plan was to do that work on Monday, but today our daughter went to start the car with the AC off and she said there was a brief sound of screeching, like nails on a chalkboard, that then went away. Even though the AC clutch wasn't engaged, I can't help but think that it's related to our AC clutch issues. I told her to not drive the car until I swap the compressor & condenser. The sound that she described makes me think of a faulty pulley somewhere in the drive belt system. I think it would be too much of a coincidence for it to be anything other than having to do with the AC compressor.

When I changed the expansion valve, I did change the dryer element as well. I have picture of that that I will attach. It had a bit of a gray color to it but no chunks of metal or anything silly like that. The new condenser of course will include the new dryer, as it is attached.

Here is my question... how do I know if I need to flush the system or not? I do not believe that the AC compressor has failed. In the sight glass I see no metallic bits or gray or questionable material, just a slight off green liquid. Because I've already replaced the expansion valve I would rather not dig back into the dash to pull it again to flush the evaporator. Because I'm replacing the condenser, I believe anything that is settled in that will be pulled out obviously. Of course I can view the quality of the oil that I drain out of the compressor, and however clean it is should give me an idea I guess.

Lastly, the best system capacity for oil that I can find is 4.5 oz (although under the capacity specifications page for the manual that I'm using it lists 4 oz, the instructions for compressor install list a different amount which I show below). I believe it is 1.4 oz in each of the condenser and the evaporator and the remainder goes in the compressor. So for my process I'm going to put 1.4 oz in the new condenser, and then drain out what is in the old compressor and drain and fill the new compressor with that amount. (The 2004 rx330 manual that I have found does not list oil amounts, but the 2003 RX300 manual does. So I am going off of those values for oil. Here is the 2004 rx330 instructions for oil on a compressor install:

Standard:

(Oil capacity inside new compressor and magnetic clutch: 120 + 15 cc (4.0 + 0.5 fl. oz.)) - (Remaining oil amount in the removed compressor and magnetic clutch) = (Oil amount to be removed when replacing)

Am I missing anything?

 

[Nukeman7]

Evening! hoping to get some insight here.

Trying to make sure our daughters 2004 RX330 is ready for a new life in Florida. Originally we had a failing AC expansion valve that was making noise. As the summer got hotter the system failed to hold necessary pressures and the system would fluctuate between warm and cold air. I replaced the expansion valve and it took care of the noise and performance. Unfortunately it introduced a new problem to the system where the system would thunk and screech on first ac clutch engagement of the day.

The mechanic that did the recharge thinks there may be debris in the system that the compressor is trying to move on the first start, but I'm not convinced. The reason I don't think that is the issue is because if you start and let the vehicle idle for a few minutes and then start the AC on the first start of the day, the clutch engages silently. Instead, I think it is a worn AC clutch. What I don't understand though is why this issue only showed up after I swapped the expansion valve and the system was recharged. Also worth noting that there are a bunch of accounts of Toyota's on the internet that have this exact same issue, some of them from brand new. All were in the same range of early 2000 years. Some stated that it was compressor slugging.

The AC clutch is hidden by a frame component and you cannot get feeler gauges behind it because it is recessed to the pulley. The way that you measure engagement travel is with an end gauge, but there is not room to get one without pulling the compressor. Vehicle has 170,000 miles on it so I figured I would replace the compressor and condenser anyway.

The plan was to do that work on Monday, but today our daughter went to start the car with the AC off and she said there was a brief sound of screeching, like nails on a chalkboard, that then went away. Even though the AC clutch wasn't engaged, I can't help but think that it's related to our AC clutch issues. I told her to not drive the car until I swap the compressor & condenser. The sound that she described makes me think of a faulty pulley somewhere in the drive belt system. I think it would be too much of a coincidence for it to be anything other than having to do with the AC compressor.

^^^^That is your issue, not debris in the system! The screeching noise is probably the bearings in the clutch pulley starting to fail. If not, it is a failing bearing in the idler pulley or tensioner pulley for the serpentine belt. It probably only showed up after replacing the TXV and evacuating/recharging the system because you now have higher resistance in the compressor due to increased head pressure.

At this point, you should closely examine the idler and tensioner pulleys to eliminate them as the source of the noise. Then proceed with replacing the compressor clutch assembly.

 

[CarlB]

Flushing is for contamination after compressor failure, since it'll spread bearing debris throughout the system. It's also going to be less ideal than replacing components in those situations, since it will be difficult to remove all the contamination from a condenser and evaporator. Flushing isn't something you'd do after replacing an expansion valve.

After replacing an expansion valve you'd replace the drier, then vacuum the system to evacuate moisture before recharging.

The clutch noise doesn't care about the expansion valve.

 

[clinebarger]

A belt squeals one time & it's done, These manual tension belt Toyota's are picky with belts, I've had decent luck with Continental OE series but a OE Toyota would be the best bet.

 

[shortyb]

So after the TXV, does the system blow cold air now?

 

[vwmaniaman]

Sounds like belt tension to me caused by the alternator trying to replace the power needed to start the motor.

 

[STL_G8GT]

So after the TXV, does the system blow cold air now?

Yes, aside from the first start thunk screech if we don't let it idle down, system is great

 

[STL_G8GT]

^^^^That is your issue, not debris in the system! The screeching noise is probably the bearings in the clutch pulley starting to fail. If not, it is a failing bearing in the idler pulley or tensioner pulley for the serpentine belt. It probably only showed up after replacing the TXV and evacuating/recharging the system because you now have higher resistance in the compressor due to increased head pressure.

At this point, you should closely examine the idler and tensioner pulleys to eliminate them as the source of the noise. Then proceed with replacing the compressor clutch assembly.

I'll check the tensioner / pulley when I pull the belt for the compressor swap. Ty.

Crazy thing is as I search, I don't see the tensioner pulley listed on its own, only the whole tensioner assembly @ 300. That's a real pain.

 

[shortyb]

Yes, aside from the first start thunk screech if we don't let it idle down, system is great

Then it's not the compressor failing unless your pressures are really off. What is your vent temp when system is on? And what are the pressures at ambient? R-134A? I'm still learning my way around automotive A/C, but all things point to, as @Nukeman7 said, there is a failure with the clutch or one of the pulleys due to increased pressure resistance on the compressor drive. In this situation, it doesn't necessitate a compressor replacement or a flush of any kind. Since you replaced the drier, you should be good with no moisture if you pulled the vacuum sufficiently. Did you or a shop evacuate/recharge the system? If a shop did the evac, did they pull out any of the PAG oil along with the refrigerant?

 

[STL_G8GT]

Then it's not the compressor failing unless your pressures are really off. What is your vent temp when system is on? And what are the pressures at ambient? R-134A? I'm still learning my way around automotive A/C, but all things point to, as @Nukeman7 said, there is a failure with the clutch or one of the pulleys due to increased pressure resistance on the compressor drive. In this situation, it doesn't necessitate a compressor replacement or a flush of any kind. Since you replaced the drier, you should be good with no moisture if you pulled the vacuum sufficiently. Did you or a shop evacuate/recharge the system? If a shop did the evac, did they pull out any of the PAG oil along with the refrigerant?

Hey shorty, thank you - I relied on a shop to do the evacuation and recharge. I don't believe that they pulled any oil out, and I believe that if they did they would have refilled what they pulled. The condenser as it is is pretty beat up, if you look at the RX330 design the lower half of the condenser is exposed to road rocks, so it's time to go anyway. I can't replace the AC compressor pulley on the vehicle because of access, so I have to remove it anyway. With 170,000 miles on the car, I just figured I would replace the compressor as well instead of searching for a clutch/pulley replacement.

Edit - you did answer my question though I don't need to flush the system. I should be good to go with whatever oil comes out of the compressor being one for one replaced plus put 1.4 oz in the new condenser per the service manual.

 

[clinebarger]

I'll check the tensioner / pulley when I pull the belt for the compressor swap. Ty.

Crazy thing is as I search, I don't see the tensioner pulley listed on its own, only the whole tensioner assembly @ 300. That's a real pain.

It doesn't have a Tensioner, The belts are manually tensioned....Meaning they need periodic adjustment which is rarely done, By the time the belt makes noise it's to late & the belt is smoked.

 

[STL_G8GT]

It doesn't have a Tensioner, The belts are manually tensioned....Meaning they need periodic adjustment which is rarely done, By the time the belt makes noise it's to late & the belt is smoked.

So I vaguely remember the last time that I was in it that the power steering belt is adjusted by creating tension with the power steering pulley itself and there is a locking bolt. There's something similar with the alternator. But when I search on RockAuto there sure is a pulley tensioner available. I wonder if it's a retrofit part. I'll have to dig into that. The belt tension would have been adjusted when I did the timing on it 5K ago.

 

[shortyb]

Hey shorty, thank you - I relied on a shop to do the evacuation and recharge. I don't believe that they pulled any oil out, and I believe that if they did they would have refilled what they pulled. The condenser as it is is pretty beat up, if you look at the RX330 design the lower half of the condenser is exposed to road rocks, so it's time to go anyway. I can't replace the AC compressor pulley on the vehicle because of access, so I have to remove it anyway. With 170,000 miles on the car, I just figured I would replace the compressor as well instead of searching for a clutch/pulley replacement.

Edit - you did answer my question though I don't need to flush the system. I should be good to go with whatever oil comes out of the compressor being one for one replaced plus put 1.4 oz in the new condenser per the service manual.

Well, that makes sense that you want to replace it. One less variable to go bad once the car is out of your hands. And if you're already doing that, may as well do the compressor too. At least that should solve any clutch issue. You already have a new expansion valve, so that would be all of the components I would replace to keep from having to go back inside the system again. Only other component I would get is a new pressure switch. These things are relatively cheap, but will cause the system to not activate if they go bad (which they do). Then you have to evacuate/recharge all over again for a $40 part.

The majority of the PAG oil in the system will be in the compressor and condenser, not much remains in the lines, so add oil accordingly. I would consider draining the shipping oil out of the compressor and replacing with new PAG oil, however, I wouldn't put the full system capacity back into just the compressor, probably just 3oz. Make sure to spin the compressor manually to distribute the oil so it won't hydrolock the compressor. The remaining 1.0-1.5oz. of oil can go into the condenser input side and will help it get distributed when the system starts running.

 

[Capt W]

You're pretty spot-on with your past and future oil analysis. Serious internal failure (versus normal wear) would be obvious in the oil, which would turn silvery-gray. Did you notice any off-colored oil when you pulled the expansion valve?

It would be helpful to know the pressures before & after your repair so far. If your ambient temperature is, for example, about 80 degrees, you should be seeing steady low side pressure around 40 psi and high side pressure in the 200 neighborhood.

That grunchy noise on first startup of the day is not unique to Toyota, per se, but can effect anything with these Nippondenso compressors. You should have the very common 10S17C compressor, variations of which are everywhere. My 2008 Charger R/T and 2007 Caravan have the exact same units. The Charger sits a lot and only gets driven about once a week. Every single time we select the A/C we get that noise on the first start. Every other start is a quiet "click." If you live in a very humid area (as I do), it's not uncommon for the clutch and compressor faces to develop a bit of flash rust after sitting a while (just like brake rotors). The noise is due to the buildup on the clutch and generally cleans itself after a few cycles, which is why the noise goes away. FWIW, I bought that Charger brand new and the A/C system has never been touched in over 18 years.

My van is driven almost daily, so the noise is less common. If I let it sit a while, however, it will do the same as the Charger. That system has also never been opened since new and is cold as all get-out.

Let's get back to those pressures. A few weeks ago the system in my '86 Daytona suddenly went warm. Not good on a 95-degree South Texas day. This is an R134a conversion I did back in 2012. Absolutely no leaks and the compressor cycled as normal. The issue screamed expansion valve, but when I hooked up the gauges I saw a steady 40 psi on the low side, but the high side struggled to hit 100. And while the expansion valve could have been the culprit, it was a distinct possibility the compressor was weak and/or failing.

I had two reman compressors in stock (Rock Auto Four Seasons closeouts), so decided to swap the compressor, expansion valve, and drier. Upon reassembly and recharging I was again seeing 40 psi on the low side, but close to 300 psi on the high side (normal for a 100-degree day). Outlet temps are in the low-40s while idling and hit 38 on a test drive. Job done.

Pressures are important indicators of what's going on. The noise may or may not be normal...especially if the car sits in a humid area.

If you end up replacing that compressor, do yourself a favor and steer clear of the Amazon Chinesium, which is everywhere. Spend the extra few bucks on a Denso replacement. And for the PAG-46, get the 8 oz. bottle with the added green dye.

 

[STL_G8GT]

You're pretty spot-on with your past and future oil analysis. Serious internal failure (versus normal wear) would be obvious in the oil, which would turn silvery-gray. Did you notice any off-colored oil when you pulled the expansion valve?

It would be helpful to know the pressures before & after your repair so far. If your ambient temperature is, for example, about 80 degrees, you should be seeing steady low side pressure around 40 psi and high side pressure in the 200 neighborhood.

That grunchy noise on first startup of the day is not unique to Toyota, per se, but can effect anything with these Nippondenso compressors. You should have the very common 10S17C compressor, variations of which are everywhere. My 2008 Charger R/T and 2007 Caravan have the exact same units. The Charger sits a lot and only gets driven about once a week. Every single time we select the A/C we get that noise on the first start. Every other start is a quiet "click." If you live in a very humid area (as I do), it's not uncommon for the clutch and compressor faces to develop a bit of flash rust after sitting a while (just like brake rotors). The noise is due to the buildup on the clutch and generally cleans itself after a few cycles, which is why the noise goes away. FWIW, I bought that Charger brand new and the A/C system has never been touched in over 18 years.

My van is driven almost daily, so the noise is less common. If I let it sit a while, however, it will do the same as the Charger. That system has also never been opened since new and is cold as all get-out.

Let's get back to those pressures. A few weeks ago the system in my '86 Daytona suddenly went warm. Not good on a 95-degree South Texas day. This is an R134a conversion I did back in 2012. Absolutely no leaks and the compressor cycled as normal. The issue screamed expansion valve, but when I hooked up the gauges I saw a steady 40 psi on the low side, but the high side struggled to hit 100. And while the expansion valve could have been the culprit, it was a distinct possibility the compressor was weak and/or failing.

I had two reman compressors in stock (Rock Auto Four Seasons closeouts), so decided to swap the compressor, expansion valve, and drier. Upon reassembly and recharging I was again seeing 40 psi on the low side, but close to 300 psi on the high side (normal for a 100-degree day). Outlet temps are in the low-40s while idling and hit 38 on a test drive. Job done.

Pressures are important indicators of what's going on. The noise may or may not be normal...especially if the car sits in a humid area.

If you end up replacing that compressor, do yourself a favor and steer clear of the Amazon Chinesium, which is everywhere. Spend the extra few bucks on a Denso replacement. And for the PAG-46, get the 8 oz. bottle with the added green dye.

I appreciate all this. I got a bottle of PAG 46 from napa. I don't think that there is dye in it... I'll check!

 

[Capt W]

I appreciate all this. I got a bottle of PAG 46 from napa. I don't think that there is dye in it... I'll check!

You can get a real small bottle of the neon yellow dye from most auto parts for a few bucks. Just drop some into the oil. It can be a huge help if you develop any leaks down the road!