2004 rx330 AC grind on first start

[STL_G8GT]

Apologies as Ive posted this a couple times on different forums, but hoping to get some informed opinions ...

2004 rx330. 175k miles 3.3 3mzfe with AWD.

For a long time we heard a whoop sound in the dash occasionally - pointed me to the expansion valve. Had a trusted local shop verify the issue. I've replaced the expansion valve and drier / filter element in the condenser.

They recharged the system for me after I did that work. With diag, evac and recharge, the cost was ~$400 plus my parts and labor for the mechanical work.

The woop sound is gone but now I have a different sound and it just started after I did some suspension work and had the front of the vehicle up about 8 in higher than the rear. (Sound started about a week ago, the expansion valve work was done three to four weeks ago, but the car is not driven regularly... So we're talking about maybe eight vehicle trips in that time.)

If the vehicle has set overnight or for a long time (seems like a minimum of 6 hours), the AC compressor will make a grinding/clunk noise when it is engaged the first time on the cold startup.

Once the engine is running and ac system is cycling after the first engagement, the compressor will engage and disengage nearly silently. What I am trying now is seeing if turning the AC off before I turn the vehicle off and then waiting a little bit before I turn the AC on when restarting the next day makes a difference at all.

I'm willing to throw a compressor at it, but the bigger problem is the labor cost of evacuating and recharging the system correctly. Has anyone else ran anything similar with a Toyota/lexus vehicle? Any pointers?

I've found forum posts on a tacoma forum outlining the same behavior, on new and higher mileage trucks. In one case it was overcharge, but I think in the others it was the compressor. In one instance however the compressor was changed and the noise persisted... What I'm not clear about is if they just changed the compressor or the compressor and the pulley clutch system.

 

[CleanSump]

I'd check the clutch gap and condition of the faces first.

 

[JavierH19]

Probably too wide of a gap. Usually it's as simple as removing the center bolt to remove the plate and shim it and make it engage good. Plenty of videos on how to shim an ac clutch. They usually have a good amount of clutch material left. does this happen with the ac on at startup so the engine is spinning at over 1k rpm's? Even on good clutches it can make that sound if it engages at a high speed which is rough on it. I turn my ac off before shut off and on next start up engage it after the engine has settled down and I've put it in gear to get the rpm's to 500 so it doesn't engage while spinning fast.

I won't bother to pull the compressor off just for a clutch. I'll be ready to order new densos as rock auto has them $200 while the cheap crap is $140 so no reason to go cheap there. The idemitsu denso nd 8 oil is apparently the best of the best and extends system life by a lot compared to generic pag oil that's low quality in comparison. If I can get an ambulance package condenser i might also replace that.

I also jumped the low side switches to make them engage less and opted to keep the fan speed a little higher than normal so the pressure doesn't drop too much. They'd only disengage for a few seconds after coming to a stop then engage again which is pointless. The pressure just barely goes below threshold and I did check they were charged and also not icing up the suction line or evaporator which are reliable sign the charge is low at least on non variable displacement systems.

 

[STL_G8GT]

Probably too wide of a gap. does this happen with the ac on at startup so the engine is spinning at over 1k rpm's? Even on good clutches it can make that sound if it engages at a high speed which is rough on it. I turn my ac off before shut off and on next start up engage it after the engine has settled down and I've put it in gear to get the rpm's to 500 so it doesn't engage while spinning fast.

I won't bother to pull the compressor off just for a clutch. I'll be ready to order new densos as rock auto has them $200 while the cheap crap is $140 so no reason to go cheap there. The idemitsu denso nd 8 oil is apparently the best of the best and extends system life by a lot compared to generic pag oil that's low quality in comparison. If I can get an ambulance package condenser i might also replace that.

I'm going to check the gap next week when I get back, but I am going to have the car started and let it idle down before AC is turned on after being off all night to see if the noise still happens. If it doesn't show up at 600 RPM, but it did show up when it was first started and idling at 1200, does that further point towards shim adjustment needed vs any other issue? For one test, I did let it idle down to ~600rpm once before I turned the AC on and I didn't hear the noise, however the car had only sat for about 4 hours at that point. The overnight cold start I think it's really the most consistent behavior.

Definitely would replace the condenser with a denso if it comes to that. You're right, the cost difference wouldn't be worth it. And based on the age of the vehicle I would do the condenser as well.

 

[379KITTY]

Something to consider in regards to turning A/C off/on etc prior to starting vehicle - with CCOT systems that compressor is being commanded on/off repeatedly at higher rpm's highway speed etc. Designed to do that. So whether it starts/stops with engine or not probably doesn't matter. Some (if not all?) variable displacement compressors don't cycle, so maybe an argument could be made there but I'm guessing clutch slip alleviates any shock related issues.