AC compressor choices
 

Getting an odd low rhythmic growling noise for a few seconds (best way I can describe it) on start, a second or so after the engine fires up and stabilizes. It’s not happening all the time, but is clearly tied to something spinning and goes away after a few seconds. Both my fan clutch and ac compressor are original, so one or the other is my prime suspect for a bearing starting to go.

I’m trying to narrow it down by only starting the car with the climate control Off, which would point to the compressor if I can’t repeat it in this configuration. That said, I see two makes of compressors at FCP: Denso and Mahle/Behr while ECS Tuning lists a Nissens compressor. Any recommendations between these three, if that’s where I end up? Denso is OEM I think, and while none are crazy money, the other two are about $100 less than the Denso.

I’ll likely throw a new fan clutch and fan (design change at some point after mine was made) at it anyway too, since mine is so old. I worry about the fan coming apart at high rpm.

How is your idler pulley?
Mine start making a similar noise and replacing it took care of that, although my A/C shredded itself internally about 18 months later...[emoji848][emoji28]

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Brand new with the motor swap, so 1.5 yrs old. That’s not to say it couldn’t be failing though. AC tensioner is new too.

I went with a Denso for my replacement. So far so good but we're past the hot weather here and it hasn't gone above 45c so we will see next year...

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FCP says Denso is the OE mfr, so the smart choice. Even with the warranty I think it’s a pita of a job on the v8 cars so maybe not worth saving $100 bucks for a non OE compressor and possibly having to redo it sooner.

Pre-facelifts had the Denso while the post-facelifts had Calsonic Kansei's IIRC.

I would go with Denso among your choices.

I tried a Nissens on a 3.0 and it has a growling noise that the OEM Calsonic did not have. I have since heard from other owners that have experienced similar. Cools as it should, just noisy compared to OE.

I get a bit more noise now after replacing with the Nissens as well. I thought at first I had too much refrigerant system but no. The quality 'looked' really good. The noise is more when there is less heat load so maybe they have a different calibration or there is something different with the variable displacement that pumps too much or doesn't let the volume go down far enough when not needed ?? I have 2 or 3 seasons on it and has worked fine other than the noise.

Same here, last thing I thought the noise would come from was the new compressor.

I changed out the AC belt, idler and tensioner assembly, still noisy. Then had refrigerant recovered and recharged to the proper weight along with the oil, still there, so compressor it was.

No idea what's causing it, and like yours it works fine except for the noise.

I get the feeling that maybe it was done on purpose so that the compressor is never running at zero volume, maybe to avoid having it get stuck at that position. The geometry is probably such that it needs the most force to move it from zero and that would explain why sometimes people are able to get it working (when stuck) by revving the engine.

My original compressor was stuck at full volume.
I actually did buy a replacement control valve to replace on the original compressor and put that back in but never got around to it and gets more unlikely as time goes on.

Mine was intermitently cooling, this was my first variable displacement compressor car so took me a bit to figure it out.

That sucks if it was engineered to do that at the expense of NVH. I'd have gone for a different brand if I'd known.

Check the secondary air injection pump. Mine howled for a few seconds at start up. Ended up going through three of them. Two low cost ones made noises too. Ended up with RockAuto's most expensive air pump to stop the growling. You can unplug it and put 12V on to test it.