High-Pitched Buzzing Sound SCV6

[cjm41]

I’m trying to figure out the source and cause of a new and peculiar sound I noticed my 2014 LR4 making when I pulled into the garage. I’ve only had the truck for about 2 months and haven’t driven it a ton (500 miles or so, mostly highway) but this is certainly a new sound.

as with many Land Rovers, the truck makes weird sounds, nothing alarming to someone used to quirky vehicles. Noisy fuel pumps, loud lifters, etc. I’m no stranger to vehicles with “character”.

But this is a new one. For some reason my first sort of reaction was “fuel pump” but I’m basing that on gut and have no evidence to back it up.

it sounds almost like the sound when you left a key in the ignition of a car from the 70s or 80s. It’s the sort of higher-pitched steady buzzing.

anyone have any thoughts on this?

 

[LB Bill]

EAS/compressor? Do you lower it to pull into the garage? I have to, and the system 'buzzes' for a bit while it cycles...sometimes continuing until I turn it off. It doesn't seem that high-pitched though. (the rest of the 'noise' seems normal lol).

 

[cjm41]

EAS/compressor? Do you lower it to pull into the garage? I have to, and the system 'buzzes' for a bit while it cycles...sometimes continuing until I turn it off. It doesn't seem that high-pitched though. (the rest of the 'noise' seems normal lol).

i don’t have to lower it to pull in. It’s a close call, but no access height necessary.

I think it only gets a little louder as I walk to the rear of the truck because the engine sounds are less predominant.

although now I’m going to try to replicate it and really listen for it around the compressor.

 

[jlglr4]

That is a puzzling noise that would clearly drive me insane. Sounds like almost a ringing noise to me, which somehow is familiar - but I can’t put my finger on what it reminds me of. Does it change with engine speed? Does toggling the AC compressor on/off change the noise? Maybe a pulley going bad?

I have one of those super cheap mechanic stethoscopes that came with both the rod and a hollow tube with a cone. I find it pretty useful for tracking down the general location of noises, then switch to the rod to test specific devices.

 

[jlglr4]

Couple other thoughts - put a little pressure on the pcv cap to see if that changes anything - or point a stethoscope over there. Also - the supercharger snout - the coupler can go bad and start producing a metal-on-metal contact between the shaft and the coupler spring.

 

[cjm41]

Update: it’s the AC compressor.

Not sure if it’s failure is imminent or what. I’m going to continue to investigate but in the meantime I’m not overly concerned. AC is blowing cold and if the compressor fails I’ll replace it. I just hope it’s not something that would seize and lock the pulley, then ultimately cook a belt.

 

[jlglr4]

You might check your belt tension and look for any coolant residue or oil just to make sure the noise is not actually the belt slipping. Maybe pull the belt off and check the compressor pulley by hand for looseness - you won‘t get the clutch to engage, but maybe the pulley itself is getting noisy.