Vibration with AC on (1 Viewer)

[musthave]

Working on a 97 Land Cruiser for a friend. Vehicle has 270,000 miles. Runs great.

While idling the vehicle is fairly quiet. If you turn on the air conditioning there is a vibration felt and heard. If you put it in neutral it is reduced. If the compressor turns off, it is reduced.

Compressor is operating normally, the belts are brand new.

I have determined that it is not a driveline vibration. It occurs while parked.

Any idea as to what the overall vehicle vibration would be from? I’ve never experienced anything similar in other Cruisers.

 

[Desert Dino]

Dose it pull the idle RPM up when the compressor is on?

 

[musthave]

Dose it pull the idle RPM up when the compressor is on?

Yes, about 300 RPM or so.

 

[bhsdriller]

seems normal to me, think mine does it. Can definitely tell when the AC comes on/off

 

[musthave]

If it were mine, I wouldn't care. Working on a friends cruiser and his wife might be a little pickier than I am though. Trying to see if I can figure out what it is. So far I am thinking maybe the clutch on the compressor is causing it.

 

[Zjohnsonua]

Following, as the GF's 80 does this very thing and it drives us both nuts. I've been tinkering with a few things trying to find the cause to no avail.

 

[TJ Vines]

Same problem here. 96 LX450 175k miles. General tune up (plugs, wires, rotor, MAF cleaner) did not fix the issue. She'll idle up from a smooth 680rpm to a rough 900-1000rpm. Only occurs with AC on. Hope this thread can help us all but I've accepted it at this point - other more pressing issues I guess.

 

[thatcabledude]

Swap the motor mounts?

 

[musthave]

Swap the motor mounts?

Hmmm, yea, hadn't thought of that. They're probably original and likely need to be replaced. Will look.

 

[TJ Vines]

Swap the motor mounts?

Thought about that but didn't see any movement or swaying of the motor - if the mounts were bad would you expect to see movement?

 

[TJ Vines]

Vibration at idle - with A/C on.

I had a friend in the truck the other day and he asked why the truck was vibrating so bad at idle. It goes away when the A/C is not on. I guess I did not notice the gradual change. Is this a sign of the compressor going bad? While changing the oil today, I listed to the truck at idle...

forum.ih8mud.com

Came across that thread

 

[Tools R Us]

Could be the clutch bearing, remove the belt and see if the pulley turns smoothy, check for play, wobble.

 

[nukegoat]

How's the AC performance?

 

[TJ Vines]

How's the AC performance?

Pretty dang good during this Midwest heat wave

 

[uscmas412]

What brand is the compressor? PO put in a four seasons aftermarket and I have the same issue. I recently replaced motor mounts, belts, fan, fan clutch and that did not help. This compressor is one of the last non-OE pieces of equipment I have, looking for a reason to be rid of it.

 

[COYS]

Had same issue on a ‘97 and asked here. No one had a solution that responded. It was annoying af.

 

[Gascan]

Just spit-balling here, but perhaps it's his exhaust system, vibrating due to broken exhaust mounts (the rubber sort)?

 

[MattL]

I get this same issue - 96' ~260K mi.

 

[WTFish]

Glad it’s not just me...

 

[flintknapper]

Each person with this issue should check to see if it is RPM dependent (appears and goes away in a certain rpm range).

IF so...then it might simply be harmonics and might not be much you can do about it. Worn parts would be another matter (clutch bearing, tensioner, damaged pulley, worn belt, belt tension).