Hello:

With the motor running and the air conditioning on, there is a intermittent ticking noise that comes and goes. It may be the compressor coming on and going off. Any help?

Jarm

 

The ticking is only with the AC on? ACs make noise but it shouldn't be intrusive.

 

The car does have direct injection..that does have a slight tick to it. If the ac compressor engages, you may hear a quick "click". I sometimes hear my exhaust manifolds clicking or ticking depending on the weather, but it's pretty slight.

 

With 32 valves and 16 injectors, it's surprising these cars don't "tick" more than they do.

The ticking with the a/c on could be the compressor. The compressors on these cars don't use a clutch. Instead, they have a variable angle swashplate inside the compressor that lets it pump only as much refrigerant as is needed to cool the evaporator. This makes it normally very quiet and smooth. These compressors do use either 5 or 6 little pistons and valves which can make a little noise, mostly at high demand pressures.

If this ticking is a recent development and the compressor is suspected, get a good a/c tech to listen to it. A failing compressor, caught early enough, can often be replaced before it gets really bad and sheds metal into the system. Once that happens, things will get very expensive.

All that being said, I don't know of any compressor failures in LS 460's yet.

 

Check your exhaust manifolds for leaks. This ticking/clicking noise was common in the Toyota/Lexus trucks and SUV's, caused by cracks in the manifolds.

Just saying.

 

I wasn't sure if they had the variable displacement compressors...good to know.

 

The ticking noise is at idle while the AC is running. The sound comes on for 5-7 seconds then shuts off. It does this all the time when the ac is running. When I turn off the ac it stops.

jarm