Hello. I have noticed rpm increase on idle when AC is turned on, btw. It is so hot outside, outside temp is >29 celsius. Rpm increase is from 750 to 1000 rpm. Is it normal??
AC on means that the AC compressor is now engaged and loading or stressing the engine a bit more as it is now working and compressing...(extra work required..)
If a normal idle shows 750 RPM without this AC load, adding this extra load would or could stall or stop engine if it did not accommodate this extra load..
A touch more HP (with increased RPM..) to accommodate the added load of the AC compressor....seems logical to me...
mine increases 750 to around 800. but I heard clogged ac compressor or anything makes the serpentine belt difficult to turn could cause higher rpms. It is rarely above 25 celcius here so I don't know if it'll rise to 900-1000 rpm above 30 celcius.
Yeah, I'm thinking that's way too much RPM rise. A 50 RPM rise would be more reasonable and expected. This shouldn't change that much depending on temperature. The AC compressor either runs or doesn't. The load, AFAIK doesn't change with different temperatures.
The clogged AC compressor theory sounds reasonable. Too much pressure/gas in the system, clog in lines or an AC compressor issue?
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Mercedes-Benz Forum
7.6M posts
693.6K members
Since 1999
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!