fLex0vIL

Hello everyone ! HELP PLEASE 🥂
I have 207 s500 and got its engine mounts changed and with it got the engine oil and oil filter changed and also the air filter changed. Used mobil 1 oil and genuine oil and air filters. and the abnormal vibration was gone and oil and filter was the regular maintenance. Next day got the pulsation dampener changed as my car was making too much humming sound while driving and after change the sound was gone and it was quite and smooth, But what happens then was my car started making some loud noise (growling type of) while starting. the sound will only be heard when inside the car and out side you cannot hear it and also it stays for maximum 1 second then gone. and it will come if the cars engine is switch off for for about 10 minutes or more. and if you start the car right after switching off the engine no noise at all and you will get a smooth start.. was wondering what it can be.. my mechanic is unable to diagnose.. so far what he did was gave some exercise to the ABC system and my car struts kept on going up and down for 15 mins one by one.. and as per the mechanic if there is any air in the ABC system it will go.. but unfortunately the sound is still there comes every time i start the car and go out with 1 second and the drive and engine sound is fine... I shell me thankful for your valuable comments... Thanks Nikolai

Arrie

I had a pick-up truck that made kind of sound you describe. It was from the air conditioning.

Easy troubleshooting. Turn your A/C compressor OFF next time you park overnite. It should stay off at next start. See if it makes the sound.

wizee

Did you ever figure out what the issue was?

BOTUS

these are budget designed to fail cars sold at a premium, by crooked accounts and a marketing team

all the drive pulley's disintegrate as the bearings are made of cotton wool,
the AC pully bearing is made of chocolate
the AC system sound like a faulty gearbox when low on gas (which happens as they used economy spec bacofoil on the condenser)
the PAS pump is noisy
the water pump sounds like its from a 1968 200k mile land rover that's not run for 40 years
the alternator would disgrace a lada
the gearbox TC will self destruct
when the engine mounts fail it will make you think the world ended

all in all I'm surprised with the suspension rubbers and bushes made of the special stuff all car manu use today (which disintegrates in 5 years) and the suspension fails every drive, I'd have thought you didn't have much time to hear noises ?

.

wizee

Lol, I know you hate these cars, but just leave us in peace. They’re getting older, and things fail in any car. You think aging Lexuses and Toyotas don’t get these same issues? Two of my friends recently had to replace their AC compressors on their less than 10 year old Toyota and Lexus respectively.

My 14 year old 145k km CL550 measures 43 dBA inside at idle, same as several testers reported when new, and also 4 dBA quieter than my W140 S500 in the same conditions, which is also a pretty quiet car. My idler pulleys are fine, my water pump is fine, my suspension bushings are fine, my transmission and torque converter are fine, my engine mounts are fine, my alternator is fine. Sure, there are newer cars that are quieter at idle, but this is still pretty good, and better than most cars sold in 2007. The car rides great, and is impressively quiet on good pavement. The Michelin Pilot Sport A/S 3+ tires are noisy on rough pavement, but that’s not the car’s fault, and the tires were optimized for grip over noise.

tonylinc

My 2008 S550 is the most rock solid car in existence. Well, almost. I prefer it over almost all the new cars out there. My dark chocolate idler pulleys are fine, my water pump is fine, my pancake syrup suspension bushings are fine, my transmission and torque converter are perfect, and believe me, they get a workout because I don't believe in allowing carbon buildup inside the engine. They like to run, and I mean really RUN. My waffle cake alternator is fine. I did get new engine and trans mounts a year ago, but given their job and how they work, that's okay, and they don't cost that much. My blueberry water pump is perfect and so is my wonderful A/C. It's not like a 1966 Chevy Impala. With the depreciation, I think these cars are some of the best deals in used cars you can get, as long as you are smart enough to do some work on them yourself and not allow yourself to get ripped off by crooks, which can be genuine dealerships and/or private shops. Every time I drive any of my Mercedes, and I own five, I feel privileged to drive something that cost $100,000 or more when new that still looks great and still drives like new. My S550's black leather interior is beautiful, and if the last 13 years are any indication, will last another 25 years. Looking at a 2008 S550, if it's clean, it looks like a three years old car, certainly not a 13 year old car! I'm thinking the botus guy is a Lexus salesman LOL... Maybe he had a bad experience with a Mercedes dealer which is understandable; the dealership near me committed fraud and theft in one visit and that was just for a PPI!!! Never going back there!
There is an air pump that works for about a minute at start-up that pumps air to the catalytic converters to help them warm up faster, or to reduce emissions, that might be what you are hearing. If the noise isn't too loud I wouldn't even worry about it.

wizee

More on topic, my 2007 CL550 has symptoms similar to yours. There is a slight groan coupled to engine RPM most audible from inside the car for about 1-2 seconds on startup (when the AC is enabled), and there is a very subtle whining noise (when the AC is enabled) between 1300-1500 RPM, most noticeable at 1400 RPM. Most people wouldn't think anything of it, but I'm very sensitive to any unusual noises. The whine is most evident when it's hot outside and the AC needs to do something.

As per @Arrie 's suggestion, I tried turning climate control off while the car is running, then turning off the car and leaving it for a few hours. I experimented with a few startup and drive cycles with climate control off, with a few hours in between attempts. In all the startups with climate control off, the slight groan only lasted maybe 0.2 seconds and maybe I'm mixing that sound up with the secondary air pump starting. Also, no 1300-1500 RPM whine with climate control turned off. I turned the climate control back on, and the subtle whine around 1300-1500 RPM returned after maybe 15-20 seconds. Turned climate control off again, and the whine at those RPMs disappeared immediately. I also tried turning the car off with AC enabled, and restarting it half an hour later - sure enough, I had the 1 second slight groan on startup.

Based on my experiment, I think @Arrie is correct that my AC compressor is starting to fail. The noise is pretty subtle and it still cools well, so I think I'll let it be for a while, but at least it feels good knowing what the issue is.

For some background, I bought my 2007 CL550 recently "as-is" for a cheap price from some low-end small used car dealer. It was in rough shape due to ridiculous neglect by the previous owner, but I've mostly brought it back to health. It needed an engine oil cooler gasket (was leaking), ABC pulsation damper (to fix a louder and more persistent whining noise around 1500 RPM), and transmission mount (to fix severe vibration in the seats above 2000 RPM). These were all relatively cheap and easy fixes, but the car was neglected so the little issues just piled up over the years while the previous owner just kept driving it. The AC was also not working (compressor wouldn't even try starting). My mechanic found there was almost no refrigerant in it, but couldn't detect any immediate leaks when testing it. He went ahead and changed the AC compressor oil, and also evacuated and recharged the system. This brought the AC back to life, and it has been cooling great ever since. There's probably a slow leak somewhere (else why would it have been empty when I bought it?), but at least for the past month it has been holding the charge and cooling great. However, I suspect the compressor was slowly damaged by the previous owner running it with low refrigerant over an extended period, and this is probably why I have the slight groan on startup and 1300-1500 RPM whine.