Hey Guys,
So the weather outside has been hot around here. Regularly, it gets to the mid-eights or low-nineties. As of today, my S550 has been running the main fan at what seems to be a very high rate (because it is noisy as hell) when I shut off the car and walk away. It does this if it has been running for any amount of time.
For instance, this morning I left home (so the engine was "cold") and drove to the sitter's house. That drive takes about 1.5 minutes, and is just over 1 mile away. The main fan ran for between 1-2 minutes.
So the question: Are others experiencing this in the hot weather?
My M5 does it all the time in the warmer weather. Should I be concerned at all? I feel the answer is "no," however since the fan runs so fast, it is just noisy and kinda makes my nice, classy car seem a bit stupid. 
That's all. No error lights, warnings, or codes thrown.
Thanks!
So the weather outside has been hot around here. Regularly, it gets to the mid-eights or low-nineties. As of today, my S550 has been running the main fan at what seems to be a very high rate (because it is noisy as hell) when I shut off the car and walk away. It does this if it has been running for any amount of time.
For instance, this morning I left home (so the engine was "cold") and drove to the sitter's house. That drive takes about 1.5 minutes, and is just over 1 mile away. The main fan ran for between 1-2 minutes.
So the question: Are others experiencing this in the hot weather?
My M5 does it all the time in the warmer weather. Should I be concerned at all? I feel the answer is "no," however since the fan runs so fast, it is just noisy and kinda makes my nice, classy car seem a bit stupid. That's all. No error lights, warnings, or codes thrown.Thanks!
If it does stop after a while it should be OK. I don't know about all these electronic thermostats but, in regular cars fans are (indirectly) tied to thermostats and when they go bad sometimes the fan runs unneccessarily.
A running fan is always better than a stopped fan
A running fan is always better than a stopped fan
RajwanyS550
Super Member
close
May 12, 2026
Quote:
So the weather outside has been hot around here. Regularly, it gets to the mid-eights or low-nineties. As of today, my S550 has been running the main fan at what seems to be a very high rate (because it is noisy as hell) when I shut off the car and walk away. It does this if it has been running for any amount of time.
For instance, this morning I left home (so the engine was "cold") and drove to the sitter's house. That drive takes about 1.5 minutes, and is just over 1 mile away. The main fan ran for between 1-2 minutes.
So the question: Are others experiencing this in the hot weather? My M5 does it all the time in the warmer weather. Should I be concerned at all? I feel the answer is "no," however since the fan runs so fast, it is just noisy and kinda makes my nice, classy car seem a bit stupid. That's all. No error lights, warnings, or codes thrown.
Thanks!
Have owned 5 benzs in the last 5 years. all S550. the fan is very noisy. sounds like a diesil engine in the summer. but it cools the heck on the inside. Originally Posted by IDriveAnM5
Hey Guys,So the weather outside has been hot around here. Regularly, it gets to the mid-eights or low-nineties. As of today, my S550 has been running the main fan at what seems to be a very high rate (because it is noisy as hell) when I shut off the car and walk away. It does this if it has been running for any amount of time.
For instance, this morning I left home (so the engine was "cold") and drove to the sitter's house. That drive takes about 1.5 minutes, and is just over 1 mile away. The main fan ran for between 1-2 minutes.
So the question: Are others experiencing this in the hot weather?
My M5 does it all the time in the warmer weather. Should I be concerned at all? I feel the answer is "no," however since the fan runs so fast, it is just noisy and kinda makes my nice, classy car seem a bit stupid. That's all. No error lights, warnings, or codes thrown.Thanks!
dont worry completely normal.
I don't know if relevant but check this out (credit to Konigster):
P-B-07.61/71 JUL07 Check Engine light is illuminated and the radiator fan runs constantly this fault may occur when the engine is at operating temperature and is then switched off and restarted immediately. The temperature sensor will be checked with DAS. Note you should always wait longer than two seconds prior to restarting the vehicle.
P-B-07.61/71 JUL07 Check Engine light is illuminated and the radiator fan runs constantly this fault may occur when the engine is at operating temperature and is then switched off and restarted immediately. The temperature sensor will be checked with DAS. Note you should always wait longer than two seconds prior to restarting the vehicle.
RajwanyS550
Super Member
close
May 12, 2026
Quote:
P-B-07.61/71 JUL07 Check Engine light is illuminated and the radiator fan runs constantly this fault may occur when the engine is at operating temperature and is then switched off and restarted immediately. The temperature sensor will be checked with DAS. Note you should always wait longer than two seconds prior to restarting the vehicle.
no engine light. the fan goes nuts when its really hot outside. right now we r at 100' + days of summerOriginally Posted by fbracer
I don't know if relevant but check this out (credit to Konigster):P-B-07.61/71 JUL07 Check Engine light is illuminated and the radiator fan runs constantly this fault may occur when the engine is at operating temperature and is then switched off and restarted immediately. The temperature sensor will be checked with DAS. Note you should always wait longer than two seconds prior to restarting the vehicle.
it is normal.
Member
Same goes for my S class and my friend's CL
Figured as such thanks all. Just loud.
