SL/R230: Intermittent overheat issue
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O7 SL550
Intermittent overheat issue
Hi fellow R230 owners,
I'm hoping someone can offer some wisdom with an intermittent over temp issue I'm having with my 07 SL550. Temp is steady for most of the time then in very short order goes up to 120C. After 10-15 minutes(varies) the temp will drop back to ~94C(normal) and be rock solid for the rest of the day. I replaced the thermostat and temp sending unit, but problem remained.
I have a Foxwell scanner that caught a 2366 and 0694 code for the M4/7 suction fan malfunction. Today as I was running a quick scan, I noticed the temp was creeping past normal while idling, and witnessed that the engine and A/C was calling for fan but the fan was not spinning. I turned the engine off but could not get the fan to spin using the Foxwell scanner. When I went back a few hours later, the scanner controlled the fan as expected; except that it wouldn't spin the fan at 10% - only functioning between 20-90%.
I believe this is going to be the control unit on the fan - which means I will have to buy a fan (~$500). However, I can't help but suspect that a faulty ECM could also cause this issue. Does anyone know how I can positively identify if the fan or ECM is causing this issue. I don't have a scope.
Any help is greatly appreciated!
-Craig
I'm hoping someone can offer some wisdom with an intermittent over temp issue I'm having with my 07 SL550. Temp is steady for most of the time then in very short order goes up to 120C. After 10-15 minutes(varies) the temp will drop back to ~94C(normal) and be rock solid for the rest of the day. I replaced the thermostat and temp sending unit, but problem remained.
I have a Foxwell scanner that caught a 2366 and 0694 code for the M4/7 suction fan malfunction. Today as I was running a quick scan, I noticed the temp was creeping past normal while idling, and witnessed that the engine and A/C was calling for fan but the fan was not spinning. I turned the engine off but could not get the fan to spin using the Foxwell scanner. When I went back a few hours later, the scanner controlled the fan as expected; except that it wouldn't spin the fan at 10% - only functioning between 20-90%.
I believe this is going to be the control unit on the fan - which means I will have to buy a fan (~$500). However, I can't help but suspect that a faulty ECM could also cause this issue. Does anyone know how I can positively identify if the fan or ECM is causing this issue. I don't have a scope.
Any help is greatly appreciated!
-Craig
Last edited by CD07SL550; Jun 14, 2022 at 01:28 PM.
