Normal operating temperature?

[spinedoc]

Just had some overheating issues, replaced the thermostat and car is running within tolerance. But it seems to be running hotter than before this problem, only I never really paid attention to the guage before so it might be me being paranoid.

What is the normal operating temperature range for a SL500? Right now in stop and go traffic with 90 degree weather it goes up to 100 degrees celsius (the hash mark between 80 and 120), a hair over if I have the AC on. I seem to remember it would only go up to 90 or so before, but not sure. It sure is blowing a lot more heat out of the center console than it usually does, but it was a hot day yesterday.

[jjrodger]

Mine runs at about 95-97 deg C at the moment, but the weather is warm here and I also have a different engine to you. I have read in another post that you needn't worry unless it goes over 120.

[LeaUK]

Interesting topic guys as I was just about to canvas opinion on this too. According to my manual 100C is just fine with even the occasional 120C is OK!

SpineDoc - what was the syptoms that led you to change the thermostat? Thermostats usually stay open causing a lengthy wait for heat on cold days, or refuse to open causing the engine to quickly overheat?

I've just repaired my Viscous fan (see here ) and my 500 now runs at a consistent 85C. I understand that most petrol cars are designed to run around 90C-95C and so wonder why mine is cooler, however as I didn't replace the viscous clutch with a MB part (too expensive) the characteristics have changed somewhat - I guess for the better!

Firstly, check when the viscous fan starts to engage (should be around 95C) then the aux fans (assuming A/C is off) should engage around 100C - again mine weren't until 110C so I've ordered a new sensor (16UKP). Whilst I was at benz I thought I'd order the other two coolant temp sensors too as I also suspect their characteristics have changed over the 11 years, especially with excessive temperature cycling (no viscous fan) for who knows how long!

Lea

[spinedoc]

Originally the car was running a hair below 120C, it would not overheat, but it made me very nervous. Before that I cannot remember, but am sure it ran in the regular 90-100 range on average. I took it to an indie and since it was Friday afternoon he only had a couple of minutes for me. He jumped the aux fans so they were on all the time and told me to come back monday. Thankfully I found a MB dealer that was open on Saturday. Jumping the aux fans blew out both of the fan relays, had to replace them as well as the Tstat. I am wondering if maybe the relays were blown before and it was not the Tstat, but the dealer said is still ran too hot after they put the relays in so the Tstat did help somewhat.

Anyhow it runs to spec now according to the tech forum so I am not worrying about it anymore.