I'm wondering what the operating temp of the S320 should be. Tonight I was driving home, and the outside temp sensor was readying 16C, and the water temp gauge was reading almost 100. I had no AC on. I also couldn't get the car to cool down in traffic today w/o the AC on. It was running around the 110c mark or higher.
How does one check a rad for cold spots??
I replaced the h2o pump and tstat 2 years ago, but how does one check for coolant flow??
Fan clutch was replaced recently....

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Too many people tip toe through life, never attempting or doing anything great, hoping to make it safely to death... Bob Proctor

'95 S320 LWB
'87 300SDL
'04 E500 wagon 4matic

Sounds like a aux fan issue or a/c drier sensor or temp sensor failure.

I verified that the AUX fans are working properly. At temps read by the CCU, they turned on at 102C. Right in spec with what I read in the manual...
How would you test the AC drier sensor and temp sensor??
Right now, I'm running the test to see if the rad and h2o pump are working properly....

__________________
All it takes for evil to prevail is for good men to stand by and do nothing.

Too many people tip toe through life, never attempting or doing anything great, hoping to make it safely to death... Bob Proctor

'95 S320 LWB
'87 300SDL
'04 E500 wagon 4matic

While standing, I turned on the AC, and it idled up to about 100C on the dash gauges. I didn't rive the car, just let it idle. I then checked the hoses with an infrared thermometer. The top hose was 93-94C, and the bottom hose was 89-90. The cooling difference on the heater core hoses was about 20 degrees with the heat on max, and the fan going full tilt.
So, I guessing that means a new rad. Do shops do a good job cleaning them, or do I have to get a new one??
If new, the question is, Behr or Nissens??

__________________
All it takes for evil to prevail is for good men to stand by and do nothing.

Too many people tip toe through life, never attempting or doing anything great, hoping to make it safely to death... Bob Proctor

'95 S320 LWB
'87 300SDL
'04 E500 wagon 4matic

Not an aux fan issue if your temps while driving are too high. Aux fans have no effect above about 20 KPH. Others can advise you better about radiator replacement, but it does seem that the temp differential between upper and lower rad hoses should be more than 4-5 degrees. I've always been told it should be in the range of 15-20 degrees. Maybe a radiator expert will weigh in.

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1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't