KurumaGOD

Well my driving temp is usually around 85-95 degree c... If i stop the car and shut it off...and start it up again few minutes after...the oil temp usually went up to 100 degree c...is it normal? yes it will drop once i start driving... One of the mechanics told me that it is okay as long as it does not go higher than 120... But i'm still kinda worry about it... What might be the problem thats causing the temp to be higher than usual like 80? Or is it that OEM inline 6 engines do not have good radiator?

regardz,

k-god

DougandhisC280

The engine heats up after you turn it off because it gets no air circulation. Think of it as you running. While you're running, you usually aren't that hot. But if you stop all of the sudden, you will get hot. Nothing wrong with it, just physics.

suginami

100 degrees is not hot for your car. Not even close. At 100 degrees, your thermostat is not even in the fully open position yet.

You have an 87 degree thermostat, and that is the temp that your t-stat starts to open. I'm sure your car should be running between 87 and 92 degrees most of the time, and will probably run about 100 degrees at an idle in hot weather. Here is what the CD says about the cooling system and temperatures on C-class M104 engines:

Thermostat will start opening at 85 to 89
Thermostat will fully open at 102
Viscous fan clutch will cut-in at 96 to 104
Viscous fan safety cut-off will ocurr at engine rpm 4500
The same will ocurr at fan rpm 3250
Electronic fan (1st stage) will cut in at 16 bars of refrigerant pressure) or 100 C via ECT sensor
Electronic fan (1st stage) will cut out at 13 bars or 95 C
Electronic fan (2nd stage) will cut-in at 115C or on the a/c circut at 20 bar
Electronic fan (2nd stage) will cut-out at 107C or on the a/c circut at 17 bar
A/C will go into 50%on, 50%off cycle (20 seconds interval) at coolant temp 121 to 123
A/C will go into emergency shut-off mode at 126 to 128
Pressure cap will open at bar 1.3 to 1.5
Coolant temp max is 130

Remember that water boils at 100 degrees celsius, but with a 50 / 50 mixture of water to coolant, your boiling point is raised to 120 degrees, and the car isn't considered to be overheating until the temp exceeds 130 degrees.

MB designed these cars to run in a specific temperature range, and 100 degrees is very comfortably within that range.

mrjones

The M104 inline 6 runs "hot", I was also worried about that at first. I've been assured that it's completely normal, even the 105°C I see on a hot day.

KurumaGOD

Thx for the replies guys...

It seems to be a normal after all...thats a good piece of information there... Now i'm worry free...kool!

regardz,

k-god

suginami

I wouldn't say that the M104 engined cars run hot. They run at the same temp range as W140 and W210 sedans.

What Mercedes has done is mess with the temp gauge so that it doesn't accurately reflect the real temp anymore:

On W210 sedans, Mercedes has "engineered" the pointer so that it stops at approximately 95C at temperatures between 95C and 115C. Temperatures in this range are not considered critical. The correct temperature is only displayed again from a temperature of 116C. This prevents the driver from being disturbed by excessive needle movement in the display. The warning range starts at 116C.

See? Mercedes figures it is a good idea to fool owners their car is running at 95 when it could be really 115.

Maybe they've been reading too many posts on these forums for W124 and W202 cars with owners frantic that they're running too hot at 100 or 105...