This is my first MB which I wanted for a long time. I have had this E320 for about two months now and have been chaning fluids, brakes, etc. Monday night the low coolant light came on and it was indeed low on coolant, leaking from a 1/4" split in the bypass hose. So I replaced all three hoses. I was relieved to see yellow cooland come out when I pulled the bottom hose. I buttoned it up, topped it off and burped it with the top rad hose.

This process has made me more aware of the temp gauge while driving. The temps do not seem any different than before the coolant leak but I wonder what the norm is and what the marks in the gauge indicate. Are the ticks on the gauge 40-60-80-100-120? Obviously 40, 60, 80 and 120 are marked. Is the one between 80 and 120 100?

Morning temps here are low to mid 70s and the w/o AC turned on the gauge splits the center of the 8 of the 80 numeral. That seems fine. At afternoon rush it has been more like 90-95 and at that time with air on the gauge splits the top of the 8 when moving and will creep up to the next tick in 10 minutes of freeway stop and go. If the tick mark between the 80 and 120 indicates 100 then does that seem a little hot? Should I be a little concerned?

Thanks again for the forum and for the experienced feedback.

Regards,

__________________
Tim Benner

00 ML320 170K
95 E320 wgn 160K

The MB spec thermostat for these cars starts to open at 87C and should be fully open by 92C. If memory serves me correctly, high aux fans should come on at 107C then go off again when temp drops to about 100C. (low aux fans are triggered by ac refrigerant pressure only)

During hot weather city driving with the ac on, both my cars (94 E320 wagon, 95 E320 sedan) settle in around 95c--needle at the top of the 8. When stopped in traffic, it is not uncommon to see the temp bump up to the aux fan trigger point. My sedan has a resistor that lowers the aux fan temp trigger to about 100C. Sitting in traffic, I can tell by the temp gauge when the aux fans have started.....

I believe temperatures in the 90C to 100C range are normal for summer operation with the ac on.

As far as the markings are concerned, I have always thought the mark between 80 and 120 is 100. But now that you ask the question it does make me wonder a bit.

Forum member Jim Forgine has some really good information on the aux fan story. Here's a link to his site. (Jim--hope you don't mind)

http://pages.prodigy.net/jforgione/MB_CTS.html

Thanks! It is a relief to hear that mine is operating the same way yours is. No need for concern. The car is slowly getting to the shape it deserves to be in. The only thing I may have to "cobble" (or is that fabricate?) is the broken hinge on the armrest / phone compartment. The whole thing will be replaced if a reasonable one becomes available.

Thanks again!

__________________
Tim Benner

00 ML320 170K
95 E320 wgn 160K