E320 Normal coolant temp/ reset check engine light
 

My E320 engine temprature ranges from about 100C-115C on cool dry days. I have checked the fluid level, radiator cap, fan clutch and aux fans. Everything seems to be normal.Is this temp range normal for this car?

Also, is it true that I can rest the check engine light by disconnecting the battery for 30 seconds?

Any help is greatly appreciated

Jim

Yes, your check engine light should reset when disconnecting the battery.

Change the coolant fluid. When was the last time it and the thermostat was changed? Make sure that the fans are turning on supposed to. You can do a search and find a LOAD of info on this topic. Good luck,

Which chassis/yr E320 ?

Thanks David C. Klasse I am going to try the cheap fix of a thermostat and coolant first. I still would like to know the standard operating temp.

Arthur Dalton----My car is a 1996 E320

The thermostat is usually 87C, they'll normally run right around 80C on the gauge, maybe a little higher. Haven't had big thermostat probs on 104 engines like yours. Possibly there is a build up of leaves and other "krahp" between the A/C condensor and the radiator. Also I believe on this particular model, there are 2 fans in front of the radiator, the one on the drivers side has the motor, and the one on the passenger side is driven off of the drivers side via a thin rubber belt. We've had some problems with the belt coming off. Just raise the hood with the engine off, spin the hub on the drivers side fan, and the passengers side should rotate also. If the passengers side does not rotate, this may be part of the problem.
Gilly

Yup, mine is about the same. I have the same M104 motor found in your E320 in my C280, and mine is usually about 85 C or so when cruising... but will easily shoot up to 100 or so upon stopping after a long drive.

Only once did the temp ever get to 110, that was on a long ascending hill, doing 80 mph, with 3 passengers (4 people) including luggage, and a 100 F exterior temp. Anything above 110 and I'd worry a little!

Good luck. And of course, don't forget splitting the coolant/water mixture. You can even try 45/55, coolant to water, respectively, for a slightly lower operating temp.

NOTE: ONLY USE MERCEDES-BENZ COOLANT (from dealer, about $11)!!!