Curley, I've got three of these cars, '87 with OM603 and two '95's with OM606NA. None of them need the aux fan running in the summer heat, unless the AC is running or I'm carrying a big load or running fast on the highway up hill and then suddenly slow down.
Just driving around town at 75 deg F, with no AC running, the car should not need the aux fans running. I disagree, you've got evidence that the t-stat is failed. They can fail right out of the box! In your place, I would remove the front bumper and the fan shroud and clean out the leaves and bugs between shroud and condenser, pull the radiator and clean between radiator and condenser, spray your garden hose through both while you have it all apart, and then pull the t-stat and check it for function. Here are the specs from MB: OM601, 602.91, 603.91: begin opening @ 85 +/-2 deg C, minimum stroke 8mm @ 94 deg C If the AC refrigerant has leaked down, then only the high speed function of the aux fans will work. ------------- Max Charleston SC On Fri, Mar 13, 2020 at 11:38 PM Curley McLain via Mercedes < mercedes@okiebenz.com> wrote: > because the problem is not the thermostat. On this one, the radiator is > blocked by a shroud, except for where the 2 fans are. I'm guessing that > is to keep bugs out of the radiator. So without the fans running, it > runs too hot. when the fans run it is fine. Larry put a new > thermostat in it not that long ago. If I had evidence of a thermostat > problem I would change it. so far it is quite clear: Fans running, no > overheat. Fans not running, overheating. With the sensor on top of > the engine plugged in, the fans never run. THat is a problem. When > that sensor is unplugged, the fans are intermittent. > > If the R134a has leaked out, would the low pressure switch cause the > fans not to run? Seems to me that the fans should be independent of > the a/c, but obviously they are linked at the drier. Fans should run > when the A/c is off. > > _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
