Mutiman

I own a 2011 GLK350. Purchased new from Weber Motors in Edmonton AB. Canada. Developed a problem with the cooling fan running at max. everytime the vehicle is started after having plugged in the block heater. The fan shuts down after a few minutes when engine is turned off but starts again with any restart for about the next 24hours. Vehicle water temp gauge registers normal at startup and then reaches running temp after a few km's travelling. Engine warning lamp also turned on after 2 - 3 days of this. Went back to dealer 4x for warranty repair: everything from temp. sensor replacement, to fan motor and control. Latest repair- software upgrade. Still waiting to get car back. Weber Motors and MB Canada are at a loss to explain what's happening. Weber motors did say that there were other GLK's with similar problem. Not aware of any recall regarding this. This of course plays havoc with fuel consumption whilst fan is running at max. all the time. Problem is no-one has an answer and I need to plug block heater in. Vehicle will freeze at these temps.!
Worried that software tweak will merely mask a problem rather than solve anything. Anyone else encountered this? Any advice. Weber Motors are definitely not helping.

dgiturbo

This reads like the control circuits or wiring circuits used for the block heater is overloading the switching circuit for the cooling fan. An electrical engineer would have to redesign this. Doubt software will do it.

GLKKa2H

I read “Developed a problem” as the heater created no faults at purchase – and some time afterwards.

Although not being familiar with the commercial power in Canada with regard to voltage (115 Volts?) or ground vs. high tension, I take the chance of reponding anyway.

Based on the interpretation of “developed” and the components changed, I would say this could point towards the heater as such, and a possible “ground leak” e.g. a (partial) leak of the commercial voltage to the block of the engine.

In general, such a leak can create peculiarities in any electronic/electrical system. In your case could such a leak create induced power thru the engine block, thus hitting the temp. sensor (or any other component) causing a capacitive charge which takes time to discharge (“- off but starts again with any restart for about the next 24hours.”). Dependant on the principle of the MB temp. sensor, could this fool the sensing.

Another possibility is that a “ground leak” could cause the coolant to change chemically. Not very likely in your case though, as it’s a “unpurified” mixture. I have experienced a faulty electrical circuit where sparks splitted purified water into molecules, triggering fault sensing circuitry. It took hours before the water “regenerated” again.

So, ask Weber Motors if they have performed a conductivity test of the heater – to be infinite ground/heater element. As well should the yellow engine malfunction indicator be represented by a thrown code which you should ask for.

WC Owner

Did you solve this problem? I just installed a cord for block heater on 2011 GLK and have the same problem

DWP147

re: Fan running at Max after plugging in block heater
I'm also wondering if anyone has a solution, this same problem with the fan running at max after plugging in the block heater happens a couple times a year. Of course, I can't duplicate the problem when I take it in to the dealer. The dealer here in Calgary, Alberta says that they've never heard of this problem before, and can't fix it if they can't duplicate it.

2010 GLK350

bop11

GLKKA2H may have a good idea but I would think that a ground problem would also cause other systems to act weird. I don't know why MB would connect the heater into their circuitry. I would think a block heater would just plug into line voltage with a built in thermostat as is done with aftermarket units. Your particular heater may be getting too hot and the hot coolant is trapped at the thermostat telling the fan thermo sensor the engine is hot and needs the fan. Sounds like the coolant may go above a "High-High" ( remember these are sensors not switches) degree which would set a flag in the software to turn on the fan with each engine start. After several start stop cycles, where the coolant is not above this limit, the flag is reset, similar to a lose gas cap reset. It is funny that the memory does not record this flag even after the light goes out. Try to get the OBD read when the warning lamp is on so the flag is active. This "High-High" setting may have come from tests in a very hot dessert climate and not apparent to service people in a more moderate climate where we would never see it.
With an OBD scanner, you could probably read the temperature sensor just before start up after using the heater to see how hot the sensor thinks the coolant is.
I am not sure even MB know what is totally in the code since it is evolution of program and not new every model.
Good luck