Replacing W210 aux fans with upgraded units? - PeachParts Mercedes-Benz Forum

m1tch · #1 06-01-2015, 08:01 AM

Hi all,

After waiting in line for a couple of drag runs over the weekend I noticed that my engine temps were climbing up a bit and felt that it would be better to upgrade the fans.

Usually the coolant temperature when on cruise sits at around 60c, it does rise up to around 85c when accelerating or in slower traffic conditions around town but it has been up around 93-94c.

I know that there is the large viscous fan passively cooling the engine and I believe starts to work at around 90c when the viscous clutch engages, however I am wanting to have something a bit more reliable.

I am therefore thinking about either swapping out the front aux fans or indeed adding a manual override switch to allow them to be turned on independant of the relay. I have tried to test the fans by using the test procedure of pressing both the Auto buttons in however I have no joy in them working.

I would therefore assume that there is an issue with the pusher fans on the front of the car so I am tempted to just bypass them manually or get them to function when the car gets over 90c. I am aware that they aren't the best design, however should push some air through the system when active.

Has anyone retrofitted anything or modified their setup at all?

Stretch · #2 06-01-2015, 08:42 AM

60 degrees doesn't sound right - I don't know for sure for your engine but usually between 85 and about 95 is normal for a Mercedes engine in my experience.

As for fans and your usage I think manual override would be ideal. Have a look on the Kenlowe web page for some ideas. I did buy a kenlowe fan for my 300D but never got round to fitting it...

shertex · #3 06-01-2015, 08:46 AM

Yeah, 60 isn't right. Both of my 606.962's cruise at 80 or so.

tjts1 · #4 06-01-2015, 09:14 AM

The w210 aux fans are pathetic. There only one motor driving both fans and they move very little air through the radiator compared to real pusher fans. What you can do while waiting in line is press and hold the 2 AUTO buttons on the CCU for 10 sec. That will switch on the aux fans manually. Also make sure when you spin one fan by hand the other one also turns. There's a belt in between them

shertex · #5 06-01-2015, 09:45 AM

Quote:

Originally Posted by tjts1

The w210 aux fans are pathetic. There only one motor driving both fans and they move very little air through the radiator compared to real pusher fans. What you can do while waiting in line is press and hold the 2 AUTO buttons on the CCU for 10 sec. That will switch on the aux fans manually. Also make sure when you spin one fan by hand the other one also turns. There's a belt in between them

I didn't know that. Tried it on the 99 and only the driver's side fan spins. So I suppose the belt is broken?

tjts1 · #6 06-01-2015, 09:56 AM

Quote:

Originally Posted by shertex

I didn't know that. Tried it on the 99 and only the driver's side fan spins. So I suppose the belt is broken?

Yes. The driver's side contains the motor in its hub. The passenger side hub is much smaller without a motor. The short belt between the fans is easy to replace.
https://youtu.be/9loVJApsuFI
I tried to replace my pax side fan with a second motor driven fan but the mounting holes are positioned so left and right are not interchangable.

shertex · #7 06-01-2015, 10:22 AM

Quote:

Originally Posted by tjts1

Yes. The driver's side contains the motor in its hub. The passenger side hub is much smaller without a motor. The short belt between the fans is easy to replace.

Although I wonder, especially in New England, if it matters whether the second fan spins.

tjts1 · #8 06-01-2015, 10:26 AM

Quote:

Originally Posted by shertex

Although I wonder, especially in New England, if it matters whether the second fan spins.

HAHA well if the car survived this long... I suspect it'll make the AC a bit more effective. Even when functioning properly the W210 aux fans are pathetic when compared to the late W124 or W201 dual electric aux fan setup. Just another example of MB's penny pinching era. A belt is cheaper than a second electric motor.

Zulfiqar · #9 06-01-2015, 11:27 AM

Quote:

Originally Posted by tjts1

HAHA well if the car survived this long... I suspect it'll make the AC a bit more effective. Even when functioning properly the W210 aux fans are pathetic when compared to the late W124 or W201 dual electric aux fan setup. Just another example of MB's penny pinching era. A belt is cheaper than a second electric motor.

they removed the aux fans completely from the last W210s, just one big electric fan on the radiator which is PWM.

Zulfiqar · #10 06-01-2015, 11:31 AM

Quote:

Originally Posted by m1tch

Hi all,

After waiting in line for a couple of drag runs over the weekend I noticed that my engine temps were climbing up a bit and felt that it would be better to upgrade the fans.

Usually the coolant temperature when on cruise sits at around 60c, it does rise up to around 85c when accelerating or in slower traffic conditions around town but it has been up around 93-94c.

I know that there is the large viscous fan passively cooling the engine and I believe starts to work at around 90c when the viscous clutch engages, however I am wanting to have something a bit more reliable.

I am therefore thinking about either swapping out the front aux fans or indeed adding a manual override switch to allow them to be turned on independant of the relay. I have tried to test the fans by using the test procedure of pressing both the Auto buttons in however I have no joy in them working.

I would therefore assume that there is an issue with the pusher fans on the front of the car so I am tempted to just bypass them manually or get them to function when the car gets over 90c. I am aware that they aren't the best design, however should push some air through the system when active.

Has anyone retrofitted anything or modified their setup at all?

Your thermostat is either missing or is jammed in the open position. In both cases you will see an overcooled engine at cruise and an overheated engine at load (like pulling a drag)

the thermostat blocks a bypass port to force all coolant to go into the radiator for maximum engine cooling, with the bypass open coolant takes the path of least resistance and goes back into the block.

The gauges on MB are showing you nearly actual temperature, while idling at a light or backed up traffic it will creep up to 99 or even 100C which is the 3/4 mark on the gauge - its completely normal, most other cars have a buffered gauge which are downright silly, e.g. my toyota has a buffered gauge, it stays put at a smidge below half point at any temperature between 82-99C.

tjts1 · #11 06-01-2015, 11:41 AM

100c on an OM606 is never normal. Maybe when ambient temp is well over 40c while sitting in traffic but thats not happening in the UK. He likely has a weak viscous clutch fan.

vstech · #12 06-01-2015, 12:03 PM

Quote:

Originally Posted by tjts1

100c on an OM606 is never normal. Maybe when ambient temp is well over 40c while sitting in traffic but thats not happening in the UK. He likely has a weak viscous clutch fan.

I know he has a euro spec, I did not know he was IN the UK...

100C is indeed normal on a diesel MB... it takes a lot of load to get there, or a lot of outside heat... or a lot of dirt in the radiator... but it will show 100C and still be operating normally.

everything clean and working properly though, the car should not see 100C

m1tch · #13 06-01-2015, 02:23 PM

Quote:

Originally Posted by vstech

I know he has a euro spec, I did not know he was IN the UK...

100C is indeed normal on a diesel MB... it takes a lot of load to get there, or a lot of outside heat... or a lot of dirt in the radiator... but it will show 100C and still be operating normally.

everything clean and working properly though, the car should not see 100C

Yeah I am in the UK - its why I have an OM606.962 in a wagon body as standard

I have a feeling that the thermostat might be sticking every now and then - sometimes it does sit at around 85 but I have seen it run quite cool every now and then when on cruise. I guess I am lucky that it seems to be sticking open rather than closed!

I will look into swapping out the fans for something else, I have a feeling the control box might have had it as I am having no joy with the testing procedure - I am thinking that a single large high performance fan attached running on a thermostatically controlled switch should do the job. I will have a look for a basic kit and perhaps also look at getting a new thermostat!

I am also looking to fit a Davis Craig electric water pump to run along side the additional fan - as well as looking to fit an uprated metal race radiator but that is a while off.

Zulfiqar · #14 06-01-2015, 03:33 PM

on my 606 engine, it will shoot for the 100C mark without a problem even in the winter of Houston, which is the summer for you in UK.

mine is the NA engine - so it has an 85 degree thermostat in it, it maintains a 90C temperature at all times.

The fan clutch kicks in at quite high temperature, usually near 100C sitting idle, the clutch soaking up the heat. It gives a loud audible roar to let you know its working.

m1tch · #15 06-01-2015, 03:51 PM

Quote:

Originally Posted by Zulfiqar

on my 606 engine, it will shoot for the 100C mark without a problem even in the winter of Houston, which is the summer for you in UK.

mine is the NA engine - so it has an 85 degree thermostat in it, it maintains a 90C temperature at all times.

The fan clutch kicks in at quite high temperature, usually near 100C sitting idle, the clutch soaking up the heat. It gives a loud audible roar to let you know its working.

I haven't heard the main fan kick in (viscous or electrical) so I am guessing that my thermostat is running the engine a bit too cool for anything to start working. I did notice on the gauge that the redline is at 120C with 100C being around 3/4 of max.

FYI for anyone else with the W210, there is a hidden menu within the AC unit, press the 'Rest' button for around 6 seconds, it will come up with a code on the left and right, press the left auto button to scroll round to number 6, that is your coolant temperature in degrees C as a digital read out.