Replacing W210 aux fans with upgraded units? - Page 2 - PeachParts Mercedes-Benz Forum

Zulfiqar · #16 06-01-2015, 03:56 PM

if your car's fan clutch is original from the assembly line, it might never work even when hot, it bleeds out its silicone oil over time and fails to operate.

however.

it should roar when you cold start the engine in the morning, that roar happens because the silicone oil pools in one corner of the clutch effectively engaging it, it should go quiet after a few seconds - new one roars for a good 30 seconds when cold started.

m1tch · #17 06-01-2015, 04:02 PM

Quote:

Originally Posted by Zulfiqar

if your car's fan clutch is original from the assembly line, it might never work even when hot, it bleeds out its silicone oil over time and fails to operate.

however.

it should roar when you cold start the engine in the morning, that roar happens because the silicone oil pools in one corner of the clutch effectively engaging it, it should go quiet after a few seconds - new one roars for a good 30 seconds when cold started.

Hmm I have a feeling that mine is pretty much past it then lol - tempted to just go for the fully upgraded route of replacing it with an electric fan, would take the load off the engine as well.

tjts1 · #18 06-01-2015, 04:49 PM

Quote:

Originally Posted by Zulfiqar

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

Yeah, unfortunately that one doesn't fit in front of an om606.

tjts1 · #19 06-01-2015, 04:58 PM

Quote:

Originally Posted by m1tch

Hmm I have a feeling that mine is pretty much past it then lol - tempted to just go for the fully upgraded route of replacing it with an electric fan, would take the load off the engine as well.

I would look at the dual pusher fans from a late w124 or w140 with an appropriate temp switch and relay. That should be more than enough cooling for your om606 and it'll leave more room at the front of the engine.

Fan switch info.

Jeremy5848 · #20 06-01-2015, 06:43 PM

I have not noticed any cooling problems with either the 124/606 or the 210/606 but the mild climate here in NorCal may have something to do with it. The W210 came (at 249,000 miles) with only one electric fan working; it took me awhile (my first W210) to realize that there was only one electric motor. As others have observed, the little belt breaks / wears / comes off. My W210 fans have worked well since I installed a new belt.

The mechanical fan/clutch is another matter; clutches tend to fail gradually so that it isn't immediately noticeable until you need extra cooling and it isn't there. I have replaced both clutches just to be on the safe side, since I had no idea how old they were.

In the W124, I can now see (with a newly-installed monitor LED) how often the electric fans come on in low-speed mode. I'm surprised how often they operate, even when there is airflow from motion. I had thought the electric fans came on mostly when the car was stopped in traffic. T'ain't so, McGee!

Jeremy

m1tch · #21 06-02-2015, 02:52 AM

Quote:

Originally Posted by tjts1

I would look at the dual pusher fans from a late w124 or w140 with an appropriate temp switch and relay. That should be more than enough cooling for your om606 and it'll leave more room at the front of the engine.

Fan switch info.

Thanks for that, I will be looking into the cooling system overall as it looks like my thermostat is stuck open - on cruise it was at around 70c. Need to find out which thermostat I have as I know the previous ones were all 1 piece with the neck vs just the thermostat. Oddly the thermostat housing looks brand new on my car - will check to see what version it is.

I am also looking to upgrade the radiator anyway, I don't really trust old plastic end cap radiators as they get brittle over time. Plan to add in a much thicker 'race' radiator which would mean electric fans only.

m1tch · #22 06-07-2015, 03:51 PM

Just checked my aux fans using the test procedure, it doesn't work on mine, I have checked the units and I have found the following:

A wiring block connector just after the OEM plugs
A long negative cable running to one of the earthing points in the nearside of the engine bay
Nothing connected to the positive side in the wiring block

It seems that someone has tried to fix the issue but has simply given up and cut the control box out.

I have however tested the aux fans by running a positive feed from the positive power post in the engine bay to the positive side of the fans - they work really well so I think I will simply wire in a manual switch to allow me to run them when needing to.

Zulfiqar · #23 06-07-2015, 05:07 PM

Quote:

Originally Posted by m1tch

Just checked my aux fans using the test procedure, it doesn't work on mine, I have checked the units and I have found the following:

A wiring block connector just after the OEM plugs
A long negative cable running to one of the earthing points in the nearside of the engine bay
Nothing connected to the positive side in the wiring block

It seems that someone has tried to fix the issue but has simply given up and cut the control box out.

I have however tested the aux fans by running a positive feed from the positive power post in the engine bay to the positive side of the fans - they work really well so I think I will simply wire in a manual switch to allow me to run them when needing to.

I believe someone tried to fix it but had wrong approach, there is a PWM contoller housed in the fuse box in the early w210s that accelerates and decelerates the fans, if you test the positive side with a test lamp you should see it blink rapidly at startup and then go into its cycling rythm. When that little control relay fails your fans dont work.

The later W210s have that fan control box under headlamp.

m1tch · #24 06-08-2015, 02:52 AM

Quote:

Originally Posted by Zulfiqar

I believe someone tried to fix it but had wrong approach, there is a PWM contoller housed in the fuse box in the early w210s that accelerates and decelerates the fans, if you test the positive side with a test lamp you should see it blink rapidly at startup and then go into its cycling rythm. When that little control relay fails your fans dont work.

The later W210s have that fan control box under headlamp.

Yeah, I don't actually know what the previous owner was trying to do, I am not planning on reinstating the OEM setup but rather use the aux fans as a manual override for additional cooling. I have found that my viscous fan is fine and seems to engage correctly, although I need to get the thermostat replaced first!

I was planning on simply swapping these out for an aftermarket single fan, but after the fan test yesterday I am happy to keep the aux fans and simply override them - they do push a lot of air when on 100%.

Kajtek1 · #25 06-08-2015, 09:26 PM

This cooling system is design for towing 5000 lb trailers on Sahara desert, or high into the Alps, so if your engine shoots to 100C, you cooling system was neglected.
Wife E300dt needed new radiator soon after purchase, so I bought Behr and was religious about maintaining Mercedes coolant in it.
Year later water pump broke and in the process of changing it, I discover that visco clutch is not doing anything, so I did not put it back.
Waiting for new clutch I was driving the car observing the temperatures and at cruising it would stay at 78C even with 101F outside.
So when new clutch arrived, I put blades on it, but never installed it.
We drove the car like that for about 5 years and the hardest test was idling at freeway accident with 114F outside.
In critical moments the engine would go to 95C, when electric fans would kick on high and the engine started to cool down.
The new clutch sold with the car sitting in the trunk.

m1tch · #26 06-09-2015, 02:56 AM

Quote:

Originally Posted by Kajtek1

This cooling system is design for towing 5000 lb trailers on Sahara desert, or high into the Alps, so if your engine shoots to 100C, you cooling system was neglected.
Wife E300dt needed new radiator soon after purchase, so I bought Behr and was religious about maintaining Mercedes coolant in it.
Year later water pump broke and in the process of changing it, I discover that visco clutch is not doing anything, so I did not put it back.
Waiting for new clutch I was driving the car observing the temperatures and at cruising it would stay at 78C even with 101F outside.
So when new clutch arrived, I put blades on it, but never installed it.
We drove the car like that for about 5 years and the hardest test was idling at freeway accident with 114F outside.
In critical moments the engine would go to 95C, when electric fans would kick on high and the engine started to cool down.
The new clutch sold with the car sitting in the trunk.

I think the highest mine has got to was around 93C which was sitting in a queue of traffic, would have been just the viscous fan as the aux fans seem to have been disconnected. I think I might get one of those universal thermostat kits and connect it to the aux fans at the front.

I need to replace the thermostat in the car anyway so I might measure up for a larger race radiator although the OEM one seems to be in good condition.