Thanks for the Andrew, I am thinking that the wiring looks the same as an ML I have on my books, there is an E class as well but cannot remember if the wiring is the same?

Anyway.....woo hoo the fan has arrived! I will pull the rad at the weekend and do a trial fit.

Regards

Dave

Okydoke, today I connected the fan I acquired from a C class to an ML to test it. The plug was identical however the wiring colour on one lead was different. The C class I have had the heavy red and Brown cables, a thin black and white and a green and blue, on the ML the wires were the same with the exception of the green and blue, on the ML the cable was yellow and blue. Keeping in mind this is a customers car and I did check with him to see if it was ok to use it as a guinea pig.

So before doing anything we tested his fan, the engine was fairly warm, after starting his engine the fan did not come on for three minutes or so, when it cut in it was very quiet, the temperature did not rise and we gave up after ten minutes or so. Switching on the AC the fan speeded up but I would not say it was full speed, The AC was cold, the fan slowed once or twice and then picked up again, I am unsure if the AC ecu controls this via condenser temperature sensor or trinary switch as per my car.

So we pulled the plug and with the colour difference in mind plugged it into my C class fan, started the engine and the fan started up in less than a minute, about two minutes in and the fan gained some speed, obviously the ECU had detected the engine is not being cooled correctly, switching on the AC the fan again stepped up the revolutions. We shut down the engine as we did not want to risk overheating it.

We then put the plug back where it belongs, the ML fan came on within about ten seconds and it was clearly spinning faster than it was at the beginning of the test however, in less than a minute though it slowed down again to become almost silent, AC response was the same as before.

Observations:

Cable colour difference, unsure if this was the trigger wire or what?

The ML fan is bigger both in diameter and blade count.

The C class fan was noisier but it was being held near the front corner of the ML to reach the plug, there was no obstruction to airflow so that may be the reason?

The ML fan is 850 watts.

I forgot to measure the centre mounting bolts, but there are four the same as the C class, possible to swap motors in the future?

So, whilst my fan did not spool up to full speed as the ecu decided it was not needed, I am for the moment calling the fan good, and this weekend will see the radiator pulled out and see how well the fan fits.

Regards

Dave

You will not have any need to change the fan motor. When these things spin up to high speed they move a disturbing amount of air.

With the hood closed on my 65 and the cooling fan on high I opened the driver's door and could feel air blowing out from under the car.

Hi feets, I did read your earlier observations and this contributed to my choice of fan. I was not thinking of the amount of air being moved, more about longevity of the fan motor.

I had actually thought about just leaving as is in fact, it may be possible that the 850 watt motor may spin the same speed, and the wattage increase made to cope with the extra amount of air the larger fan will be moving, so only extra life expectancy.

It also crossed my mind that if the 850 watt unit did spin faster, the pitch of the 600 watt fan blades may not be suited to the extra speed, much in the same way that a boat propeller can be optimised for 'X'revolutions.

Given the abundance of these fans, and assuming it works ok I may fit and leave as is.

Regards

Dave

Update.

Using the PWM from @hooziewhatsit I have now been able to test the fan fully, and as per @feets comments it really does move a lot of air. Testing in the kitchen (as you do), anything not nailed down on the work surface started migrating towards the fan suction side!

I am working on getting a small circuit made up to allow the PWM to control my presently installed dashboard indicators to work. I have copied a diagram kindly supplied on an electronics forum however, unfortunately it does not work, clearly my soldering technique needs some work!

Glad I came across this forum purely by chance, so hats off to @feets and @hooziewhatsit and other members who have contributed.

Regards

Dave

Now you will need a better than stock charging system. I have the same setup as you and it has been working great for 5 Year’s now.

Thanks for the update!

It's good to see everything is working so far.

The first time you spin one of those fans up on high speed it's kinda disturbing. They move some serious air.

I already had the well known Lincoln MK8 fan for the last couple of years, so I addressed the issue with a 150 amp alternator, so all good there.

"Kinda disturbing" is one way to put it!

I actually posted up on my regular 4x4 forum that I thought it was going to suck the pattern out of the work top!

Now I just need to sort the LED circuit out, as mentioned earlier, my soldering skills really suck.

Thanks again guys.

Regards

Dave

OK a little update, apart from some teething problems I can now confirm that Dave's PWM controller works great with my dashboard fan speed indicators.

Between Dave and Alec a member of the electronics forum, they have given me exactly what I want, my dashboard not even needing to be removed to complete everything.

It will be another few weeks before all is installed permanently in the Land Cruiser and proper testing commences. The real test though will be climbing Spain's mountainous desert areas fully loaded in August, temperatures are normally circa 50°C (122°F) during this period, a test indeed!

Thanks all round

Regards

Dave

Good Luck

Hi all, presently just an observation.

Keeping in mind my fan install is in a Land Cruiser heavily loaded and used off road often in 50°C heat. During fan testing (and I test anything going on my 80 very thoroughly), I notice the main fan cables that are direct to the battery get quite warm when the fan is flat out for more than around five minutes.

The power being pulled during this time is circa 45 amps, this ties in with pretty much what is expected with a 600 watt motor, so worn bearings or other problems with fan can be discounted. The plug and cabling is as per supplied via Dave (Hooziewhatsit) with the PWM controller, I gather this is how Mercedes supply it. I did mention the cabling was not particularly heavy considering the amperage and Dave confirmed it is as per Mercedes, so happy with that.

Now I am thinking it would be rare for one of these fans to be run at full speed for any length of time, given their output and used in a typical on road use scenario so the cables may never be 'pushed' however, it may happen when I am on a long hot climb fully loaded, so thinking worse case scenario here.

When the fan arrived it came with a pigtail, I had kept this and noted the battery wires were substantially heavier. My first thought is the thinner cabling that came with the new plug may be for the 400 watt fan which is used on smaller engines? So, the plan is change out the plug with one that has heavier cables, purchasing the plug is easy enough but they do not come with any terminals? At the moment I am struggling to get my head around that, anyone purchased a plug recently that came with terminals?

The fan and PWM controller continue to work faultlessly, I have made one or two mods, one being tested as we 'speak', this is the post shutdown timer, and this allows the PWM controller to keep the fan on despite the ignition being off. The small circuit that changes the PWM signal to a steady state for my dashboard LED is also good.

So, just a change of battery cable methinks......if I can get the terminals?

Regards

Dave

I know when I hooked mine up I had to buy the terminals separately. It's been over 5 years since I did it so I can't give you any details. Feets might be able to help you since he works at a Mercedes dealer.

Thanks for that, I can see the plugs aplenty for sale but none have terminals, I gatherered Mercedes supply the cable and terminal already assembled so out of luck there. As you purchased them separate, then I may be in with a chance.

I do have the possibility of crimping heavy cable onto the old pigtail, but prefer not too, wishing to keep connections to a minimum.

Thanks again, off to bed so will check in again tomorrow.

Regards

Dave

I get the cables and the housing direct from MB. I'm not actually sure if there's a larger gauge cable available that will fit in the pin housing or not.

I've looked quite a bit in the past for loose pins that I can crimp myself, but was never able to find the same ones.

if 5 min is your judge, I don't think it is an issue.
the wires do come seperatly, and maybe feets will join in and look them up.

I have the controler on mine set a bit low. so I know it runs flat out the entier time the car is warm enough to fire it up.
I also had without a controler where it just ran flat out the whole time the car is on.
never had an issue.
now I probably haven't kept the car running more than an hour or 2 at a time as I haven't taken it cross country or anything.

I also compared the wiring to an r-class and it seemed to be the same.

Hi Dave, I do recall you said they came from MB, so looking for the reason that the OE install had heavier cable.

Regards

Dave

Sorry I was not completely clear in my post, I have not run it much past five minutes preferring to not tempt fate as I was unsure if the cabling will get hotter.

I am going out today to run the fan flat out by using the excellent disconnected sensor facility the PWM has.

If 'feets' has anything to add it would be appreciated.

Regards

Dave

Well the only news I have is bad.

15 minutes had main cables hot and smelling, hot enough to start melting the insulation!

The 50 amp resettable breaker did not trip, if there was a fault with the fan I am sure it would have tripped.

I am sure the clue is in the cable dimensions, unsure if I am able to upload photos with such a low post count?

About to find out, dirty fingers clearly shows my retirement plans went adrift.

Regards

Dave

The red wire is from the OE plug, it has an earth in Brown of the same dimensions.

This test was @ 22.0°C outside temperature, power being drawn after 15 mins was 45 amps as near as dammit.

When off fan spins easily by finger, no noise from bearings, thermo sensor on fan centre shows no difference to ambient temperature. The same on the heat sink where the fan connects.

Two fully charged 12v marine batteries in parallel, no appreciable drop in voltage, 13.3 standing overnight, 12.8 during test.

I plugged the OE connector in and lengthened the cables to reach the CB, run for a further 15 mins, no heating of cables.

I plan to continue looking for the correct terminals so I can wire in heavier gauge cable, in the meantime I hope 'feets can find something On the MB computer?

Regards

Dave