aux. fan, mods and testing - PeachParts Mercedes-Benz Forum

coachgeo · #1 06-29-2003, 06:24 PM

This idea just struck me as I was reading another thread about the aux. coolers in MB 300's. My rig does not have an aux. cooler. For longevity of my 617 it might be a nice addition to have since my rig runs around 200F and on a hot day it will climb up to around 230F when plugging along up long hills on the highway.

Anyway, I can pull the aux. fan off a junker 300 MB sedan at a local yard. Is it a in front of radiator aux. fan or an in back of the radiator by the engine's fan. I don't recall off the top of my head. If it's an in front of radiator aux. fan then I have room for that on my beast so it would just mean I would have to build brackets to install it on the Unimog.

What all would you suggest I pull out of the junker for this?

How would I go about testing the parts pulled off the junker?

What temp sensor does this fan work off of? Same sensor as engine temp. gauge sensor?

When it comes to wiring the sensor up how would I swap it onto my 617 powered rig that does not have an aux fan?

I could hard wire it too I guess and just turn it on with a toggle switch. Would I need a solinoid for this? in fact... think even if I have a sensor I will want to wire in a togle so I can turn it or and alos off. Need an off for durring deep water forging. I've heard of the blades bending and slicing radiators when forging deep water.

Thanx in advance
George

The Warden · #2 06-29-2003, 06:45 PM

The electric aux fan on my car is in front of the radiator.

In all honesty, though, it might be better to buy an aftermarket fan, and then get the biggest one that you can fit in there. leathermang posted a site where you could get them not too long ago; I don't remember exactly what the URL is, though.

I think that the fan runs off of a sensor on the engine to sense engine temp, but I don't know where this is if that's true, and it's also suposed to come on whenever the a/c compressor is engaged.

I'd love to get mine working, but I need a new brush housing...the front bearing died on mine, and the brushes melted the plastic housing while trying to turn it.

coachgeo · #3 06-29-2003, 06:52 PM

Quote:

Originally posted by The Warden
The electric aux fan on my car is in front of the radiator.

In all honesty, though, it might be better to buy an aftermarket ....

Thanx... but since Im on a tight budget; no job "yet" and no unemployment, I'm better off going the junkyard route. I was going to go pull some other stuff off of that MB anyway so thats why I was thinking grab the aux. fan and parts while I'm at it. Particularly any switches etc that works off the MB 617 engine sensors cause then I'll have matching swithches and sensors.

JimSmith · #4 06-30-2003, 12:26 AM

coachgeo,

I think if you submerge one of these fans you may ruin it as I do not think they have sealed bearings and they use brushes. Water is not recommended for soaking either of them, especially when in use. You may try one though to check out the set up and then make it easy to remove when you go into deep enough water, if that is even practical (I imagine sometimes you may not have a lot of notice about the depth of water). In the end when you find the time and money you could substitute something a little more suited to this kind of abuse.

When you harvest one from a boneyard, follow the power line and take as much of what is connected to it as possible. This should lead you to the sensor as well. I am sure your car has something plugged into the sensor spot, which is either on the head or on the thermostat housing. You may want to take the thermostat housing from the donor car if that is where the sensor is plugged in, as the one on your car may not have all the necessary ports for the extra sensor.

Good luck, Jim

coachgeo · #5 06-30-2003, 12:39 AM

Quote:

Originally posted by JimSmith
coachgeo,

I...
When you harvest one from a boneyard, ....
Good luck, Jim

ahhhhh...... good suggestions... will do

thanks.

leathermang · #6 06-30-2003, 08:15 AM

If I needed air flow and had a big vehicle with room I would find a squirrel cage fan, make my own enclosed radiator and mount the fan high with a four inch tube from Home Depot going to the radiator. The type of aux fan on cars is of that type because of limited amount of room and need to not block ram air . You are watchin the temps... just fuse it and put an on/off switch for you to control.... a temp activated switch is just one more thing to go wrong when you least want it to.

leathermang · #7 06-30-2003, 12:13 PM

I thought you were wanting an aux oil cooler with associated fan.... squirell cage fans are what is used inside the passenger compartment in the air conditioning system... so should be readily available.... and have enough force to allow remote positioning and ducting to what needs the air...

HUM,,, this posted out of order...

rk300d · #8 06-30-2003, 12:41 PM

my aux fan is sounding a little dry.....is there any way to lube it?

cscmc1 · #9 06-30-2003, 12:52 PM

Someone rigged up what looks to be an aftermarket electric aux fan in front of the radiator on my 220D parts car. It has a sensor for coolant temp and a relay (presumably to turn the fan off and on). I have never tested this thing, but it's yours for the cost of shipping if you want it. I hate to throw any more away than I have to on the pars car. If you'd like, I can fiddle with it and see if 12 volts gets it running, if it's quiet, etc...

Chris
cscmc1@eiu.edu

coachgeo · #10 06-30-2003, 01:05 PM

Quote:

Originally posted by leathermang
If I needed air flow and had a big vehicle with room I would find a squirrel cage fan, make my own enclosed radiator and mount the fan high with a four inch tube from Home Depot going to the radiator. The type of aux fan on cars is of that type because of limited amount of room and need to not block ram air . You are watchin the temps... just fuse it and put an on/off switch for you to control.... a temp activated switch is just one more thing to go wrong when you least want it to.

Thanks,

are you describing a seperate cooler plumbed into things? I dont know the term "squirrel cage fan" I'm assuming you mean the type whose fan is a drum with fins.

Space is a premium. To fit the 617 motor into the Unimog special adapters were made to tilt it 13 degrees to one side so it could be shoe horned in there.

If I do a typical infront of radiator aux. fan modification using MB or other parts, I will turn it off for water crossings. This is a very common mod. in the off-road world so history seems to show they do ok (some better than others) going thru water, just not turned on in the process.

coachgeo · #11 07-01-2003, 05:07 PM

Quote:

Originally posted by cscmc1@eiu.edu
.... but it's yours for the cost of shipping if you want it.
Chris

Thanks man... wow..... this did really get posted in an out of order way.. wiered.

Anyway I pulled the fan from the 300D at the boneyard. Walk out to my Mog and noooo way baby. notta going to fit... no room.

Leathermang, I am now thinking same as you. There is a little room infront or inback of the oil cooler where there is not either at the radiator. Only thing that concerns me with the ducting idea is that when the fan is not on.. the duct blocks the flow of air. hmm... unless its a puller fan? wonder if AC fans are pullers or pushers.. and wonder if one could just reverse the polarity and run it backward? I donnna know? Thanks for the idea's though. I'll keep my eyes open for bits and pieces.

leathermang · #12 07-01-2003, 07:07 PM

Even if you could reverse direction on a squirell cage fan that would not be a good thing to do... all the fins are designed to throw air OUT....and suck into the hub... that would NOT be good to try....
Even if it is a puller it would completely mess up your ram air effect.
Why do you need ram air ? Why not plan on running the fan all the time you run the truck ?
By ' ac fans' if you are talking squirrel cage.. they pull to their inside and blow out the side.
When dealing with fans be advised that you can not simply reverse the fan blade on the fan shaft. Still moves air the same direction... LOL.. just in case you were thinking of trying it....

coachgeo · #13 07-01-2003, 10:00 PM

Quote:

Originally posted by leathermang
... By ' ac fans' if you are talking squirrel cage.. they pull to their inside and blow out the side. ..

Thanks Leathermang

So the squirl cagers pull toward the inside and throw to the outside 360 degree... or just off to the left or right or? I assume 360 degree and thus why they use them in AC duct.

leathermang · #14 07-01-2003, 11:41 PM

There output is usually directed towards a few degrees of the circumference... but for the amp motor and the space they put out much more air than a regular fan blade... that is why the cooling fan on an old VW air cooled engine is that type... much more force also... of course the classic example is the hand powered blacksmith blower... strong enough to deal with several inches of coal... something a regular fan could not do... ( of the same size )...

coachgeo · #15 07-02-2003, 12:14 AM

Quote:

Originally posted by leathermang
There output is usually directed towards a few degrees of the circumference... but for the amp motor and the space they put out much more air than a regular fan blade... that is why the cooling fan on an old VW air cooled engine is that type... much more force also... of course the classic example is the hand powered blacksmith blower... strong enough to deal with several inches of coal... something a regular fan could not do... ( of the same size )...

K..... well guess since its little more complicated then just popping in an ax. fan then this project gets pushed back for another time. To bad.. would be nice little piece of security to have for the trip to Fl. Course then agian this thing has been across the desert; at a slower pace Im sure though, with out one so I guess it should be fine