Auxiliary fans questions/issues

[French02chris]

Hello.
One of my auxiliary fans hasn't been working for 2-3 years now... It's seized. (going to be replaced in the coming week, finally)

My question is : would this failed fan cause the other auxiliary fan not to kick in when a/c is turned on???

The only way for me to have the working fan kicking in is to "jump start" it with my foot (making the fan rotate when spinning it with my foot... If that makes sense to you)

High speed fan seems to be fine... Never needed it as the engine temperature never goes high enough (but I tested it by unplugging the coolant temp sensor when engine is at normal temp)

Thank you

 

[emerydc8]

I would look at the power output after it's gone through the low-speed (step-down) resister behind the driver's headlight and going to the fans. It's possible that the resistor or wiring could be corroded so much that it's just not driving the remaining low fan unless you get it started with your foot. Fans have been known to fail but if you're saying that both fans work okay on high-speed, then it sounds like maybe one fan could have failed but there is also not enough power getting to the low-speed fans.

 

[French02chris]

Only one fan is working.. The other is seized

 

[gsxr]

I agree with Jon. Check the wiring at the resistor behind the driver headlight.

Also, if you are not replacing both fans, inspect the kickstart-fan closely. And, if not buying OE fans, read the few posts starting here about aftermarket fans.

 

[gsxr]

Forgot about this... here's the HOW-TO link:

HOW-TO: Replacing the twin electric auxiliary cooling fans | "HOW-TO" Tutorial Articles

I happened to notice that one of the electric auxiliary cooling fans on my wife's 500E was intermittently not working. The one fan would be whirring away, but the other was silent. It would jump to life if I whacked it though. I figured the brushes were worn in the motor, and that it needed...

www.500eboard.co

 

[French02chris]

I agree with Jon. Check the wiring at the resistor behind the driver headlight.

Also, if you are not replacing both fans, inspect the kickstart-fan closely. And, if not buying OE fans, read the few posts starting here about aftermarket fans.

excuse my ignorance, but what should I been looking for when I inspect the kickstart fan?
However, I will replace both fans

 

[gsxr]

excuse my ignorance, but what should I been looking for when I inspect the kickstart fan?
However, I will replace both fans

See if the brushes or commutator have visible/excessive wear (unlikely), make sure the motor spins freely and smoothly, etc. I'd also try applying +12v directly to verify it spins up without requiring a kickstart. This job is not fun, you won't want to repeat it.

 

[emerydc8]

I used @gsxr's above-post on fan replacement and it wasn't a bad job. The one thing to note--and I think he also points out--is to make sure the new fans spin in the right direction. IIRC I had to swap the plug around to do this. Also, even just one weak low-speed fan will result in poor air conditioning. I chased and replaced everything in my a/c system and I couldn't figure out why the high-side pressure would increase until it hit the cutout and then ride on the pressure cutout. I thought there was a clog somewhere in the system. Turns out the fan (only one) was not cooling the condenser enough. Although the fan was still turning, it was weak and I could grab it and easily slow it down to a stop with my hand.

 

[French02chris]

The issue was the red switch...

New auxiliary fans working again..

However I have a doubt about the viscous fan : is it supposed to spin clockwise (when you look at it from the front or counterclockwise?????)

Thanks again

 

[gsxr]

However I have a doubt about the viscous fan : is it supposed to spin clockwise (when you look at it from the front or counterclockwise?????)

The viscous fan can only spin in the correct direction because it's driven by the pulley system. This assumes the serpentine belt is installed correctly, and it would be quite difficult to get that wrong.

From memory, viewing from the front, I think the fan spins counter-clockwise?

 

[French02chris]

The viscous fan can only spin in the correct direction because it's driven by the pulley system. This assumes the serpentine belt is installed correctly, and it would be quite difficult to get that wrong.

From memory, viewing from the front, I think the fan spins counter-clockwise?

Thank you...mine spins counter clockwise..
I just had a doubt for a minute since the auxiliary fans spin clockwise.. Lol

 

[French02chris]

Thank you...mine spins counter clockwise..
I just had a doubt for a minute since the auxiliary fans spin clockwise.. Lol

I forgot to burp the cooling system when I refilled the radiator... So I will have to do it tomorrow morning when engine is cold!!!

 

[gsxr]

I forgot to burp the cooling system when I refilled the radiator... So I will have to do it tomorrow morning when engine is cold!!!

Oh yeah - any time you refill the system, it's good to disconnect the radiator hose and fill the engine block through the upper hose first (will take 4-5 quarts into the block). Then fill the rest via the plastic tank. After 1 heat cycle (up to operating temp, then cooled off overnight) you may need to top off with 0.5-1.0 quart.

If you only filled through the plastic reservoir, it may need 1-2 quarts to top off the next day. Fill to just a hair above the seam on the tank.

 

[nocfn]

un-realated issue but I have 3 bottles of new G05 on the shelf, and one decided to split the lower seem on the bottom center and made a huge mess on everything below. All of my bottles were swollen so I opened the cap. pierced a hole in the seal and placed them on the bottom shelf.

 

[gerryvz]

I would buy G05 as you need it, rather than stockpiling it. It's easily available at all McParts / FLAPS stores everywhere.

 

[mottati]

should the aux fans run with the AC on, or only under certain conditions (as on older MB models)? I've yet to hear/see my aux fans come on (6 months of this car), but the car is rock solid at 80C or a tick over (since replacing the thermostat) and AC blows cold. Weather warming up and planning a big road trip so would like everything as good as it can be.

Edit: ok to disregard this found another thread and have some things to troubleshoot.

 

[gerryvz]

should the aux fans run with the AC on, or only under certain conditions (as on older MB models)? I've yet to hear/see my aux fans come on (6 months of this car), but the car is rock solid at 80C or a tick over (since replacing the thermostat) and AC blows cold. Weather warming up and planning a big road trip so would like everything as good as it can be.

Edit: ok to disregard this found another thread and have some things to troubleshoot.

There are two phases of the fans being activated.

One is the "low speed" activation, which happens generally only when the A/C is running. Certain temperature and system pressure conditions have to be met == the fans do not automatically run during A/C operation (for example in colder ambient temps), but generally do.

The second mode is during high coolant temps, I believe when the coolant temp is sensed at 107C or higher, then the "high speed" fan activation happens to cool down the antifreeze circulating through the radiator and thus, overall engine temp. This happens on an "as needed" basis when the coolant hits this point, and the fans shut off when I believe it reaches ~90C?

 

[Jlaa]

un-realated issue but I have 3 bottles of new G05 on the shelf, and one decided to split the lower seem on the bottom center and made a huge mess on everything below. All of my bottles were swollen so I opened the cap. pierced a hole in the seal and placed them on the bottom shelf.

I would buy G05 as you need it, rather than stockpiling it. It's easily available at all McParts / FLAPS stores everywhere.

Ooffff... I should check on my jugs of G05 which are on a top shelf in the garage. I had bought them to replace the 8 year old coolant in my car, but when I checked the coolant in the car with the coolant test strips, the ph tested just fine --- probably because of the new-ish silica pack in the coolant reservoir...... and I didn't end up using the G05.

 

[gerryvz]

I would go ahead and flush and replace the coolant. If it's more than 3-4 years old, I'd replace it. Even in your climate where freezing isn't much of an issue.

 

[nocfn]

GVZ I had purchased some on sale, since I have two cars for it and I remembered that I had the SEC stash in storage which gave me extra. (this occurred when I replaced the E500 radiator with South African version not long ago)