bye bye fan clutch - Page 4 - PeachParts Mercedes-Benz Forum

schwarzwagen · #46 04-11-2005, 06:45 PM

Quote:

Originally Posted by Hit Man X

Amperage to run them, 70A alternator is not enough to run them.

I had a 105A on my Z71 and it was insufficient with the A/C on and the fans on low speed.

>130A is needed to properly run a pair of e-fans or one good e-fan. A Ford Taurus fan would work well and are CHEAP as a mofo here. Pull some insane CFM too.

i think people should do the 143-150a upgrade anyway for safety. a 70a alternator is pretty worthless if you have high watt bulbs or a stereo, both of which i have now.

Hit Man X · #47 04-11-2005, 07:06 PM

Quote:

Originally Posted by schwarzwagen

i think people should do the 143-150a upgrade anyway for safety. a 70a alternator is pretty worthless if you have high watt bulbs or a stereo, both of which i have now.

I concur, I now have a 130A on the Z and a 200A on the F150.

Now if you can find an easy swap 130-150A for the 617 motor I'd be very happy... best I found that was direct was 90A.

OhioSDL · #48 04-11-2005, 10:57 PM

I cant wait for it to get really hot so i can see how these fans really work. the temp needle dosent dare get close to 100 deg right now.

Question. should they run after the vehicle is off?
it isnt any longer than about 20 seconds or so.

gsxr · #49 04-11-2005, 11:26 PM

Quote:

Originally Posted by schwarzwagen

i have been interested for some time in converting to an electric fan. ever since i replaced vfc with a *brand new one,* i have been dissatisfied with it. the engine ran hotter from day one, and several weeks ago it just quit work altogether. i took off the bimetallic strip and adjusted it a bunch of times and have yet not been able to get it to work properly all the time. the viscous fluid is fine because the fan will engage at full strength, its just a matter of getting it to activate proper and at the right time. right now, it comes on erratically on the highway, and around town the engine gets up to 100C or more before it engages and even then it will not disengage right. it will stay on so long that the thermostat will actually close up and the engine will get hot again and when you stop the coolant temp shots up past 100C!! so frustrating.

i dont know if i should try another vfc, thinking that this one was defective, or just get an electric fan and call it a day.

i am wondering why people are so against electric fans? all mbs are now cooled by electric fans. i have heard from manufacturer sources (not mb)that electric fans require less energy and are more fuel efficient and more reliable than vfc systems. what is all the fuss then??

1) Sounds to me like your new VFC is working as intended. Temps up to 100C are normal. Temps above 100C are usually not (unless ambients are very high and/or there's extended full load.)

2) The VFC won't engage properly if the radiator has a 'cool' spot ahead of the fan. This can be very hard to figure out and more than one good clutch has been replaced when the radiator was the real problem. Also need to make sure the condenser fins are clean in front of the fan area to allow proper airflow.

3) The new/replacement VFC for the 603 is actually a 606 clutch with plastic fan. It's my opinion that this newer clutch is designed to engage at a higher temperature to improve fuel economy by raising engine temps to the 90-100C range, instead of the previous 85-90C range that most people expect. The FSM details exact temps for operation of the old clutch but is annoyingly silent on the details of the 606 clutch.

4) Aftermarket electric fans have a bad rap because they *usually* don't pull enough CFM to properly cool the car. And trying to get one large enough to fit is often a problem. Then there's the issue of the alternator upgrade and required electrical cable size increases, battery terminal modifications, etc - it's a lot of work. And for what? Don't forget they are usually a LOT noisier than the stock VFC setup. Now, factory electric fans are a TOTALLY different discussion. Mercedes can engineer an OE setup with the proper electrical system, CFM, and noise properties. But trying to retrofit this on an older MB is usually a waste of time and money - IMO, anyway. I have no plans to ever replace the VFC on my car. The one and only reason I'd ever consider it is if I were to go the SuperTurbo route and needed to relocate the radiator 2 inches back, and had to ditch the VFC to make room. (I don't plan to ever do this, btw... and it works in Finland because they're at roughly the same latitude as Alaska, if you get my drift.)

schwarzwagen · #50 04-12-2005, 02:58 PM

Quote:

Originally Posted by OhioSDL

I cant wait for it to get really hot so i can see how these fans really work. the temp needle dosent dare get close to 100 deg right now.

Question. should they run after the vehicle is off?
it isnt any longer than about 20 seconds or so.

volvos run the fan after shutoff, so do vws (i think). if i had an electric fan, i would let it run after shutoff as well. sometimes, if its a hot day, i will leave my key at the 'on' position and let the accessory fans come on after shutoff to cool down the engine bay.

sixto · #51 04-12-2005, 03:10 PM

[QUOTE=schwarzwagen]right now, it comes on erratically on the highway, /QUOTE]

Should the fan come on on the highway? There's probably more flow through the radiator at 35 mph than the fan can hope to blow. Plus the VCF has an rpm cut-off somewhere between 2500 and 3000 rpm IIRC.

Is the the existing electric fan doing it's job in low speed and high speed modes?

Sixto
95 S420
87 300SDL

ke6dcj · #52 04-12-2005, 03:17 PM

The electric fan I've chosen is a SPAL electric puller-fan: pn#30100846, with a CFM of 2780 @ 25Amps, with the folllowing dimensions: 23.46" x 16.26" x 2.6" deep (4.25" deep at motor).

I use a Derale adjustable thermostat with a HELLA relay replacing the crappy relay supplied.

I used this for BOTH our 500E and W124 C36-powered wagon.

Keeps the temps just right, even in the brutal heat and humidity of Florida.

IMHO, with the stop-n-go traffic we have, it does a better job than the viscous fan which needs to have the engine-rev'd to really work (remember, viscous fan disengages at 3800-4000 RPM).

Also, the pictures don't show it, but I was able to keep the stock fan shroud, which helps.

:-) neil

FWIW: having the viscous fan removed, also means it is easier to change belts, and do other engine work that needs the viscous fan removed.

Hit Man X · #53 04-12-2005, 03:24 PM

What's the word on 130-150A alternators...

schwarzwagen · #54 04-12-2005, 04:42 PM

Quote:

Originally Posted by gsxr

1) Sounds to me like your new VFC is working as intended. Temps up to 100C are normal. Temps above 100C are usually not (unless ambients are very high and/or there's extended full load.)

the vfc will not engage until very close to 100C. the problem is this, the darn thing once engaged will not disengage properly. it stays on so long, that the thermostat closes up completely in an attempt to maintain the engine temp around 82C. once the vfc finally disengages, the temp creeps back up, and the cycle starts anew. when you stop, the temp spikes up rather alarmingly due to the fact that the thermostat is closed! i know the thermo works because i watch the temp gauge like a hawk, and can see it trying to compensate for the disengagement problem with the vfc.

Quote:

Originally Posted by gsxr

2) The VFC won't engage properly if the radiator has a 'cool' spot ahead of the fan. This can be very hard to figure out and more than one good clutch has been replaced when the radiator was the real problem. Also need to make sure the condenser fins are clean in front of the fan area to allow proper airflow.

it could certainly be the radiator, i have no way of knowing without a laser temp gauge or something. the condenser, however, i replaced at the same time as the vfc and i cleaned all the crud out from the fins of the radiator and flushed the system and refilled with the proper coolant/water ratio, etc.

Quote:

Originally Posted by gsxr

3) The new/replacement VFC for the 603 is actually a 606 clutch with plastic fan. It's my opinion that this newer clutch is designed to engage at a higher temperature to improve fuel economy by raising engine temps to the 90-100C range, instead of the previous 85-90C range that most people expect. The FSM details exact temps for operation of the old clutch but is annoyingly silent on the details of the 606 clutch.

if it would stay between 90-100C i would not worry about it, but now it goes to 105C sometimes, then back to 82C, then back up to 100-105C as the thermo tries to compensate for the vfc engagement problem.

Quote:

Originally Posted by gsxr

4) Aftermarket electric fans have a bad rap because they *usually* don't pull enough CFM to properly cool the car. And trying to get one large enough to fit is often a problem. Then there's the issue of the alternator upgrade and required electrical cable size increases, battery terminal modifications, etc - it's a lot of work. And for what? Don't forget they are usually a LOT noisier than the stock VFC setup. Now, factory electric fans are a TOTALLY different discussion. Mercedes can engineer an OE setup with the proper electrical system, CFM, and noise properties. But trying to retrofit this on an older MB is usually a waste of time and money - IMO, anyway. I have no plans to ever replace the VFC on my car. The one and only reason I'd ever consider it is if I were to go the SuperTurbo route and needed to relocate the radiator 2 inches back, and had to ditch the VFC to make room. (I don't plan to ever do this, btw... and it works in Finland because they're at roughly the same latitude as Alaska, if you get my drift.)

my big issue with the vfc is not its operation (when working right), its the stupid little bimetallic strip that actuates it. if the strip does not reform itself upon cool down, the thing will not let the vfc disengage properly. hence, the vfc will come on erratically and go off erratically as the strip deflects with the heat.

schwarzwagen · #55 04-12-2005, 04:44 PM

[QUOTE=sixto]

Quote:

Originally Posted by schwarzwagen

right now, it comes on erratically on the highway, /QUOTE]

Should the fan come on on the highway? There's probably more flow through the radiator at 35 mph than the fan can hope to blow. Plus the VCF has an rpm cut-off somewhere between 2500 and 3000 rpm IIRC.

Is the the existing electric fan doing it's job in low speed and high speed modes?

Sixto
95 S420
87 300SDL

the vfc starts to decuple from the pulley at 3500 rpm if i am not mistaken

schwarzwagen · #56 04-12-2005, 04:51 PM

Quote:

Originally Posted by ke6dcj

The electric fan I've chosen is a SPAL electric puller-fan: pn#30100846, with a CFM of 2780 @ 25Amps, with the folllowing dimensions: 23.46" x 16.26" x 2.6" deep (4.25" deep at motor).

I use a Derale adjustable thermostat with a HELLA relay replacing the crappy relay supplied.

about what was the cost?

Quote:

Originally Posted by ke6dcj

I used this for BOTH our 500E and W124 C36-powered wagon.

Keeps the temps just right, even in the brutal heat and humidity of Florida.

IMHO, with the stop-n-go traffic we have, it does a better job than the viscous fan which needs to have the engine-rev'd to really work (remember, viscous fan disengages at 3800-4000 RPM).

exactly, the engine must be revving to get any help from the vfc, that's the real reason why i like the electric fans. the electric fans work independently and can go on and off as required by temps.

Hit Man X · #57 04-12-2005, 05:10 PM

I'm all about e-fans, both my trucks I've converted to e-fans. Not to mention the power gains (about 7rwhp from unlocked clutch) there's a tad of economy to be had in there too.

BUT - unless you have a charging system up to the task I do not recommend it. That's the key. 65-75A alts will not be sufficient.

Best fan controller I've found is the DC Control unit. It's similar to the FlexALite VSC but far better. Still soft starts the fans and runs them in low speed mode until coolant temps demand otherwise.

dieseldiehard · #58 04-12-2005, 06:53 PM

Quote:

Originally Posted by Hit Man X

BUT - unless you have a charging system up to the task I do not recommend it. That's the key. 65-75A alts will not be sufficient.

Best fan controller I've found is the DC Control unit. It's similar to the FlexALite VSC but far better. Still soft starts the fans and runs them in low speed mode until coolant temps demand otherwise.

Why wouldn't a 65 A alternator like the AL69X be fine? I haven't figured in a big thumper sound system or ham radio, but the lights and A/C fan should not draw much over 200 Watts (15 amps) - where is the other 50 A going in a normal vehicle (Not including seat heaters and window heater)?
There should be 20 amps easy for the fan(s)
Tell me more - where is this DC Control unit made? I like the idea of a soft start as well as variable speed mode!

Hit Man X · #59 04-12-2005, 07:04 PM

Quote:

Originally Posted by dieseldiehard

Why wouldn't a 65 A alternator like the AL69X be fine? I haven't figured in a big thumper sound system or ham radio, but the lights and A/C fan should not draw much over 200 Watts (15 amps) - where is the other 50 A going in a normal vehicle (Not including seat heaters and window heater)?
There should be 20 amps easy for the fan(s)
Tell me more - where is this DC Control unit made? I like the idea of a soft start as well as variable speed mode!

Think about when the A/C is on also (even on low speed), there's a solid 20A at least. The compressor hurts a lot. Then add headlights to the mix, defroster, the system gets taxed WAY too fast for my tastes. I figure we only get about 30-40A max at idle. It simply is just enough to get by. If you don't have the voltage to keep up at idle everything slows down... that means the fans can't cool as well (including the aux A/C fan up front), the A/C blower fans blows slower, etc. Not good.

A 105A I have on my current Z and would be undercharged at idle speeds still (about 45A at idle).

The 130A I have on there now is fine unless EVERYTHING is on down to the seat warmers, defroster, A/C, and fans at idle. You need about 65-75A at idle.

www.dccontrol.com I think is their site. Also FlexALite has the VSC, if you run it get the four heat sink one. It's what I have on the Z until I upgrade to relays. Running at 50% speed when the A/C on doesn't shock the charging system nearly as bad when they kick on and as coolant temps rise so does the fan speed. A 35A from DC should be fine, they also have a 60A.

dieseldiehard · #60 04-12-2005, 07:16 PM

Have you seen the wire that supplies current to the compressor clutch? It can't be more than 5 or 10 A unless there is something I haven't taken into account.

The pusher fan in front of the radiator is probably the largest OE current drain outside the lighting. I have Hella H3's in place of the 5-3/4 fogs. std 55 W bulbs. ANd I use Hellas below the bumper on one of my W123's. No big deal, I really dislike using 100 W bulbs and people that use them are on my spit list too

I am going to install an 80-0-80 amp gauge in my '79 300TD when I get the time to lash it in and then I can see firsthand how much current it needs. I will be shocked if I don't have at least 20 A left to run puller fans (I have been wanting to get rid of the clutch driven fan for a long time)

PS Thanks for the link to dc controls! I appreciate that!