Electric fan or Viscous?

[GURU]

G'day all,

What do you think is better? I have a 300tdi that has the standard fan on it and it all works and have had no overheating issues ever.

But I keep hearing that changing it to an electric fan will gain me 10% more power and economy. Is it really worth it? Or should I run with "if it anit broke don't fix it"?

Dave

[chimpboy]

"if it anit broke don't fix it"?

^

[lokka]

"if it anit broke don't fix it"?

^

X2

Electric are shyte

[stuee]

"if it anit broke don't fix it"?

^

X2

Electric are shyte

Cant offer experience with diesel but can disagree with your comment for my v8. I've fitted AU thermos to mine and its made a world of difference. More power, cold air con all the time (even idling at traffic lights on a 35 degree day), small increase in fuel economy and very noticeable power increase (especially in summer when the viscous fan is usually on a lot).

Had my first test towing heavy loads the last few weekends towing trailer loads of pavers about on a hot day. Kept the temp down easy.

I went electric after having most of my cooling system replaced (flushed the block, new rad, new viscous coupling etc). Viscous fan worked but was not keeping the car cool enough IMO and the air-con performance would suffer on really hot days.

I'm stoked with my setup and will never go back to a viscous set up. The best part about it is the aircon improvement in hot weather and the ability to cool the engine down while sitting stationary. I can actually take the car 4wding in the middle of summer now and not worry about keeping the engine running with the aircon on while I get out and have a look around.

[chimpboy]

I don't think electric fans are shit, I just wouldn't be in a hurry to use them if my stock system was doing the job perfectly well. Certainly not for a gain in power which would would be a lot less than 10 percent imho.

[lokka]

"if it anit broke don't fix it"?

^

X2

Electric are shyte

Cant offer experience with diesel but can disagree with your comment for my v8. I've fitted AU thermos to mine and its made a world of difference. More power, cold air con all the time (even idling at traffic lights on a 35 degree day), small increase in fuel economy and very noticeable power increase (especially in summer when the viscous fan is usually on a lot).

Had my first test towing heavy loads the last few weekends towing trailer loads of pavers about on a hot day. Kept the temp down easy.

I went electric after having most of my cooling system replaced (flushed the block, new rad, new viscous coupling etc). Viscous fan worked but was not keeping the car cool enough IMO and the air-con performance would suffer on really hot days.

I'm stoked with my setup and will never go back to a viscous set up. The best part about it is the aircon improvement in hot weather and the ability to cool the engine down while sitting stationary. I can actually take the car 4wding in the middle of summer now and not worry about keeping the engine running with the aircon on while I get out and have a look around.

Yep ok well i had the same i fitted AU twin fan set up it only lasted about 3 months i was doing a fair bit of mud at the time and this is what killed the fans .
I then swiched to a single 16in davies craig it lasted about 6 months and failed the same as the AU set up .
Both fans were so called sealed units on disassembly i found them not to be sealed so il be sticking with a clutch fan now for simplicty and reliability .

[stuee]

Yep ok well i had the same i fitted AU twin fan set up it only lasted about 3 months i was doing a fair bit of mud at the time and this is what killed the fans .
I then swiched to a single 16in davies craig it lasted about 6 months and failed the same as the AU set up .
Both fans were so called sealed units on disassembly i found them not to be sealed so il be sticking with a clutch fan now for simplicty and reliability .

I can see how mud would quickly kill the electric thermos. I rarely venture into mud so not really an issue for me and I have a manual kill switch for water crossings and a can of wd40.

Id say that rather than being more simple and reliable, the viscous units are more robust. Can take more of a beating compared to the electric fans. Setup properly though, and looked after I don't see why the thermos cant be as reliable as a viscous setup. I'm fairly confident in my system and have a good idea of what would kill it and what wouldn't so I drive with that in mind.

I did a lot of research on my setup before going ahead with it. I'd suggest anyone who wants to do an electric setup do the same. And if you do mud, don't do thermos

[red90]

People that install cheap fans or use bad installation practices have given electric fans a bad name.....

Get a quality fan, install it properly and build a durable control system and it will be as reliable as a viscous setup.

I've run one for a couple of year with no trouble. Lots of deep wading and very deep mud. If the motor does die, another fan is $20......

[lokka]

People that install cheap fans or use bad installation practices have given electric fans a bad name.....

Get a quality fan, install it properly and build a durable control system and it will be as reliable as a viscous setup.

I've run one for a couple of year with no trouble. Lots of deep wading and very deep mud. If the motor does die, another fan is $20......

Yep maby in canada you can buy a quality fan for 20 bucks

Both set ups i used quality parts and both times muddy water killed the fans first i had the AU twin set up then a 16in davies craig .

When the davies craig gave up it was just on 6 months old i contacted them and asked why a so called sealed fan had holes in the case as it said on there web page it had a sealed motor even said it on the packaging well the rep told me that the 16in one was the only fan they do that is not a sealed unit and then i told him to look at his web page and he seen they had made a mistake and labeled the fan as a sealed unit .

I now have new 14 and 12 inch fans (as they are sealed units) and a new thermo controll sent to me by davies craig to keep me happy il probably never use as I just dont trust them I know if a clutch fan stops working I can bash the pin in the front of the hub to lock the drive to the fan to get me home bit hard to do that to a electric one if the motor carks in the bush

[chimpboy]

Despite the way they pitch themselves Davies Craig are nothing to shout about. I would probably have more confidence in a used oem 16" fan from a BMW than a new Davies Craig one to be honest.

[stuee]

Despite the way they pitch themselves Davies Craig are nothing to shout about. I would probably have more confidence in a used oem 16" fan from a BMW than a new Davies Craig one to be honest.

Yep. Davies Craig don't seem to have that good a rep at all around a lot of tech forums. Seem to be a cheap and cheerful brand.

The only reasonable quality fans I know of locally available are genuine Ford thermos. These cost a bucket load ($400+) but rfom what I've researched are far superior to all the non-genuine replacement parts. I've got a pair of cheapie AU fans which I got off a mate extremely cheap and they've done me well so far. Like I said before though i wont be taking them near mud any time soon.

A really good brand they I keep hearing about is SPAL. mucod on this forum is a big advocate of them too. If I had the spare cash I wouldn't have second thoughts about going SPAL fans.

[RRV839]

I put a new aftermarket viscous fan on the v8 rangie a couple of days ago, becasue when 4wding in the hils (not much airflow) or in the soft sand in high range she would overheat, but no probs otherwise, so i put a new one on and god does it suck some power and it is as noisy as hell, not too happy to be quite honest, i was going to go thermo's but decided against after what some ppl told me, now i am wishing i had gone electric

[lokka]

I put a new aftermarket viscous fan on the v8 rangie a couple of days ago, becasue when 4wding in the hils (not much airflow) or in the soft sand in high range she would overheat, but no probs otherwise, so i put a new one on and god does it suck some power and it is as noisy as hell, not too happy to be quite honest, i was going to go thermo's but decided against after what some ppl told me, now i am wishing i had gone electric

Did you change just the clutch hub or the whole fan ?

They do pull a lot of air and rob power tho maby the one you have isent right for your engin i know the one on my V8 disco makes plenty of noise tho i dont notice the power loss as much

[DL]

[quote="stuee"]
I'm stoked with my setup and will never go back to a viscous set up. The best part about it is the aircon improvement in hot weather and the ability to cool the engine down while sitting stationary. I can actually take the car 4wding in the middle of summer now and not worry about keeping the engine running with the aircon on while I get out and have a look around.[/quote]

Agree totally with Stuee. Have non-gen EL's in front of a 350 in a RRC with stock rad. One fan is on all the time, other on a adjustable temp switch. Done 60k km with no probs. Cost about $200 as a unit in a shroud. Runs a lot cooler in summer traffic and when crawling in the scrub.

Would not go back to the T-model Ford set up. Sure mud might kill them, but I don't use my POS as a submarine. Only using a 55 amp alt as well.

cheers, DL

[RRV839]

original fan, just a new hub, it is aftermarket but its from a landrover joint so hopefully its for a landrover at least lol, i probably wouldn't notice it much but ive gone from a completly stuffed one to a new on and i can notice it, i just have to push it harder, on my other cars i have had thermo's and think they great had two on the 79 2dr and they woker a treat, a few mates have them on gq's and they work great if setup properly.

[Philip A]

Agree totally with Stuee. Have non-gen EL's in front of a 350 in a RRC with stock rad. One fan is on all the time, other on a adjustable temp switch. Done 60k km with no probs. Cost about $200 as a unit in a shroud. Runs a lot cooler in summer traffic and when crawling in the scrub.

What happened to your condenser fans?

Are you comparing a viscous with or without condenser fans?

The condenser fans blow entirely through the condenser and on my car at least will keep the car cool with aircon on up to 48C or so.

I guess I am a bit biassed agianst electric as I had BOTH condenser fans fail at Kunnunurra ( well that's where I found out) probably as a result of deep water crossings about 9 months before.

When you fit the AU fans do you remove the condenser fans ? They take 7 amps each, so along with another 2 at around say 12 each will well overpower most alternators at idle.
My gauge never moves aircon or no aircon, so I respecfully suggest that you are masking another problem.
Regard sPhilip A

[DL]

Hi Philip,

No air con on my '74 POS.

Fans in shroud sit behind rad liberating a lot of space previously taken up by fan on water pump and associated shrouding.

Only prob that has been 'masked' (overcome) is that a stock RRC rad is marginal at keeping a 350 cool when an engine driven fan is fitted, on warm days in stop start traffic, or crawling around in the scrub. Twin thermo's are streets ahead here.

No benefit at highway speeds.

As previously posted, I don't regularly use my bus as a submarine so water is not an issue for me. (they have been submerged a couple of times)

Can see on the voltmeter when the second fan kicks in, but it is still well in the 'normal' range. Think there is amp usage data in the thermo fan sticky thread in 'Electrical' here on OL. Personally, I wouldn't want both fans kicking in at the same instant.

The set up I have is great for MY application.

Don't you run two alt's on your bus?

cheers, DL

[Philip A]

Only prob that has been 'masked' (overcome) is that a stock RRC rad is marginal at keeping a 350 cool when an engine driven fan is fitted, on warm days in stop start traffic, or crawling around in the scrub. Twin thermo's are streets ahead here.

I can see that with a 350 a 3.5 rad would be marginal!!!

I would think one of those desert Cooler jobs would be the go or even a 4 row 3.9/or 3 row NATRAD replacement.

I can see where you are coming from. Did you have a shroud made up to suit the 350 fan position? If not that is maybe why it overheated.

I had a Porsche 924 with aftermarket aircon that would not keep cool and it had 2 unshrouded electric fans. I ended up buying a factory aircon shroud with provision for 2 fans and the thing used to cool down when the aircon started. I also had them wired via relays so that 1 cut in with temp and the second with aircon on.

My problem is that the RRC has a small aircon condenser which only covers a small part of the rad. I fear that if I fitted pull through thermos and pulled off the pushers the head pressure on my aircon would go up. Rover covers this by having the fans on all the time the aircon is on, not just when the compressor is on.

Yes I have 2 alternators and I could split the load but Jeez the engine would probably stop with all fans blasting.
Regard sPhilip A

[/quote]

[DL]

Hi Philip,

Shroud to suit the 350 was on it when I bought it about 10yrs ago. It all worked fine with the stock RRC rad EXCEPT idling in traffic or crawling in the scrub on 40 deg days. It was simply an airflow prob.

Water temp would go up to about 3/4 and oil temp would get up to red. Had an LT95 in those days and temp could be reduced by raising the revs in neutral or with the clutch in at the lights, but hardly satisfactory. Rad was brand new.

Now it won't go over 1/2 on the water temp gauge or over 90 (1/2) on the oil temp gauge idling away in the heat.

That's the beauty of thermo's............ the air they pump is relative to the heat of the coolant (need), not road or engine speed.

Also the shrouds on these Ford things have way tighter tolerances than you can use with a fan attached to a motor and the surface area of the rad closely exposed to the fans is much more than a normal fan. There is a pic of one in the sticky mentioned in my last post.

We need someone running air con and thermos to chime in.

cheers, DL