mmgemini Posted September 17, 2013 Share Posted September 17, 2013 Nobody seen a viscous fan go through a radiator core ? Plenty of broken blades. Plenty not working properly... Quote Link to comment Share on other sites More sharing options...
duncmc Posted September 17, 2013 Share Posted September 17, 2013 Personally, I don't like electric fans: to me their biggest disadvantage is that for 99.9% of the time (in the UK at least) the fan (whether electric or viscous) on a Land-Rover is not needed - then on the one stinking-hot summer day when it is needed the electric fan will be found to have stuck brushes, a corroded earth connection, seized bearings - or all of these. On transverse-engined cars (apart from the old BL Minis/1100s etc and one wacky little Peugeot that used a "round-the-corner" belt to drive a fan behind a front-mounted radiator) an electric fan is the only practical option - for inline engines I'd go with a mechanical fan every time - for simplicity and reliability. Whether you use a traditional viscous coupling or a magnetic clutch to control the fan is all a matter of taste and space. I run a couple of ex-mondeo air-con fans instead of my viscous fan on my RRC 3.9. The fans come on every day at some point. Usually that is in town sat at traffic lights. That happens every day, even in winter, ok maybe not when its -10 or whatever, but most days they are on. The only downside to mine is that they are noisy and I would like some quieter ones. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted September 17, 2013 Share Posted September 17, 2013 Maybe that is the difference? ..... anecdotally electric work well on petrol engines where they will be switching on and off all day getting regular use, but aren't so good on diesel engines where they may remain for months without switching on and sieze up. Discuss Quote Link to comment Share on other sites More sharing options...
smallfry Posted September 17, 2013 Share Posted September 17, 2013 Maybe that is the difference? ..... anecdotally electric work well on petrol engines where they will be switching on and off all day getting regular use, but aren't so good on diesel engines where they may remain for months without switching on and sieze up.Discuss This is very true................maybe a manual overide switch to give it a bit of exercise now and again would be a good idea ? Rather like you are supposed to do with aircon. My old series 3 was fitted with a 3.5 EFI engine and used the stadard radiator. Had no fan whatsoever and overheating was never a problem. Even in traffic. Did have vent holes in the bonnet though. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted September 17, 2013 Share Posted September 17, 2013 Twin (I think mondeo) fans on mine. Only come on about once a year when the rad is chock full of mud. Work when they're needed! Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted September 17, 2013 Share Posted September 17, 2013 As an aside I wouldn't underestimate how dangerous the electric fans can be, one of the guys on the Mud Monsters face book group had to have skin grafts after having an electric fan start up and catch his fingers when he didn't expect it. Left the bone poking out, was a vectra 1.8 fan I believe. Quote Link to comment Share on other sites More sharing options...
Boydie Posted September 18, 2013 Share Posted September 18, 2013 Apart from the obvious power saving of running an electric fan set-up - whicjh was my reason for installing one - my research has indicated that the original viscus fan is the way to go, to confirm this just look at most north /south engines cars and trucks - the majority have belt driven fans and viscus at that, despite a viscus fan being more expensive to manufacture than an electric fan (ceck out a Mack, Kenworth, Freightliner, Peterbilt, Volvo or Ivico truck - all have belt driven viscus fans, electric fans are generally installed on east-west engine set-ups and utilise thin 2 core radiators. The design of a viscus fan is such that even if the silicon goo leaks out it will still drive - or at least at 50% efficiency. The problem with the Land Rover fan isnt that its viscus but rather the location of the bi-metalic control spring -- its in the air stream rather than in the water. Most of the systems I've seen have the bi-metalic coil, or wax pellet in the water jacket. This is generally because the fan runs off the water pump shaft and therefore having the operating device in the water is easily incorporated in the water pump/fan shaft design, having the device in the air stream is not so efficient as it can be affected by humidity and the enthalapy of the air, for example your water is hot but its a very warm day with high humidity - mist even - the spring will be cooled down by the moist air and the fan will not fully "engage" and be drawing less than the required ammount of air flow. The other consideration is that to draw the same volume of air through a 4 row core as a belt driven fan you will need a fan motor that draws around 40- 50 amps or in imperial terms 5 - 7 1/2 horse power --- and thats a bloody big fan.!!!! A possible solution would be to doctor the electric clutch off an air conditioning compressor and fit it to the existing fan dive pulley with a solid fan (sans viscus drive) with a thermostatic switch this would give you all the drive horse power needed with the flexibility of having the fan only operating when you need it, but again if the clutch fails you are well and truely shafted ! Quote Link to comment Share on other sites More sharing options...
Boydie Posted September 18, 2013 Share Posted September 18, 2013 CwazyWabbit, Diahatsu Charades use the reverse gear to operate the A/C system to ensure it has a regular operation, every time you engage reverse gear you switch on the A/C - you could incorporate this into your cooling fans with a suitable sized diode to prevent feed-back if the fan is already running due to high temperatures and you engage reverse as well. Quote Link to comment Share on other sites More sharing options...
benthng Posted September 18, 2013 Share Posted September 18, 2013 Nissan Cefiro twin dual speed fan fits very well too, it's a teensy bit longer otherwise almost clip on. Can be used with Alfa 33 dual stage temperature switch thread size M22 which will fit the existing manifold. IIRC it trips on at 88 C off at 83 for low fan speed and the 2nd switch point at 93C and off at 88c Quote Link to comment Share on other sites More sharing options...
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