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1995-2002 Range Rover P38A
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Discussion Starter #1
Hi,

I'm thinking of fitting an electric fan in place of the VC fan. I've got a BMW radiator fan rated at 400 W.
My main concern is the alternator (VALEO) which has a 105 A (when new) output. I have checked online for info on alternators but couldn't get any clear idea as to what the output at idle. A guesstimate would be around 35% . i.e 35 A at idle. If that's correct, imagine car at stop lights in a rainy night with AC, head lights, wipers and ABS/EAS pumps running. ?

Can someone tell me the ;
1. alternator output at idle (750-800 RPM)
2. power needs of AC compressor & fans
3. power needs of ABS pump and EAS pump.
4. power needs of wiper motor at full speed

I have a thermo switch which can operate the fan at 95 C (too high?) and quits at 88 C. I have a doubt on this as the BMW M51 engine's standard running temp is 90 C and hence 2 degree margin will keep the fan running most of the time. Any advice on this thermo switch? The car's water thermostat(BMW genuine part) opens at 80 C.

Also, would like to know whether the existing fan cowl is capable of holding the fan (700 gms), for me to attach the fan to the cowling with ZIP ties.

Hopefully Im not asking too much.
Thanks in advance
 

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1995-2002 Range Rover P38A
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I’m not sure if trying to tie a 1/2 hp fan to a flexing fan shroud with zip ties would be a recipient for disaster or not, but I can imagine a fan at full speed chewing its way into a radiator core is something let go ......

Convert it by all means, make decent brackets and do it right. The alternator will cope given the fan is only likely to run in traffic and any decent battery it going to cope with it.
 

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Discussion Starter #4
Been done on a V8 using a Volvo fan, no problems with the battery going flat or the alternator being overloaded, see V8 electric fan conversion - Topic - rangerovers.pub
Thanks Richard-G. That's very encouraging.
I'm going to fabricate a cowling from wifes , aluminium cake tray :)whistle: ) & complete the mounting part.
Still I'm bit worried about the alt capacity. I see that the V8 alt gives 150A. This should give about 50A at idle.
Also, I want to gauge the fan on/off frequency to avoid it coming ON like every other second which will definitely create issues with other fellows who want few amps to feed.

Let me get that tray, first.
 

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1995-2002 Range Rover P38A
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Thanks Richard-G. That's very encouraging.
I'm going to fabricate a cowling from wifes , aluminium cake tray :)whistle: ) & complete the mounting part.
Still I'm bit worried about the alt capacity. I see that the V8 alt gives 150A. This should give about 50A at idle.
Also, I want to gauge the fan on/off frequency to avoid it coming ON like every other second which will definitely create issues with other fellows who want few amps to feed.

Let me get that tray, first.
Please show us pictures when you're done...
 

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It's your car, of course, but I don't get why you would want to do this. You currently have a reliable cooling source, and you live in a hot country....isn't it better to have the viscous one? Or you're regularly fording deep water?
 

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1995-2002 Range Rover P38A
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Discussion Starter #7
This is my daily driver. I don't think it had gone off road ever and no intention too.
My main issue is noise. In the morning few seconds but other times with AC on, it's roaring like a hungry lion. I live in a slight hilly area but the car sounds like hiking Everest on 1st Low with max RPM where the actual RPM is about 2000. Even at stop lights when start to move quickly(if anyone can call it quickly) it roars. Don't mind if it moves in relation to the roar, but you know diesel P38, no horses all buffaloes.

Yet I'm little reserved on electric fan as I'm unable to get the correct ON/OFF temps. The link above by Richard-G, shows the setup on a V8 but it's temps are different to diesel.
 

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1995-2002 Range Rover P38A
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if you want to put a thermo fan on your rover then do that, but it sounds like you need a new viscous fan coupling , on cold start it should be doing very little. first sign of viscous fan problem is noise of the fan
PS i dont recommend thermo fans as they don't move enough air , if you get caught in traffic it will boil, if you have to climb hills there is a good chance it will boil, if you do decide to go 4x4 it will boil but let us know how you go.
 

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Sounds like your viscous is seized. Normally it will roar for the first 20-30 seconds as it locks up due to the silicone having drained down but once running it should be quiet until it gets hot enough to need it.
 

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I wouldn't do it Kapila. There are already two large electric fans at the front. Designed for the aircon primarily, the wiring can be modified so they can be switched on manually or they can come on using a temperature switch fitted into the radiator bottom outlet hose.
As Mad as said, the viscous fan moves far more air than any electric fan can. Keep the viscous fan. It can be repaired yourself cheaply by replacing just the middle bit. Unbolt it from the plastic fan blades. A Disco 2 fits from memory.
 

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Discussion Starter #11
You are correct Dave. About 5 yrs back I replaced the VC coupling with a 300TDI part.( ERR2266 IIRC.)
I have no special favour for the electrical fans, knowing that we have a 100 A alternator (when new) and thermally challenged head in a chipped engine.
With AC on and around 35 C temps here, engine is always hot and the temp gauge needle is slightly above 12 o'clock.
Few weeks back, once it went to a position between 12 and 1. Checked temp with Nanocom and it was 95 C.

It's the annoying noise and the people must be thinking that my car has only one forward gear.

Then it's time to change the VC centre. Will have to wait till opening the Colombo airport in August.
Good that I didn't cut the alum cake tray.
 

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Nothing wrong with running at 95 degrees, it's a pressurised system and even running at 105 would be perfectly acceptable but 95 would be almost perfect. Viscvous fan shouldn't be locked up at that temperature either.
 

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If you can source a spare used fan from a scrapyard, you could rebuild it with a new coupling, so one out, one in, minimum disruption to your daily driver.
Getting the fan off the water pump can be difficult.
 

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Discussion Starter #14
Richard G: This is a diesel BMW engine, notorious for head cracks, as I've heard. Unlike the V8 , letting temps go above 100 C will be asking for trouble.

Dave: There are no scrap yards here with P38 parts. Only Defender yards. I can source a 300TDI VC unit but it will be cost me close to new part. I think it's better I get a new VC from Island44 or similar party. Getting the fan off is not that hard but need to remove the top hose and cooling system burping afterwards.
 

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As above, don't replace the viscous with an electric fan, especially if you're worried about overheating. The viscous is a far better (stronger) fan then any electric one the battery/alternator can handle. Don't get me wrong, the alternator is more than capable of supplying current to an electric fan, but those are not as strong as the standard viscous so you will be downgrading.

From what you're saying, it does sound like you need a new viscous coupling, to cut down on the noise.
Temperature going to between 12 and 13 on the gauge is nothing to worry about if the conditions call for it. I.e hot, high load, low speed... I had the same on my diesel when towing a heavy trailer uphill. At higher temperatures the radiator is more effective (bigger difference between coolant and ambient air), so it should reach an equilibrium and be fine.

Filip
 

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Discussion Starter #16
Okay, I 'll give up this idea and order a new VC fan hub from Island 4x4.
 
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