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Discussion Starter #1
My name is Dave.
A communications engineer in Hampshire.
Recently purchased a Range Rover P38 2.5 DSE.

I have electric fans fitted to the radiator and the control system fitted by PO was not working just a switch on the dash to switch the fins on or off. Forget to switch it on and it overheats forget to switch it off and you get flat
Battery.
So I needed a proper solution
Thermostat is in line with top radiator hose. This needs you to cut and insert with new hose clips.
Relay is a scooter start relay available for a few pounds on eBay. It is off / on with contacts rated at 70 Amps
Relay numbers relate to the relay that I am using 85 / 86 = coil and 87 / 30 = contacts.
This design will also over run when the ignition is turned off.
End of overheating problems.

P38 fan relay.jpg

Dave
 

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1995-2002 Range Rover Classic
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1,413 Posts
why not find the reason for the overheating and solving? otherwise you are simply masking the problem, those fans are meant as auxiliary not main use. they will fail soon.
 

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JACK'S GRANDAD
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9,244 Posts
Lord, thats a bodge job if there ever was one.
Fix the root cause of overheating and stop masking it.
 

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Super Moderator
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2,311 Posts
Or refit the viscous coupling and fan that it is meant to have.
 

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Discussion Starter #5
The overheating fault was found. Hose from engine to heater had a split. The most difficult hose to change. This has now been fixed.
Not knowing what has been changed before this was the best fix to get the fans working.
This car has a lot of wires not connected and upgrade? modules installed that information is no longer available for.
Some time when available I will sort it all out.
This was posted in order to help someone who had a similar problem.

Dave
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,220 Posts
I went electric fan after finding that my viscous fan was causing the 6 month old (Quinton Hazel - not cheap britpart) water pump to start leaking... I think my fan coupling was imbalanced (after being off the vehicle for awhile, I saw stains of fluid down the fan VC.

The cost of a genuine VC outweighed the cost of putting a moster volvo fan/relay on (and given I replaced the VC on the fan for another owner with a cheaper Bearmach one which didn't unlock when it should - I wasn't going to go cheap if I replaced my fan VC) though from the get-go I fitted a machined alloy housing in the top hose with a proper radiator fan switch in it to control the relay for the Volvo fan (again from the same model Volvo the fan came from). No overheating issues, and my water pump now seems to not leak!

It sounds like the PO on yours who fitted the electric fan did a half-a**ed job on it and just wired it into a switch rather than a proper fan switch/controller. At least now you've finished the job it should run somewhat automatically...
 

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1995-2002 Range Rover P38A
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1,433 Posts
I have fitted a similiar temperature switch in the top hose of my 2000 DSE. However I have wired it to switch on the aircon fans at the front, either automatically or manually. It only switches on to supplement the cooling as I still have the original viscous clutch fan on the engine.
I recommend you do the same and refit your VC fan. A cheaper alternative for the diesel VC is ERR2266 (same as for the 300TDi). They are about £30 GBP each without the plastic fan bit.
The air blast from the VC fan when it bites and comes on is a lot more than an electric fan. I have towed at 40 deg C and it copes. I do have a bigger radiator however.
If you do decide to switch the aircon fans instead, note they have a continuous +12v feed and you need to switch the earth to ground via a relay.
 

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1995-2002 Range Rover P38A
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17 Posts
I confirm, this is easy mod.

I use standard radiator fan switch 92-87 degree. I put two wire from pressure sensor to this switch and when temp reach 92-93 degree aircon fans go in full speed.

I have use a different thermostat 82 degree from Mercedes with removed back flap.

 

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1995-2002 Range Rover P38A
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223 Posts
For USA members (petrol engine), you can install a W203 MB C Class Fan, and buy the controller from: http://www.ma-uav.com/Products.html

MB Fan example

Diesel, MY2000 have already the AC Fan on at 100 degrees.
 

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1995-2002 Range Rover P38A
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975 Posts
The MB fan must be around 600W (around 50A on full load) may be good on the petrol car as the alternator supplies 150A. With the diesel's alternator supplying 105A, can it cope up with full load like say night driving in heavy rain/fog?
 

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1995-2002 Range Rover P38A
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233 Posts
I like Marty_NZ have the volvo fan - it was mine that had it first, then we built his.

I do have a cheapie thermostat in mine though which appears to open at 82c rather than the 90 something of a genuine LR part. Which I'm fine with too.

Used a dual speed fan thermostat which I can't remember the two operating temps of, but the Volvo fan has a controller of its own that just needs a grounded input for low and high speeds. I believe my low speed comes on at 95, off at 90. High speed is 103, back to low speed at 98. To date, even in the mildly hot period of summer we've had this year, it never came on high speed, even in traffic with the AC working well.

Sure... a properly working viscous fan is fine too, but my coupling was locking up constantly, and a cheap replacement wasn't much better. The parts to make up the electric fan and its shroud didn't cost me much, and fabrication cost me nothing.





Startup current is I think somewhere about 70amps on high speed, but settles to 35-40 when running. Requires decent wiring to the power feed.
 
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