Thread: 3.9 V8 ran hot yesterday....what now?

I dont know why anyone would replace the original with something less efficient,, but,,
Ford actually do a 16"(17?) single thermo that bolts on,, it covers more rad area then the twins and is newer!!

Originally Posted by Rick1970

When I put EL thermos in my old rangie, replaced sensor in the top of thermostat housing to a lower setting one to activate them, think they also make a dual one so you could run them as two speed if desired.

I bought a Davies Craig fan controller from SCA it works pretty good just has a dial on it. A lot of wiring involed with 2 fans it needs relays and all that but it's only single speed switch which sorta sucks. I saw online they have a digital version for in the car by the looks, if I keep the thermo I might look at getting that it does a few other things plus has the temp gauge.

Originally Posted by Pedro_The_Swift

I dont know why anyone would replace the original with something less efficient,, but,,
Ford actually do a 16"(17?) single thermo that bolts on,, it covers more rad area then the twins and is newer!!

This is true, wouldnt do it again, quite happy to leave the V8 Disco with a viscous fan

Originally Posted by Rick1970

This is true, wouldnt do it again, quite happy to leave the V8 Disco with a viscous fan

There is one simple reason i would not keep them.

THERE A BITCH TO GET OFF!! On the D1 i had to make my own damn spanner to get the thing off!

Surely that alone is a good enough reason to turf it right?

Im all about modifying to make **** easier.

Thermos work just fine and some of them have some good adjustable stuff which is another dial on the dash and we all want that right?

Meh i recon viscous fans are crap. Annoys the hell out of me in the morning actually.



**Also get that comp tester. Good tool to have and it does give piece of mind.

so,, sort of planning to fail?

anyway if your thermo's last half as long( or shift half as much air--) as the genuine item you can consider yourself really lucky,,,

I like thermo so far but I need to get an aftermarket gauge to see if it's really helping. I got both running now I'm pretty sure on the AU 1 fan spins faster and I kept blowing a fuse. The car didnt get hot with only 1 running today but i was paranoid as hell. The only thing letting it down is the shroud but I'm gonna make one up. Overall fan size I'm still convinced the twin fans cover more area. Looking at the old shroud it was really only in the centre with a heaps of space each side, but it did hang lower than the radiator. But if they can cool a 351 they can cool a rover if setup right.
Do the pros out way the cons....probably not.
I like the idea of putting in a kill/override switch for going through puddles or climbing hills lots splash from the viscous. And if it's like others they don't spin after 2500rpm unless hot, to be able to switch the fan on when towing or going up long hills is always a plus.
It does take strain off the engine but adds strain to the alternator and battery.
Life span well I've never had a thermo go on me but I've had 3 viscous fans die. I'm sure thermos die eventually also.
Noise is a same same, either airplane or loud electric fan sound I prefer the airplane from the viscous.
Viscous is a 1 piece unit which is easy to replace (once you get it off) I ground down a falcon 6 spanner to fit. Thermo is a pain to setup if you go the path I went but you have more control with it.
I like that the viscous is always sucking air through even if it is only some. The thermo is either on or off, I need to set up 2 controllers 1 for each fan.
More money invested in a thermo compared to a cheap viscous.
Hopfully get some photos up soon and a gauge to see how it's actually doing.
Cheers Jim

Two switches yes, wire fans through relays so they run in series for low speed, and parallel for high speed.
Keep an eye on the temps in the really hard going stuff, sand, long hills, towing etc......that’s where the extra air shifted by the original fan can become noticeable

Can't understand the problems people seem to have with getting viscous fans off. I have a double ended spanner (via Roverlord, if memory serves - suits V8, Tdi or Td5). One, or at most, two hits with a hammer, and undo by hand. Easy peasy!
As far as efficiency goes, provided the bi-metal spring is clean, and the fluid hasn't leaked out, they work on the temperature of the airflow through the radiator, regardless of engine revs.