Electric fans/warped manifolds

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tom1979

tom1979

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i think this unlikely but I’m soon fitting an Allisport radiator with electric fan to my Defender. My mate said tonight he’d heard that electric fans can cause the exhaust manifold to warp as there isn’t a constant flow of air. I’ve never heard of this, had anyone else?
 
Exactly I can’t see how a fan in front of the engine could affect anything significantly, especially considering ho rapidly and often the exhaust temp changes.
 
tom1979 said:
i think this unlikely but I’m soon fitting an Allisport radiator with electric fan to my Defender. My mate said tonight he’d heard that electric fans can cause the exhaust manifold to warp as there isn’t a constant flow of air. I’ve never heard of this, had anyone else?
Click to expand...
But what about the muffler bearings?
 
I think that the viscous fan is always rotating, so will produce a steady airflow over the engine.
Where an electric fan will wait until the engine starts to get too hot, then suddenly kick in and cool everything down before shutting off again.
Having said that, the viscous fan will stop rotating when you turn off a hot engine, causing heat soak, where an electric fan may continue running.
Pretty much every car on the planet has an electric fan these days.
I would guess that a viscous fan would in some cases be better in a vehicle used for extreme off road and deep water crossing where an electric fan may stall or get water ingress.
 
An electric fan can be better in deep water too as it can be just turned off. A viscous fan can act as a propeller in the after and the blades can sometimes pull themselves through the rad.

The TD5 viscous fan is still better at cooling than the Alisport one though. I was going to get one but he recommended keeping the Viscous if doing heavy towing etc.

I still think I'll get one though as my TD5 overcools anyway and can never keep the heater matrix properly hot to keep the cabin toasty in winter unless working the engine hard
 
We use to have an electric fan fitted on our other 4x4 for off road driving and deep water wading had it running off of a dash mounted switch never had a problem. Most of the time it was off as the engine ran cool any ways. When at pay and play site etc we just flicked it on until the water runs then turned it off while driving past all the modded rover v8s who flooded there electric with the viscous fan.

The bonnet ups lol
 
tom1979 said:
i think this unlikely but I’m soon fitting an Allisport radiator with electric fan to my Defender. My mate said tonight he’d heard that electric fans can cause the exhaust manifold to warp as there isn’t a constant flow of air. I’ve never heard of this, had anyone else?
Click to expand...
the reason its a common issue the exhaust manifolds warp because they are not heat treated from factory ..using the engine on a daily basis this actually heat treats the manifold warps to a position to some point..once the material has found its position then it ready to be skimmed the viscous fan locks and unlocks maybe ask your mate about air flow that is travelling through the radiator while travelling forward at 100 KPH
if you do convert your engine to run electric fans make sure your have the correct cowling to suit the size of fans fitted .. and a switch on the thermostat to regulate when the fans kick in and kick out unsure about the defender but my 2002 that runs the same engine has electric fan also... I geuss we have to expel some heat from the air con condenser where is a locked viscous doesn't make the howl sound to much at low RPMS ..
and if the defender uses the same coolant temp sensor installed to the disco 2 .be very carful as this is very inaccurate
 
Last edited:
ozzyboydeano said:
and if the defender uses the same coolant temp sensor installed to the disco 2 .be very carful as this is very inaccurate
Click to expand...
the sensor itself if it's genuine is quite accurate, the problem is with the gauge which goes to the middle at 70*C and stays there up to 120 so without an additional gauge which shows the real temp you can drive it at 115*C without even knowing it and that's not healthy on a long run cos the injector seals and the harnesses + connectors will be all "tenderised" by heat also the higher the coolant temp is the higher the fuel temp will be too and especially if the fuel in the tank is not above half the pump will suffer as well to not mention that the engine power will be reduced too due to the high FT input
 
sierrafery said:
the sensor itself if it's genuine is quite accurate, the problem is with the gauge which goes to the middle at 70*C and stays there up to 120 so without an additional gauge which shows the real temp you can drive it at 115*C without even knowing it and that's not healthy on a long run cos the injector seals and the harnesses + connectors will be all "tenderised" by heat also the higher the coolant temp is the higher the fuel temp will be too and especially if the fuel in the tank is not above half the pump will suffer as well to not mention that the engine power will be reduced too due to the high FT input
Click to expand...
thanks mate it was a typo . was meaning to say temp sender gauge

back in my younger days I had an old D21 engine in a Nissan terrano the thing was gutless to begin with so I decided to add in 2 12 inch eletro fans this worked good normal driving but boiled its ass off soon as I went off road or under heavy load ... I then resorted back to viscous only that I never had the correct cowling to house the thermo fans

I can also relate the fuel temp as back a while ago that my air con was struggling due to the design that the heaters are full time flow .turned out you helped me kill 2 birds with one stone ..not only my air con works great but also my fuel filter isn't burning up ..due to the thermostat inside the fuel cooler

ps also adding electric thermo fans make sure your charging system is up to scratch this can put stress on a worn stator and brushes and testing with a multi meter isn't good enough ... a batt tester that can read amps also engine load starts to rise the harder the alternator is working means more stress on other components
 
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