marcotuinenburg
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| posted on 11/1/07 at 11:11 PM |
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do i need an on/off button for the fan ?
Hi,
A friend of me told me it is better to put an on/off button on my dash for the fan.
This way i can put my fan on when i'm in traffic and the engine is getting to hot.
Now when i'm thinking about it i don't think it is needed.
Am i correct with this :
When i'm getting in traffic and already would like to start the fan blowing there will no effect off it because the thermoswitch is still closed
and there is only a minimum amount of water going through the radiator.
But when the engine is building up heat the thermoswitch will open by itself and the fan also starts running by itself.
So, is it needed to mount this switch ?
Some advice please,
Thanks, Marco
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JoelP
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| posted on 11/1/07 at 11:15 PM |
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i think it is a good idea myself. You would wire it in parallel to the thermostatic switch so that either could activate the fan. If you are in
traffic on a hot day it can be convinient to start blowing before the temperature rises! However, if you have a big rad and a small engine, you dont
really need to worry. Some rads cant actually keep the engine cool on a hot day, hence you might need to be a little proactive and get the first shot
in!
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Browser
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| posted on 11/1/07 at 11:22 PM |
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I think you might be confusing thermoswitch with thermostat Marco.
When you're stopped in traffic, the thermostat will open to allow the maximum amount of water to circulate around the cooling system. As the car
is not moving ther is no airflow over the radiator to carry the heat away so the rad will get hot. The themoswitch should then sense this and close or
switch on, allowing the fan to run and draw/push air through the radiator, removing the heat from the coolant. If the fan is powerful enough and the
cooling system up to snuff, the coolant should lose enough heat for the thermoswitch to open or switch off, stopping the fan.
What I think your mate is on about is wiring in a switch, mounted on the dash, which is connected in parallel with the wires going to the
thermoswitch. These wires which are connected the the thermoswitch are permanently live, so when the switch loses the fan comes on. If you want to
switch on the fan sooner than the thermoswitch does, you would simply switch your dash-mounted switch 'on', the circuit to and from the
thermoswitch os closed and the fan starts.
I apologise if this seems long-winded and over-simplistic, I don't want to assume any level of knowledge and thus dazzle you with bu*****t
Are you having cooling problems then?
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stevec
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| posted on 11/1/07 at 11:33 PM |
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Put a switch on Marco, you dont have to use it but wiring it after you have finished building will be a pain in the butt.
And as previously said "you can get the first shot in"
Steve.
[Edited on 11/1/07 by stevec]
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RazMan
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| posted on 11/1/07 at 11:38 PM |
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Personally I think an override switch is a bit uneccessary but I suppose it could offer a little reassurance in traffic queues.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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James
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| posted on 11/1/07 at 11:50 PM |
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I've fitted one... 'just in case' but it's actually a waste of time in my opinion.
IMHO better to get appropriately temperature switching thermostat and thermoswitch and use these.
If rad isn't cooling the engine because you're stationary then the thermostat and thermoswitch will regulate it.
Bearing in mind the engine is most efficient at a certain temperature, if you pre-empt the switch with a manual then all you're likely to do is
cool the water below that which you want the engine to be running.
At the end of the day, the switch is easier to fit now. It's just you don't need it IMO!
Cheers,
James
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"The fight is won or lost far away from witnesses, behind the lines, in the gym and out there on the road, long before I dance under those lights."
- Muhammad Ali
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dmottaway
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| posted on 12/1/07 at 04:02 AM |
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only time I can justify a switch is on a 4 wheel drive truck in deep water. turn the fan off to protect the fan from breaking!
If you suspect you may need one, but are undecided, you could put the wire in place in the harness, but leave it unconnected at both ends. If, in the
future, you decide you need it, the hard part is done. If you never need it, perhaps the wire would come in handy for some other use.
dave
Somewhere, in Texas, a village is missing its idiot.
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Humbug
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| posted on 12/1/07 at 07:01 AM |
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I put in an override switch "just in case" and have never needed it. If I was doing it again, I would either leave it out entirely, or
hide the switch away under the dash somewhere and just leave the essentials on show
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rayroni
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| posted on 12/1/07 at 08:15 AM |
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Can perhaps be used to keep under bonnet temperature down a bit, when stuck in traffic?
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zxrlocost
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| posted on 12/1/07 at 08:28 AM |
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I had one on my r1 Indy and it was a good idea
a bikes fan doesnt come on till about 106'
so when you run hotter anyway as its in a car pulling more weight
seeing it go over the 100 mark a few times automatically concerns you as car engines run a lot cooler
Id say yes
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DarrenW
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| posted on 12/1/07 at 09:34 AM |
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Yes, fit one. Several reasons;
1. Its cheap and easy to do so why not?
2. You can pre-empt a hot moment in the depths of summer and get the first shot in,
3. In winter you can blow a little warm air towards you before the fan has kicked in if you are traffic lights etc (every little helps).
4. Override in case the thermo switch fails.
(OK - i was struggling with reasons when i typed 3)
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02GF74
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| posted on 12/1/07 at 10:02 AM |
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well ther seem to be 2 camps. I'm in the one where it is not needed, especailly if you have a thermostat that can be adjusted for when the fan
kicks in.
Having said that, I have on/off/auto on my LR - off for as someone mention prior to wading, on just for the hell of it.
If you are gonna fit one, do it when you have access and before you have taped up the loom - eve if you don;t use ot, it may ome in handy for
something else.
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marcotuinenburg
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| posted on 12/1/07 at 07:15 PM |
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Thanks for all your reply's.
I decided to wire the fan with a button.
But when the fan starts working the fuelpump reacts on it.
The sound of the fuelpump is changing.
Normally it's going on and off when it's on pressure but when the fan is running the fuelpump is going on and off more quickly.
Is this normall ?
Thanks, Marco
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