My mate wants me to wire up a thermo fan to his car so it's continually running (when ignition on), for some reason this doesn't sound like a fantastic idea to me.
Can a thermo fan overheat and shit itself if its constantly running? It will be my old Davies Craig 14" which is probably 4 years old by now.
Continuously running thermo fan?
Started by
_Terrible One_
, Apr 21 2009 05:44 PM
38 replies to this topic
#2
View GaragePosted 21 April 2009 - 05:45 PM
It should be ok as long as it doesn't interfere with the passive air flow.
#3
_426_
_426_
-
- Guests
Posted 21 April 2009 - 06:01 PM
Engines have an optimum running temperature range, this is why the thermostat kick the fan in and out during opperation. Running a hard wired thermo fan can prevent the engine from reaching that range.
Basicly it can be like constantly running a cold engine... not good.
Plus, if the engine can still reach thw optimum temperature range, it will take longer for the engine to warm up in the morning.
In short, the fan motor will be ok but the car motor will suffer.
Basicly it can be like constantly running a cold engine... not good.
Plus, if the engine can still reach thw optimum temperature range, it will take longer for the engine to warm up in the morning.
In short, the fan motor will be ok but the car motor will suffer.
#4
_LHoon_
_LHoon_
-
- Guests
Posted 21 April 2009 - 06:16 PM
Not always true. Fan motors are not always rated for continuous use and can overheat or even catch alight under certain conditions. It often depends on what kind of bearing or bush the manufacturer has used for the motor shaft. Its probably OK, but I would check with Davis Craig.In short, the fan motor will be ok
Should also mention that if its a brushed motor, it will also wear out much quicker than intended.
Also, the engine will be ok because the thermostat is there to stop the coolant flow during the warm up phase. Whether or not the fan is running will not make any difference. Different story of course if you've removed the thermostat.
Edited by LHoon, 21 April 2009 - 06:18 PM.
#5
_426_
_426_
-
- Guests
Posted 21 April 2009 - 06:59 PM
^ Yes true, its not good for the fan to run contantly, my point was the main issue would be the engines life. Cheaper and easier to replace a fan than a good engine.
Good point on the thermostat on warm-up. Be mindfull that the water in the engine will heat up, but as the thermostat tries to open the constant operation of the thermofan will quickly affect the over-all system temp.
Theres a big difference is ambient temperature cooling and forced cooling. Thermostats are not designed to operate in constant forced cooled conditions.
Good point on the thermostat on warm-up. Be mindfull that the water in the engine will heat up, but as the thermostat tries to open the constant operation of the thermofan will quickly affect the over-all system temp.
Theres a big difference is ambient temperature cooling and forced cooling. Thermostats are not designed to operate in constant forced cooled conditions.
Edited by 426, 21 April 2009 - 07:03 PM.
#6
REDA9X
-
- Inactive
-
- 0 posts
Removed
- Joined: 08-November 05
Posted 21 April 2009 - 07:03 PM
Silly idea, continuous drain on the charging system too, and the fan will wear out quicker. There is no need to have it running when the car has forward motion too. You can get them with adjustable thermostats, or you can also wire in a switch so he can turn it on when he wants, say when he knows he will be in traffic.
#7
_SS Hatchback_
_SS Hatchback_
-
- Guests
Posted 21 April 2009 - 08:25 PM
I wouldnt run it constantly , like was mentioned before constant drain on the charging system pulling around 15 to 20 amps when its not really needed, brushes on the fan motor wear out quicker like the ones on my au fans which i had to replace one motor. Use the temp switch as reda9x mentioned , dont do it on a switch to manually turn it on and off either as you may forget to turn it on at times and its just a pain in the ass to keep an eye on it all the time.
In short use a relay and a temp switch.
In short use a relay and a temp switch.
#8
_426_
_426_
-
- Guests
Posted 22 April 2009 - 04:49 PM
In short use a relay and a temp switch.
X2
You could even run a digital unit and custom set the hysteresis
#9
_The Baron_
_The Baron_
-
- Guests
Posted 23 April 2009 - 10:25 AM
Have you got any info on the digital unit?
ie cost? etc.
The switch in the radiator is perfect for mine and I also have the override too.
ie cost? etc.
The switch in the radiator is perfect for mine and I also have the override too.
#11
_@milco@_
_@milco@_
-
- Guests
Posted 23 April 2009 - 11:44 AM
mmm i like that idea, only prob i think would be finding a place to put the sender...
#13
_torbirdie_
_torbirdie_
-
- Guests
Posted 06 May 2009 - 01:23 AM
^ Yes true, its not good for the fan to run contantly, my point was the main issue would be the engines life. Cheaper and easier to replace a fan than a good engine.
Good point on the thermostat on warm-up. Be mindfull that the water in the engine will heat up, but as the thermostat tries to open the constant operation of the thermofan will quickly affect the over-all system temp.
Theres a big difference is ambient temperature cooling and forced cooling. Thermostats are not designed to operate in constant forced cooled conditions.
I agree its cheaper to replace a fan than an engine, but no that doesnt support the rest of your post!
Whether the electric fan is run constantly or not is going to have negligble consequences on engine life. The added airflow over the motor while it is warming up is hardly going to be significant compared to either what it normally experiences from an engine fan or from the normal ram air of moving forwards.
As has been explained to you, the thermostat is the main device which allows the car to warm up quickly, electric fans dont get in the way of making these work any more than the air that comes through from moving forwards.
I agree with the other posters, electric fans aren't designed for constant use and if a constant air flow is needed there is little point to replacing the engine fan with one.
Re the jaycar kit? kit + sender = $100 + construct kit, there are cheaper options.
Edited by torbirdie, 06 May 2009 - 01:27 AM.
#14
_426_
_426_
-
- Guests
Posted 06 May 2009 - 06:49 PM
Nowhere did I say air flow from the onto the engine will ... blah blah.
Clearly people are relying on the the thermostat to save to day BUT here's the deal and its quite simple.
An combustion engine uses an intense action to create movment. A series of explosions in a confined area that is powerfull enough to move item of conciderable weight at conciderable speeds. It requires a delcate balance and a sybiotic relationship between ALL components. Too much or too little will have an affect.
Go through any maintannce manual and it will give optimum settings for maintaining an engine. These settings keep the engine within the required parameters of optimum operation.
Lubrication, timing, temperature, bolts tentions, preasures... all to keep the intence action within the controlled parameters.
Each compoinent is designed to work WITHIN these set parameters.
Adding a CTF will affect the equation, be it directly or indirectly.
eg. you have now put the coolant outside the optimum temerature range. Sure the thermostat will maintain optimum temparatue range, however it will be doing it not quite as it was designed to do it. This may affect flow with in the head, therefore create uneven temperature through the engine... etc...
So even though it may be a small alteration, you have just created a weak point that wasn't there and has no need to be there.
Clearly people are relying on the the thermostat to save to day BUT here's the deal and its quite simple.
An combustion engine uses an intense action to create movment. A series of explosions in a confined area that is powerfull enough to move item of conciderable weight at conciderable speeds. It requires a delcate balance and a sybiotic relationship between ALL components. Too much or too little will have an affect.
Go through any maintannce manual and it will give optimum settings for maintaining an engine. These settings keep the engine within the required parameters of optimum operation.
Lubrication, timing, temperature, bolts tentions, preasures... all to keep the intence action within the controlled parameters.
Each compoinent is designed to work WITHIN these set parameters.
Adding a CTF will affect the equation, be it directly or indirectly.
eg. you have now put the coolant outside the optimum temerature range. Sure the thermostat will maintain optimum temparatue range, however it will be doing it not quite as it was designed to do it. This may affect flow with in the head, therefore create uneven temperature through the engine... etc...
So even though it may be a small alteration, you have just created a weak point that wasn't there and has no need to be there.
Re the jaycar kit? kit + sender = $100 + construct kit, there are cheaper options.
#15
_Squarepants_
_Squarepants_
-
- Guests
Posted 06 May 2009 - 06:52 PM
Solid mount fan saps a minor amount of HP.
Thermo running constantly will wear out faster and places load on alternator which will sap minor amount of HP.
Why not use a thermo switch with an over-ride manual switch. In my opinion, this is the best compromise. Might cost a couple more bucks but is worth the investment.
Running it constantly is just laziness IMO.
Thermo running constantly will wear out faster and places load on alternator which will sap minor amount of HP.
Why not use a thermo switch with an over-ride manual switch. In my opinion, this is the best compromise. Might cost a couple more bucks but is worth the investment.
Running it constantly is just laziness IMO.
#16
Posted 06 May 2009 - 08:30 PM
Come again? There is constant air flow through the radiator if the car is moving, do you mean to say that by using the wrong combination of idle and various road speeds one might cause engine temperature problems...?Sure the thermostat will maintain optimum temparatue range, however it will be doing it not quite as it was designed to do it. This may affect flow with in the head, therefore create uneven temperature through the engine...
#17
_Squarepants_
_Squarepants_
-
- Guests
Posted 06 May 2009 - 09:13 PM
Road speed shouldn't matter. A standard car should keep a constant reasonable temp if sitting still and idling.
Thermostat will open variably to allow enough water flow (and solid mount fan will provide enough air flow) to keep the car at that reasonable temp.
I think we're getting a little off topic now...
Thermostat will open variably to allow enough water flow (and solid mount fan will provide enough air flow) to keep the car at that reasonable temp.
I think we're getting a little off topic now...
#18
Posted 06 May 2009 - 09:38 PM
I think its on topic...? From what I understood, 426 was saying that running a fan continuously will affect operating temp. As many above have posted, this is not so as the (water) thermostat controls the temp - my point was that such a theory is blown out of the water if you consider the cooling offered by air flow when the car is moving.
#20
_Pallbag_
_Pallbag_
-
- Guests
Posted 06 May 2009 - 10:05 PM
What is the optimum temp for a holden V8 ? And what is too extreme/hot before things can go wrong ?
#21
_Squarepants_
_Squarepants_
-
- Guests
Posted 06 May 2009 - 11:46 PM
A street car is not always moving though. It is sometimes caught in traffic jams, or as I found yesterday, caught on a blind crest behind a stalled truck that just couldn't get going again for some reason or other.I think its on topic...? From what I understood, 426 was saying that running a fan continuously will affect operating temp. As many above have posted, this is not so as the (water) thermostat controls the temp - my point was that such a theory is blown out of the water if you consider the cooling offered by air flow when the car is moving.
This is why I think a thermo-fan should be on a thermo switch with an over-ride switch. If every thing is cold, you get nothing, so the engine can warm up properly. When you know you'll be sitting at idle for a while you can turn it on manually to keep things cool, when you're moving at slow speeds the thermo switch kicks in, then when you're at normal road speeds the "ram air" flow should be sufficient to control the temp.
I think we're arguing the same point here. An engine should only have as much air flow as it needs, no more, no less. A solid mount fan only spins as fast as the engine does, compensating the airflow. Therefore, having constant full airflow will effect the engine in a way it wasn't designed to be effected.
I think we're getting at the same point, anyway. If you disagree with this, 426 (or 76LX for that matter), speak up, I'd like to know more behind your theory, as you both definately seem to know what you're talking about.
#22
_nial8r_
_nial8r_
-
- Guests
Posted 07 May 2009 - 07:46 AM
wel its all been pretty much said " not a good idea m8 " i dont see the drama in installin in right the first time then all you really have to do is set the cut in/ cut out temps and there will be no drain on the charge system, and the thermostat wil operate correctly and then everyone is happy, thats my early morning 2 cents worth !!!
#23
Posted 07 May 2009 - 08:27 AM
Yes we are, I didn't mean in response to your postI think we're arguing the same point here.
#24
_torbirdie_
_torbirdie_
-
- Guests
Posted 07 May 2009 - 11:51 AM
I think we're arguing the same point here. An engine should only have as much air flow as it needs, no more, no less. A solid mount fan only spins as fast as the engine does, compensating the airflow. Therefore, having constant full airflow will effect the engine in a way it wasn't designed to be effected.
Sorry disagree entirely. Have a think about it, a thermostat wouldnt be needed if we could somehow always have the optimium amount of air going through the radiator.
For 99.99% of our driving we have more air going through the radiator than is necessary to keep the engine at operating temp, for example cruising at 100km/h and OC ambient, little of the airflow is needed to keep the engine within operating temp. Hopefully no-one here is going to argue that the 95% of air that isnt needed will cause engine damage?
The thermostat restricts the cooling so the motor stays at operating temp, this happens for 99.9% of the time regardless of whether we have an electric fan that is permanently on or an engine fan or if we are going 100km/h. An alternative to thermostats used to be to put blinds/shutters on the radiator.
There are extreme situations where too much airflow can be a problem. In very cold environments, ie - 40C, because of the very slow flow of coolant through the radiator, the coolant rentering the motor can be very cool and cause shock problems as well as not all of the motor reaching the temp it should due to the cold air passing over it. You will see big rigs in colder climates with covers over 2/3 of the radiator etc
In summary, running electric fans when they arent needed will hurt the hip pocket eventually, but no it wont affect have a critical effect on engine operation. There will be a small difference in how long it takes to get to operating temperature due to the cooling of the engines external surfaces etc, but we are talking seconds.
Edited by torbirdie, 07 May 2009 - 12:04 PM.
#25
Posted 07 May 2009 - 12:29 PM
We used to have a thermofan switch on our open wheeled race car, but that was only to prevent overheating from heat soak from the block when stationary. Only works when you have electric water pumps though... Bit useless for our torry needs...
1 user(s) are reading this topic
0 members, 1 guests, 0 anonymous users
