Thermo Fan or Fixed blade?

[Ol_Girl_58]

Hi all,

Once I get the FC up to (driveable) standard, I've decided that I want to drive it to uni every now and again. Upon thinking this, I wondered how it would cope in peak hour traffic of a morning and evening.

That got me thinking about installing a thermo fan. Surely there are many advantages of a thermo fan over a fixed blade fan. I was wondering if you could run both? Would that keep it running cool? The car is running a VB Commodore radiator (yuck), and a 6 blade metal fan. I was thinking about deleting the metal fan and purchasing a VB-VK plastic blade fan.

After all of that drivel, my question is, can you run both a thermo and fixed blade fan? What are the main advantages of a thermo fan over a fixed blade?

is it more efficient to run a larger thermo fan or two smaller thermo fans?

Thanks,

Josh

[Glenn 'Stinky' Stankevicius]

1. You can run both, but having a fan on the motor will restrict you to a push-type fan in front of the radiator.

2. The most efficient set-up would be a large single fan, unless you have a particulary long and skinny radiator, in that case two smalls would be better.

(Dis)Advantages
- Electric fans can be thermostat or manually controlled
- Electric fans take no direct engine power to run, if you delete the motor fan you may get a bit more power.
- Electric fans only run at one speed.
- Fans are really only useful at the stop lights and low speeds, once the car is up to speed that aren't that important.

[FC-V8]

Josh
          I wouldn't think there would be that much if any peak hour traffic in tazzie to worry about the FC overheating.

Glenn

[Ol_Girl_58]

Glenn,

Trust me, at 7.30/8 am in the morning, when buses and parents are taking their kiddies to school, the roads can be fairly congested. The same at about 4.30/5 pm.

I have a bit of a problem in my other car, my trusty Telstar, that when it sits in traffic it heats up pretty quickly. There's a thermo up front. Had it checked out 3 times, once by a mechanic, once an auto electrician, and also a radiator shop, who all said things were fine. In the summer it gets pretty bad. The thermo starts to whirr and vibrate, it gets pretty loud.

If this happens to the Telstar, I thought it would happen for sure on the FC.  

Street Machine published an article a few years back on thermos, recommending them over a fixed blade, as fixed blades suck power from the motor. That interested me somewhat.

Is it just as easy to replace the metal 6 blade fan I have now with a plastic Commodore item? I've been told they spread air more efficiently than the aftermarket that's on the car now.

Cheers,

Josh

[TorqueFC]

personally we have always wanted to run a fixed blade and a thermo, as taking the engine fan off and putting a thermo on isnt really doing as much as you can regarding cooling, personally id run either one thermo and one engine fan, or two thermos

as on our fc, we run 2 twin thermos on the outside and 2 on the inside, but on a grey one thermo with the engine fan owuld be fine

[Fast_Eddie]

You would be better off with an overflow tank as a starting point.

You may also have some other fundamental problems with your cooling system, so a back flush, replacement of thermostat, review of the placement of the auto trans cooler (if fitted), ensuring that you have the correct pressure radiator cap, and the use of a proper coolant should probably be higher on your agenda than a supplimentary fan.

[Ol_Girl_58]

Fast Eddie,

The car is a four speed. I bought the radiator for the FC brand new about 7 months ago. There is a functional overflow tank, the thermostat is about two years old, the radiator cap is stock a Commodore item.  

unfortunately it still likes to heat up.

Should coolant be flushed out regularly and replaced? I don't take the car out regularly (so far once this year). I didn't even know about correct pressure caps!

[RET]

personally we have always wanted to run a fixed blade and a thermo, as taking the engine fan off and putting a thermo on isnt really doing as much as you can regarding cooling, personally id run either one thermo and one engine fan, or two thermos

as on our fc, we run 2 twin thermos on the outside and 2 on the inside, but on a grey one thermo with the engine fan owuld be fine

That sounds very strange indeed.

Modern cars have thermo/clutch fans, not fixed fans, which should tell you something.  Perversely, a fixed fan is counter-productive over about 40 MPH, and actually impedes the air-flow to the motor.  They are really only for cooling at low speeds, or idling in traffic etc.

There's some bloody good reading on the topic to be found here.

cheers
RET

[Glenn 'Stinky' Stankevicius]

AFAIK there are basically two types of radiator caps, one for overflow tanks and not.

Coolant raises the boiling point of the radiator mixture, but decreases the cooling capability of the mix. I use rust inhibitor and clean water in all my cars, the only overheating problems have been mechanical (busted belts and an old radiator).

I don't know what sort of motor you are trying to cool, but a VB Commodore radiator should be able to keep up with a Std to Mild red six.

Does the car over-heat or does the temp just rise in the traffic and stay stable after that?

[Ol_Girl_58]

It's a fairly warm 192 Red motor, previously ran nitrous, before that ran triple carbs (has awful recess in fire wall). It heats up in slow moving traffic/at the lights traffic very quickly. The temp rises fairly high, and on take off, it becomes sluggish.  

[customFC]

Look at getting a new radiator made up with extra cooling capability. I run a HR radiator with 30% more fins, but you could also go with an extra row added. I run stock 202 and it will sit in traffic all day without boiling. The car recently started to run a bit hot and I had it flushed, new coolant added and replaced the thermostat. My radiator guy said it appeared the thermostat was not opening all the way.
Try Aussie Desert Cooler for a simple mail order option.
They can be contacted at 350 Murray Rd Preston Vic 3072. Ph 03 9470 4449.
Regards
Alex

[TorqueFC]

i am not completely sure on this topic, but i believe if you are running a thermo or two it is better off if you use a crossflow radiator as the water takes longer to get from top to bottom which means that the thermo will be making the water more cooler

[Grah]

Josh,

I have a warmish 192 in "Doris" FC Ute, it runs a thermo fan and has given me NO problems driving around Hobart and or Tassie. your welcome to come and have a look? The engine is currently in variing degrees of strip down at the moment so you can see it in all its naked ness!

Grah.

[Jockster]

I run a warm 192 in my Fc with a standard, but new radiator and a 18 inch thermo fan. I run a product in the cooling system called "wetta water"which was advertised in cruising magazine. On a 42 degree summers day, on a slow car club cruise around town the temperature stayed on 92 degrees C all day. Prior to adding the wetta water product on a hot day it would run to about 98 - 100 degrees.
Cheers
Jock

[NO NAME]

I have a 192 with no engine fan as the engine fan kept getting caught in the radiator, I run two fans on the front with seperate switches, I have only needed the second fan at the summernats and in burnout comps.
some of the serious burnout guys use a flex fan on the engine, thermos on the front, big aluminium radiator and water atomisers.
however if you are just driving to uni you shouldnt need to much unless you will be doing lots of linelockers on the way.
my car travels on the M4 in peak hour wich is nearly as slow as cruising at the summernats, one year a guy with a EK at the summernats told me that he removed the temp guage becuase it stressed him out and after that he had no more problems.
thermo fans dont have as much cooling power as a engine fan the same size but they rob less power from the motor, they would put a little more load on the alternator but.
try to use efficient modern thermos, I dont know if late model falcon ones will fit but they might be woth looking into, they come as two fans in a single shroud and are supposed to be quite effective.