Electric Fan...Suck or Blow

[follman]

Hi all

I had owned my Stag for nearly 10 years with no over heating problems. However you know when you are stuck in traffic on a really hot summers day (yes think back we do get them) you are sitting sweating your 'sox' off with one eye fixed to the temperature guage.....this is when mine creeps up over halfway........so I end up turning the heater on! Anyway I purchase a brand new 2001 model Pacet fan which I have fitted using that great article in the club mag a few months ago.

To test the efficency I decided to let the car idle in the sun over the weekend just gone, for about 10 minutes.......temperature gauge gets To halfway, I turn on the fan which is mounted directly on the rad vanes on the front using the quick ties supplied, set to blow. TEMPERATURE GUAGE DID NOT MOVE.

Should I have set the fan to suck thus creating airflow, it seem to me that when staionary one fan is blowing against the other?

Any thoughts guys........I was expecting the temp gauge to drop?

cheers
Simon

[martin]

Hi Simon, if the Pacet is in fact blowing, it's aiding the viscous, not acting against it. It might be that it is stopping the temp from getting higher. One point worth mentioning, half way up the useless Stag gauge is not hot ! The difference between half way, and the start of the red, is about 5c, next time you get worried, open the bonnet, if she's overheating, there is a distinct smell of "hot", it's quite recognisable. I've got a 16" Pacet on a variable thermo switch, and a capilliary temp gauge, it all works fine. I think what you've got is Stag paranoia we all get it, I think it might be a requirement of ownership Enjoy, Martin.

[Westfaling]

Simon
Obviously the engine fans sucks and your fan in front of the rad blows so they should not be fighting each other.As long as your temp doesn't continue to rise I wouldn't worry. Once you get mobile and the engine fan speeds up plus the ram air effect of moving the temp should come down.
Nick

[singapore stag]

The engine fan blows, and not suck, doesn't it?


Sukh.

[V Mad]

If the engine fan did blow that would really suck. I mean any fan that works in the opposite direction of the normal airflow sucks doesnt it. The standard vicous fan sucks, so that doesnt suck, its cool eh?

(tee hee...)

[jakesmig]

Given the joice I always preferred a blow.
You say the temp guage didn't move, soonds like you've got a result. Could be your engine was sitting on or about the opening point for your thermostat, if it was it doesn't matter how good a blow you're getting, relief will be an evasive thing.
Also bear in mind that to get an engine to idle slowly the ignition is retarded, and a retarded engine tends to heat up the top end, particularly the exhaust valves, which increases the heat you have to dissipate.
I don't have a mechanical fan,and have my electric fan set to go on at 98 and off at 92, when it klicks in it holds the temperature steady for a couple of minutes then drops the temperature over 2 /3 minutes then goes off again. If I programme in 2 - 3 degrees of ignition advance at idle the temperature takes longer to rise and less time to cool, however the idle is not as good, so I live with the slightly hotter running engine.
My engine is EFI so I control everything through a programable ECU, so I can see, and adjust, everything through the laptop, temperatures ignition advance etc ( I appreciate i'm an RV8 heathen, but whatever floats your boat).
I have to point out that 88c is barely halfway up my temp guage and when the fan klicks in at 98 the needle on the guage ( a combined oil / water temp cappiliary item) is well over half way up.
I suspect you have a well catered for car and that your anxieties are unfounded. If you have concerns, try slightly increasing your idle speed which may cause your vacume control to advance the timing slightly, may help.
Rgds,
John.

[Mark S]

Fans are either designed to pull or blow. There is no room to fit a large puller fan behind the rad due to the crank pulley so you need a blower front mounted if you want to go the electric route. Fan blades are designed to rotate one way only, so to convert a puller to a blower the blades have to be turned over as well as the motor direction reversed. Can you do this on a Pacet?

Is your viscous coupling ok? I fitted one of the Land Rover ones which are VERY stiff and the temp needle has never risen above the E on the gauge since (82deg stat).

[follman]

Fans are either designed to pull or blow. There is no room to fit a large puller fan behind the rad due to the crank pulley so you need a blower front mounted if you want to go the electric route. Fan blades are designed to rotate one way only, so to convert a puller to a blower the blades have to be turned over as well as the motor direction reversed. Can you do this on a Pacet?

Is your viscous coupling ok? I fitted one of the Land Rover ones which are VERY stiff and the temp needle has never risen above the E on the gauge since (82deg stat).

Thanks for all coments

I forgot to mention that my viscous coupling does not work, its bolted though so its spins as fast as the engine. A stag specilist did this many years ago!

Probabley makes the car go faster as I am getting sucked along at 70 mph!!

I will do a longer test when we get another hot day so prabley in few weeks with any luck.

cheers Simon

[V Mad]

Simon, the reason your temperature gauge did not show a lower reading when you fitted the extra fan could be that the thermostat was kicking in to prevent overcooling. The job of the themostat is to switch off the coolant flow when the temperature goes below its set value.

That doesnt mean that the extra fan is not doing its job. If it is the correct type designed to fit in fornt of the rad (ie to push air through the rad) then it will surely help when you need extra cooling.

[DJT]

I forgot to mention that my viscous coupling does not work, its bolted though so its spins as fast as the engine. A stag specilist did this many years ago!

Mm! I would be interested to know which one
The VC is designed to slip above about 2850 rpm. Fan blades on a fixed VC have been known to bend at high revs and carve a nice hole in the radiator. I guess you are a relatively gentle driver.

Dave

[KOY 23]

Thanks for all coments

I forgot to mention that my viscous coupling does not work, its bolted though so its spins as fast as the engine. A stag specilist did this many years ago!


cheers Simon

Hello Simon.

The dreaded words!!

You should replace the coupling ASAP, before an errant blade takes out the rad, bonnet or someone looking under the bonnet!!

Bob Heritage had some good couplings for sale, worth contacting him.

John.

[follman]

Thanks for the help chaps

I don't always drive gently...I did manage to blow the water pump at about 80, which took out the jackshaft...maybe this was not helped by the lack of a viscous coupling?, other than that no problems in 10 years!!!

[follman]

Thanks John, Bob has contacted me.

cheers

Simon