Cooling query

[DavidL]

I'm fairly certain my slow speed fan (SSF) isn't working currently. Symptoms are that the gauge increases quite quickly in traffic up to about 105 and then the high speed fan (HSF) kicks in and brings it down.

Now my AC compressor has been removed but the dash switch still operates the slow speed fan so currently at the first sign of traffic I put it on. So far this keeps the gauge no higher than 90 even in traffic and I don't hink the high speed fan has been needed.

Obviously I'm putting the SSF on sooner than the engine would but, in a very around about fashion, I'm wondering why the system allows the temperature to rise that high (HSF is set at 102) when a lower rated SSF would keep the ambient temperature more even?

Are there other temp rated fan switches I wonder or is there a good reason why 100 degrees is ok or advantageous?
Or is there something fundamentally wrong with my cooling system!

 

[chrisg]

David

from your symptoms I would suggest/ recommend that the cause is the three pin (two temperatures = two speeds) radiator switch that is causing the problem.

As per my previous posts, this should kick both the fans in at low speed at 92deg or as you're finding the A/C switch will do it.

If the high speed function is working the temperature switch is working at 102deg, but really needs to come on sooner.

Yours

Chris

 

[JamesO]

I have exactly the same issue, replacing the switch didn't help, I think mines down to a fault in the loom or maybe from removing the aircon. Not really looked into the problem, I just make sure to run the fan on a bit on shutdown if its a little warm.

 

[scam75]

My car does this too. Temp rises quite quickly at a standstill to just below 2nd line then fans kick in and knock it back to just above 1st line. I just accepted this as normal as its been the same in mine since I got it and also in other turbo's I have driven.

I have never seen my fans operate at slow speed, its either fast or off if it's idling while i potter about. I must try the aircon and see if I get this mystical slow speed! [&:]

Edit to add I still have all aircon components.

Stuart

 

[Mike_Pollock]

There is a very large double relay with the aircon, with a lot of wires, so I would think its quite likely that removing it alters the way in which the fans respond.

 

[JamesO]

I may take a look at it this weekend (if its not too cold). I'm guessing its a common fault so will report back. I'm getting bored leaving the ignition on after shutting the car down when hot.

 

[DavidL]

It has never ceased to amaze me that these gauges go up and down like the proverbial yet other cars don't move at all.
Encouraging to hear other people's get warm quickly too.
Anyone else find their gauge goes up a little going uphill and down going down?

 

[Lowtimer]

Never on the move: only when I am stuck in stationary traffic for several minutes.

 

[JamesO]

Mine does fluctuate a fair bit, but I put that down to the lack of low speed fan (unless the aircon button is pushed) and the 968 block having less coolant capacity.

 

[zcacogp]

ORIGINAL: DavidL

Anyone else find their gauge goes up a little going uphill and down going down?

Never seen it being quite that sensitive, but I agree that it does seem to move a lot quite quickly; surprisingly so, given the amount of metal under the bonnet.


Oli.

 

[scam75]

Only get noticeable fluctuation when stationary, same as described by others.

Under moving conditions my car is hottest (just under half on the gauge) when doing about 40/50 mph in 5th gear for a few miles. Once the revs get up a bit (70/80 mph) and I get more airflow to radiator and increased circulation because of higher revs it seems to cool a little and sit just above the first mark. This is with 2 recent stats.

Stuart

 

[DavidL]

I assuming bonnet vents don't really make much difference and are cosmetic?
I quite like 924 turbo vents and I notice WUF has bonnet scoops on the lights etc.
Various bonnet grills available too.
Mine changes most behind a tractor going uphill - slowly. A surprisingly common occurance around here!

 

[Mike_Pollock]

"Mine changes most behind a tractor going uphill - slowly. A surprisingly common occurance around here!"


Thats because of the speed you caught it up at![]

 

[DavidL]

ORIGINAL: A9XXC

"Mine changes most behind a tractor going uphill - slowly. A surprisingly common occurance around here!"


Thats because of the speed you caught it up at![]

[8|][8|]

 

[TTM]

Are the fans supposed to be working at all if the large silver relay is out of order?

ORIGINAL: zcacogp
I agree that it does seem to move a lot quite quickly; surprisingly so, given the amount of metal under the bonnet.

As James said that is because the 2.7/S2/968 block contains half as less coolant as the 2.5 block.

 

[Mike_Pollock]

If you take the the big relay out, both the fans stop - its the best way of stopping the fans when the temp sensor goes wrong.

Easiest way I found anyway!