The V8 Owners Forum -

I ditched the mechanical fan on my SD1 and fitted twin AU Ford Falcon thermo fans that come with their own integral shroud which is easy to cut down to fit the Rover radiator. Pull a massive cfm of air through the radiator and keeps the engine cool even on the hottest summer days. Were originally fitted to 1998-2001 Aussie built 5 litre Ford Falcon V8. Cheap to buy and used / repro examples are easily found on ebay.

http://www.ebay.com.au/sch/i.html;jsess ... ans&_rdc=1

Right this has been a headache,
to sum it all up (pics to follow), we have fitted the cossie cooling fans, still no joy, cut most of the panel work out from the front of the car and now its stable, or we thought,
changed the stat too and in 32C air temp gauge was sat at half way in traffic and the fans were cutting in and out at around 89-92C spot on,

left the car for 15mins came back out fired the car up temp gauge up to 1/4 fans cut in checked laptop temp reading was 75C and the fans stayed on temp struggled to get above 82C,

Have tried 2 different fan switches with the same problem, we have sealed the rad to the intercooler as instructed on here to stop the fans sucking hot air back through the rad, are we getting some sort of heat soak from the intercooler tricking the fan switch to cut in???

How many different triggers do you have working the relay?

Thermostat switch, ms, manual override etc

One of them will have a dodgy earth/ground and hence trip the relay. Normally the earth / ground is switched

Either that or the relay is going duff swap it over for another one to get that ruled out

Ian

Not just use the ecu to control the fan ?

I would suggest a simple otter switch on the outside flow side of the rad, coupled to a manual override toggle switch.

Electronics I don't trust. Eg engine may be hot but rad is cold so why turn on the fans?

Ian

Ian Anderson wrote:I would suggest a simple otter switch on the outside flow side of the rad, coupled to a manual override toggle switch.

Electronics I don't trust. Eg engine may be hot but rad is cold so why turn on the fans?

Ian

If your engine is too hot and the rad is cold....better find out why that stat hasnt opened ! lol

In the scenario described, if it is set up correctly the fans would never be on under those circumstances.

fans are triggered by fan switch, each fan has a relay so rules them out,
ecu does not control the fans as yet but maybe soon

the fan switch is in the rad so its saying the rads hot when the engine temp is only 75C

How are you measuring the engine temp?

Coolant temp sensor via tuner studio

Is the fan switch close to a serious heat source which could be getting overly hot bt heat soak?

Ian

Its where it always has been for tbe last 16yrs lol
Only yhong different has an intercooler in front of the rad and the fans are now on the back

Well you’re experiencing the downside of that big ( not to say huge ) IC that covers the whole cooling area of your radiator . No matter how big you fans are, they will always be restricted by that piece of alloy on the other side of your rad. Not to mention that heat sink effect it has. All these issues are written in the books.
And that all for just a few bhp ( 12’C tempdrop equals 1bhp improvement..read the books)

How to test… get that IC out and bypass the IC with some temporary pipe work and test drive it again. If your engine temps are within limits now you know the cause.

While you drive it this way, read IAT temps to see if you really need that IC. These numbers can be useful to compare.

There was a bloke a while ago on this forum making me very aware of all the downsides of an air to air IC system. Did make me read some more about it. On both my homebuilt boosted applications I fitted an IAT gauge to monitor and decide if I had really benefits of fitting an IC in the system.
One ended up with a water/methanol injection kit. (10psi boost Supercharged)
The other one has an IAT of 45'C max on a hot day so need nothing ( 10 psi boost turbo ).

My SD1 has factory air con and seemed to run at about 100C (on the car gauge) in town. Thermostat is 88C, and rad new. Aux fans constantly cutting in - and this without the AC on, as it is broken. On the open road it dropped back to about 90C
I removed the AC condenser to get it fixed, and the town temp immediately dropped to about 90C. So it was obviously causing a fair old restriction to airflow through the rad.

Coops wrote: left the car for 15mins came back out fired the car up temp gauge up to 1/4 fans cut in checked laptop temp reading was 75C and the fans stayed on temp struggled to get above 82C,

Have tried 2 different fan switches with the same problem, we have sealed the rad to the intercooler as instructed on here to stop the fans sucking hot air back through the rad, are we getting some sort of heat soak from the intercooler tricking the fan switch to cut in???

If the engine struggles to get above 82C then it must be assumed that coolant is flowing around the rad and the fans are doing their job and the rad will be at approx 82C at the top and less at the bottom.
The fan switch is in the rad, so it must be reading <82C (when the intercooler is not doing any work) and should switch off.
I suggest the problem is something to do with the relays/wiring/switch which control the fans. Possibly an earth loop holding the relays on.
Or the 2 switches you have tried in the rad are iffy. It is possible to get switches with different temp ranges. For instance sensors/switches which normally mount on the engine block have a much higher setting.

Regards Denis

I think everyone is getting a bit confused
The car is not overheating if anything is too cold according to the coolant sensor but not the fan switch.
Charger not fitted yet so no need to bridge the cooler pipes
To remove charger everything has to come out. Rad fans etc