Fan Switch Temp
Turbo Mini Forums

Hi, got a VW Caddy radiator which is the biggest rad I can get to fit inside my clubby front (cheap and big!), inlets are perfectly positioned as well, but the fan switches meant for it are something like 90+°C on which seems too hot.

I'm sure Vizard etc still say that A series engines run much better cold (like 72°C ish), so doesn't it make sense for the fan to activate at about 80°C?

I'm going to be rallying, and plan to use a 72°C 'stat, with some extra holes drilled in it (I know everyone says run a blanking sleeve thing but engines warm up much better with a stat), and was going to put either one or two electric fans behind the rad, not that they should see much use.

Any advise on the whole thing, temps and fans etc? (Should have said it'll be 1310 NA).

Cheers,
TC

www.topcatcustom.co.uk

I'm putting an 88 stat in and a fan switch that is on at 92, of at 84ish.

From recent reading, ideal temperature is high 80's.

I just thought the 72°C is the stat not running temp, why are you putting an 88 stat in and fan off switch that is lower? Technically the stat will be shut before the fan stops (maybe not quite in practice).

Just found this that should fit, on at 87 off at 82, but maybe too low as could be running all the time http://www.ebay.co.uk/itm/For-Astra-Calibr...1#ht_2353wt_952

www.topcatcustom.co.uk

If the stat shuts, then the engine temp will be maintained until it needs to open again. The rad fan will be cooling the stuff in the rad ready to cool the engine when it gets above 88 again.

I would expect it's swings and round abouts though. I highly doubt an a series engine will maintain an exact engine temp consistently once it is warmed up in the same way a modern car will. My setup is acceptable to me and should keep the balance between ideal temp and fan running times.

Have a look here for fan switches:

http://www.intermotor.co.uk/?p=smpeurope/c...n2fu45i9s9nbob4

helped me identify plenty of switches that would fit my rad.

The temperature of the thermostat is the temperature it starts to open. The thermostat maintains the temperature of the engine. If it overheats with an 88c stat, it will overheat with a 72c stat. so why run the engine so cold?

Unleaded fuel burns more efficiently and completely with engine temperatures above 85c, which is why engines from the late 80's onwards run around 90c on the clock.

I thought I remembered reading in Vizards yellow book that he used 72°C stats, but was a while ago so can't remember all the details.

I know how they work which is why I want to use one instead of a restrictor plate thing that most people seem to tell you to use for competition use.

I just wasn't sure what temperature I would want the fans to come on at, and now I'm not too sure about what stat to use!

Also I've got a huge rad, fans probably won't come on much when on the move but would anyone care to recommend one or two electric fans? Will probably be 10" kenlowe type ones.

www.topcatcustom.co.uk

Its the 74 degree stat you need,

As Steve says,use the 74 deg stat,then maybe 82-85 fan switch.I have an adjustable one,set to about this.It stays on after I shut down for up to 15 mins,but sets up a thermo-syphon movement of coolant to cool the turbo.If I switch it off early I can get localised boiling so I think it's effective.

'Where does the engine go?'

I agree with sprocket, modern fuels need to run hotter,

Cheers guys, thought I was imagining it! Are you sure it's modern "engines" that need to run hotter, not the fuel?

A lot of those fan switches for modern cars don't come on until 120°C!!!

www.topcatcustom.co.uk

Where abouts/ how do you normally fit these? in the radiator bottom hose?

top hose or near the top of the rad as you are concerned about the coolant hitting the rad not leaving it

Is it not for when the water has been through the rad and is not sufficiently cool enough so the fans kick in to cool the water down as it goes through the rad?

if that makes any sense

look on your metro's rad. the fan switch is about 1/5 down from the top of the rad.

No it's to put the fans on when the water is too hot for the rad to expel the heat without more airflow.

The boss on my rad is about 1/5 down on the inlet end of the rad.

I'll look for one that does the high eighties, shouldn't stay on for too long after engine shut down then.

www.topcatcustom.co.uk