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Duratec coolant temp for fan trigger
se7ensport - 12/3/12 at 09:44 PM

Can anyone confirm the correct coolant running temp for a 2.0 Duratec along with the recommended fan on and off trigger temps?


Thanks
Alex

itsawindupuk - 27/3/12 at 07:51 AM

I'd like to know this too, any takers?

se7ensport - 27/3/12 at 08:21 AM

According to the Caterham handbook the optimum operating temp of the water will be 110c in all engines including the Duratec, as such I have set my fan on temp to 112 and fan off temp at 108.

Once I get it on the road I'll look at the ecu logs to see running temp and frequency of fans coming on.

http://webcache.googleusercontent.com/search?q=cache:YDVmzQFodiwJ:www.caterham.co.uk/assets/html/technical/handbook.pdf+caterham+owners+manual&cd =2&hl=en&ct=clnk&gl=uk

MkIndy7 - 27/3/12 at 08:44 AM

Surely the engine thermostat takes care of the engine running temp?.
The fan on/off temperatures shouldn't be the same otherwise the water in the radiator will be as warm as what's in the engine and thus not have much cooling effect...

Think I've got the standard polo switch in my rad but you can always fit one with 2 on off temperatures from a car with dual stage fans should you wish to have more of a choice easier.

se7ensport - 27/3/12 at 09:12 AM

The thermostat only controls the lower end of the operating temperature range – mine opens at 82degrees. Once it is open the full volume of water begins to circulate through the radiator, this is regulated by either the fans or the air passing through it from driving. In slow moving traffic or on a track the volume of air moving through the radiator can be insufficient, hence the fans require a temperature trigger point at the higher end of the operating range.

MkIndy7 - 27/3/12 at 09:22 AM

quote:
Originally posted by se7ensport
The thermostat only controls the lower end of the operating temperature range – mine opens at 82degrees. Once it is open the full volume of water begins to circulate through the radiator, this is regulated by either the fans or the air passing through it from driving. In slow moving traffic or on a track the volume of air moving through the radiator can be insufficient, hence the fans require a temperature trigger point at the higher end of the operating range.


So that means the water in your engine at running temperature is 82deg..
Thermostat opens to allow coolant to flow, until it gets below 82deg at which point the thermostat closes
Stopping the flow to maintain its running temperature causing the temperature of the water to increase untill it gets to 82deg again until the cycle repeats itself.

If anything your rad fan switch temp wants to be very low then with a hight differential between the on and off temp so there is plenty of cool water availalble to for the engine to cool itself when the thermostat opens.
At the moment is sounds like your engine is heating up the water faster than it can be cooled as the water available to cool itself almost at the same temperature as the engine itself.

Unless I'm really missing the point here..

se7ensport - 27/3/12 at 09:36 AM

I think you are looking at it the wrong way around; the thermostat prevents the operating temp of the engine from dropping below 82degrees rather than exceeding it.

82 degrees is considered to be the minimal operating temp of this engine, the thermostat allows the engine to get up to a sensible operating temperature as fast as possible by limiting the volume of water in circulation to the minimum required to prevent hotspots.

It then has an operating temperature range up to a maximum before overheating will cause engine damage, guessing 130+, but the optimum temp for the engine is 110.

MkIndy7 - 27/3/12 at 10:07 AM

Hmm Definately another way of looking at it, I wonder if any of th Duratec engined Fords have an old fashioned Rad temp switch or if there all ECU driven, if there is one that's probably be the best way around this to ensure the correct operating temperature. (I think ours is an early ST150 lump with an old fashioned thermostat so maybe that would be a likely candidate)

On our guage sencor tapped into the back of the water distribution block last year it'd sit happily at about 90deg and rise to about 98 in traffic, rad fan would come at about 98 and cool it back down to 90deg in about a minuite. Never remember it climbing much above that and it sempt happily enough on the track day but that was in October.
Certainly did plenty of MPG and went well enough but if getting it hotter will get more still for the change of a rad fan switch I'm all for that!

britishtrident - 27/3/12 at 01:02 PM

An 88 degree stat only just starts to open at 88c it will won't be fully open until about 94c . in normal UK use with an 88 degree stat expect the coolant to stabilise around 90-91c.


In the UK use the fan would normally only expected to cut in after prolonged idling. Normally the fan cut in temperature is a degree or two above the thermostat fully open temperature ie an 88 stat needs a 94 to 97 fan cut in temp a 91 degree sat a 97 or 98 degree switch.

Normally the cut-in temperature should be about 4 to 6 degrees higher than the fan off temperature.

It is Ok to use a fan cut in temp above a 100c but it is essential to make 100% your cooling system is free from minor steam leaks under pressure.

The ECU controlled fan on modern Fords is multispeed it will only work flat out about 115c.

[Edited on 27/3/12 by britishtrident]