Fan overide switch versus temp gauge change....

[robstvr]

Was discussing a fan overide switch for a chim with a colleague today. He suggested changing the temperature sensor to one which switches at a lower temp. Never considered it. How come folks go for a new switch instead of a new sensor set lower? Is there a temerature setting at which the engine should not be below? The distant bits of what's left of my memory says something about efficiencies with cool air/hot engine, Rankine cycles, or something. Oh, now head hurts....

[brioss]

I fitted an adjustable Kenlowe fan stat to my S3, you can just turn the knob under the bonnet to have the fan come on early if you wish. It was easy to fit, hardest bit was getting the capilary pipe to seal, recomended.

Here a pacet one

www.demon-tweeks.co.uk/products/ProductDetail.asp?cls=MSPORT&pcode=PCTCF305

>> Edited by brioss on Monday 23 January 22:55

[JonRB]

I had a fan override switch fitted early on in my ownership of my Chimaera 500, the advice at the time being that it would enable me to anticipate potential overheating situations like entering traffic jams, etc.

However, when I started taking my Chimaera to a well-respected independant, his feeling was that an override was like a plaster, ie. treating the symptoms rather than the cause. He suggested a Leven low-temperature kit that consists of a lower temeperature themostat and otter switch (it's kit ECK 2 on the Leven site) and at £25 inc VAT is a bit of a no-brainer really.
I had it fitted, and the fans now kick in much earlier and the car never gets near to overheating. I haven't used the fan override switch since, although it's nice to know it is there if the otter switch or thermostat ever fail so that I can manually enable the fans in order to get me home.

Edit: Sorry, Leven's website seems to redirect that URL back to the main page. You'll need to select "TVR" from the menu on the left, then choose "Engine Cooling Kit" from the 1st drop-down list on the page it takes you to.

>> Edited by JonRB on Monday 23 January 23:04

[greenv8s]

The override switch lets you switch the fans on manually when the otter switch fails (the lower temperature otter is just as likely to fail as the standard part), also with the override you can switch the fans on before the engine has started to heat up in a jam, and get a head start on the problem. Last issue is that with the standard otter switch position in the top hose you need to ensure that the stat opening temperature is below the otter switch temperature otherwise the fans will stay on unnecessarily.

[JonRB]

greenv8s said:

also with the override you can switch the fans on before the engine has started to heat up in a jam, and get a head start on the problem.

Indeed. That was the rationalle behind having the override switch fitted to my car. However, as I mentioned, the lower temperature thermostat and otter switch means that my car never gets anywhere near overheating temperatures even in jams, rendering the switch unneccessary for anything other than emergency use (as you also mentioned).

[shpub]

This whole topic is covered in gory detail in the cooling chapter in the bible.

The fan override switch is really an insurance policy. The otter switches do fail and it is so much easier to flick a switch than to pull over, lift the bonnet, find the switch, remove the leads and then find something to bridge the connection. Especially if yoiu are in traffic/at night/ with someone you wnat to impress etc. BTW a fuse is ideal for the bridge.

Details of how to do it are in the bible as well. Or get the Mod-Wise kit.

Running a lower temp otter switch can be beneficial and most TVR specilialists stock them.

They are seperate complementary options.

[theaxe]

I'm thinking of getting the two-stage kit from modwise. It seems to allow the fans to come on at 1/2 speed for one temp and then full if it goes past another.

This seems to make sense and aparently the 'soft-start' prevents fuse failures.

It can also be rigged up with a manual override and status LEDs.

[Little Nicky]

I got them to fit an override swith before I bought my latest Chim a year last September.

I think it's invaluable

A few years back, I had a pre-facelift model and it overheated on me a couple of times - I fitted the switch, and the feeling of security I had after was definitely worth the hassle. (and it wasn't even that much hassle to be honest).!!

[2 sMoKiN bArReLs]

If the car is working correctly the standard fitment is adequate for all conditions.