Replacement Temp/Rad Switch M12 x 1.5mm
Turbo Mini Forums

Hey all

Hoping some of the more electrically minded peeps can help.

Im trying to redo the cooling system on the british open i bought off rob, its got an MG1275 lump with MJ and an MPI rad set-up

The fan switch was in the bottom hose within a hose joiner but it should be in the top hose coming from the hot engine.
Rather than cutting the top hose to put the sender/switch in there i am going to use the sensor position in the sandwich plate which currently has the brown type of sender for the MPI (it is unused)

What im after is a replacement fan/temp switch with a M12mm x 1.5 thread which will do the job, im trying to search online but nobody seems to have done this before? If anyone knows of a temp/rad switch with an M12 thread please let me know!

Gaz

i have mine mounted in the sandwich plate
http://www.gwrmotorsport.com/accessories_SFT1217.html

Have a look here (link courtesy of Rod S sometime ago):

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

They list allsorts of electrical stuff, including fan switches/sensors. Most parts have details like thread size and pitch.

I used it to find the part number I needed then went of to ebay.

thanks lads, wolfie im after a switch rather than the thermistor which is what you've suggested, as i want it to trigger the fan at 95degrees and switch off at 90.

Fan switch should be in the bottom of the rad, or at least half way up

You will most likely find M14 x 1.5 is the smallest switch available (it would be hard to package a switch into a 12mm case).

M14 x 1.5 is another common size used on ECU parts and there would probably be enough metal to re-drill/tap (but beware, it is not the standard M14, you would need the correct metric fine tap).

Otherwise use the existing MPI sender and something like this http://www.maplin.co.uk/temperature-activa...itch-kit-220003
Just using the Maplins one as an example, there are loads on the electronics DIY/hobby market. You might have to add a resistor in parallel or series with the sender to get it working in the right range, nothing more.

Schrödinger's cat - so which one am I ???

I did think about drilling and tapping the sandwich plate out but i think they may use something the right size on a fiat, the autoparts place up the road managed to find me a suitable temp switch the last time so we shall see if they can help?

Have you tried calling Think Automotive?

wil try them out rob, im gonna go to patchway tomorrow and check the parts catalogues! are you back in bris yet?

after looking through the books at patchway the smallest switches are M14 and M16 so im gonna try and get a metric to metric thread convertor.

I cant find anything online that would convert M12 to M14/M16, can someone point me in the right direction or make me one? cant believe its this difficult to find a suitable thread adaptor :(

You will find it difficult becuase the three metric sizes are non-standard. They are not the ISO coarse but special fine sizes.

Also, you are trying to go from small to large. That means a stepped adapter, not a simple bush and even if you made one it is extremely unlikely that the head of an M14 or M16 sensor would fit inside the M12 bit of your adaptor as the internal diameter of the M12 bit would be 9mm or less.

So it would have to be an extended adapter with the sensor head in a stagnant bit nowhere near the coolant flow so it would be very slow to operate, if it operated at all.

Schrödinger's cat - so which one am I ???

hi rod, I know where you are coming from as i want the switch to be as close to the coolant as possible, I do have a manual overide switch so i can keep the fan on, its just me trying to package the wiring more sensibly.

Ive found these online, gonne try the M16 and M22 and see if it works, if not i will cut the top pipe and stick the sensor in there.

(the attachment didnt upload but it shows a steel adaptor) will get pics of the install when complete, thanks

Edited by pickmeup on 24th Jan, 2011.

Is there not enough metal in the housing to redrill/tap it M14 as I suggested earlier ???

I have the required metric fine M14 X 1.5 tap because of all the fuel injection stuff I'm doing.

You can either borrow it (just cover the postage costs) or send me the housing and I'll do it - a 5 minute job.

Just so long as there is enough metal there for 1mm extra on the radius (post up a photo if you are unsure).

Schrödinger's cat - so which one am I ???

I reckon there is enough meat in there to drill and re-tap will measure it tonight and see if its possible, I can get it done at work if need be, thanks for the offer though rod