Picked up TCS

[Grumblebuns]

Take the rad out and solder a 22 mm x 1.5 nut to it.  Lots of rad fan switches available in that size.  No more worries and a greater choice of on/off temps.

That will probably be my next step if my home made retaining clip doesn't work.

Peter, how is the clip secured to the radiator? It appears that the clip fits between the grommet and the radiator.

[EuropaTC]

MGBs seemed to have similar problems (or concerns ?) with otter switches going AWOL. There is a clip with that design, I think you push it on first around the rubber seal and then assemble the otter switch. Which isn't helpful if you've already filled the radiator !  But it's this sort of thing ;  http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=28986#top

Similar designs used on the early Esprit and SJS in the UK also list the clip.  I can't confirm it's exactly the same as the TC although it does look very similar.  Listed as "clip for fan switch" on this page  http://www.sjsportscars.co.uk/index.php?mod=10

Apparently one common trick is to use a zip tie around the clip and radiator panel on MGBs, again I can't comment on how well that works because I've never tried it, but it does seem a reasonable "get you home" type of bodge.

On the cut-in range problem  I have vague memories of 2 or 3 switches being offered with different temperature ranges for hot or cold climates just like the different thermostats that Lotus offered. That could be for the Esprit or even me getting mixed up with other cars (MGB again ?)  but might be worthwhile asking your local specialists.

Brian

(no clip on mine, just assembled clean with lots of silicone sealant to glue it in    )

[jbcollier]

Generally it is not a good idea to use silicone sealant where there is high pressure, hot fluids -- especially coolant.  It can result in the silicone to lose its bond, become slippery and allow the gasket/sensor to be more easily pushed out.  Not quite sure why coolant reacts with the silicone more than oil does but I have seen it quite a few times.

Not a big fan of the MGB style rad fan switch.  If you are sticking with it, make sure you get the "long" rubber seal not the short one.  And always secure it with a good quality zip-tie round the rad tank.  Unfortunately this will not be as effective on a Europa rad as it is so much thicker.

[pboedker]

Yes, the clip fits between the grommet and the radiator. And since the grommet does not move, the clip - and more important the switch - don't either. 

[jbcollier]

I have seen the grommet (with the switch and the clip) "move", quite rapidly.  "Exit pursued by a bear." so to speak.  Don't use a high pressure rad cap.

[EuropaTC]

(part quote)
Not quite sure why coolant reacts with the silicone more than oil does but I have seen it quite a few times.

I think it's down to the correct material for the job (or rather the incorrect material in that case    )   These days there seems to be lots of different formulations which are technically silicones and marketed as such, but with differing properties.  I'm not familiar enough with the chemistry to know the details, but I do have several grades in my workshop with differing application ranges, one of which is specifically for waterpump assemblies.   The material does work, the Elan waterpump has been in since 2010 and the otter switch March 2011 with no  leaks so far. (tempting fate there    )

Without knowing the details in the case you've seen it's not sensible to say "ahh, definitely the wrong stuff" but it does sound like it on first glance. The trouble is silicone is sold for everything from fish tanks and window frames to applications at 200C. Even at our local motor factors there's at least 3 grades sold in almost identical sized tubes so it's easy to pick up the wrong stuff.

At a pure guess from your description of the material going slippery I'd say it's absorbed ethylene glycol or whatever is used as anti-freeze to degrade it. Most soft elastomers absorb water to some extent, but usually not enough to cause problems like that.

Brian

[3929R]

I really like the spring retaining clip but used what I had at hand. Instead of a zip tie, mine is secured by a piece of safety wire through/around the side of the radiator. Wire should last longer than a plastic zip tie, is thinner and thus easier to thread through the radiator, and I think can be twisted as tight or tighter.