Radiator Thermal Switch

[Footer]

I have little driving experience with my 73 TCS but have noticed that when the coolant is up to temperature, the thermal switch is forced out of the radiator housing, as in the picture below.  This goes in with only a friction fit and not much friction at that. 
When I see it like this, my fear is that it will work it's way all the way out, providing quick drainage of the radiator.
I looked the arrangement over in an effort to provide some type of lock down action but didn't come up with any quick solutions.  I could grip the lip of the end tank on the front but the back side is tight against the wheel well.  I haven't tried but am not very optimistic concerning some type of glue or bonding agent.
Is this normal and am I worried about something I don't need to be or is there a solution to this I'm unaware of?

[Grumblebuns]

There have been accounts of the otter switch popping out causing coolant loss over the years. The most simple fix is to wrap safety wire through the fins and across the switch.
How old is your grommet for the switch?

[Footer]

The switch only has about 5 hours on it.  I've been having cooling problems since the motor went back in .  Because of that, it's brought up to temp while idling in the driveway.

[Grumblebuns]

I was referring to the rubber grommet the switch slides into. As the rubber ages, it tends to harden up and may not seal as well.

[Footer]

Sorry I misunderstood. I’m not sure about the grommet. I gave the new switch to the radiator shop to install when they rebuilt it but don’t recall if it contained a new grommet.  My guess is that it did not.  Now, the switch easily slides in and out so I’m inclined to think it’s the old one.  I saved the one that came so I can go back to that to see if it has a grommet as well.

[jbcollier]

Get a new grommet and get the “long” version from an MGB.  They grip better.  They use a long plastic zip-tie through the rad as insurance.

Better, take the rad and get a 22mm x 1.5 nut soldered where hole is.  Now you can use a screw on switch.

[Grumblebuns]

Found this photo in my files, nice simple solution.

[Triton]

i had the same problem with my 73 special. I made a stainless clip that fits under the hose clip directly under the sender and the other end of the clip i made into a fork shape that fits over the sender unit. No more problem's.   Stuart.