TCS radiator question

[rjbaren]

Hello, I am pretty new on this forum.  I bought a basket case TCS 5 speed last December and will be trying to put it back together.  I my quest to lift the body off the frame, which has already been off, I want to lighten the body even more so I removed the radiator and swirl tank and brake boosters.  I took the radiator and tank to a radiator shop and the guy immediately removed the rubber ring from the radiator for the temp sensor for either the gauge or the fan, and handed it back to me and said there should be a locking wire or something to keep the sensor from popping out under pressure.  I didn't see a locking mechanism of any sort.  What is the sensor for?  Can a threaded nut be added and a threaded sensor replace the push in sensor?  Is there a locking mechanism for the push in sensor?
Thanks

[jbcollier]

It's for the rad fan switch.  They did not come with any sort of retention but it is a very good idea to add some.  Myself, I would do as you suggest and solder a threaded bung (nut) for the sensor.  The early Europa rads had a M22 x 1.5 bung.  Lots of fan switches available in this size.

[E Paul]

I do think a retainer of some kind is a good idea, although mine never popped out over 40 plus years. If you are actually trying to save weight get rid of the heavy and probably expensive to repair radiator and get an aluminum one...already has the threaded bung.

[4129R]

One of my radiators had the temperature switch wired in place using copper wire through the radiator fin matrix.

It worked but looked amateur. 

[jbcollier]

A very common, and useful, mod to all rads using those silly push in switches.  It all works well enough when new but the rubber loses it's resilience over time.  Eventually the pressure in the rad is sufficient to push it out.

[BDA]

I use a fan controller that has a temperature sender that slides between the fins of the radiator. It works very well and you can hardly see it.I feel a lot more comfortable with it than the otter switch that came stock. Oddly enough, I might not have heard of a case where the water pressure pushed the otter switch out (which is not at all to say that it doesn't happen). Whether I have or not, I don't like the idea that it could be pushed out!

[jbcollier]

The same switches were used on later MGBs.  Right from the factory some came with the rad fan blades installed backwards.  Those cars had a lot of overheating issues and many otter switches left their homes at high rate of knots.

[rjbaren]

Where do I find a part number for a switch to turn on the electric fan?  The radiator shop has bungs but they are not sorted by size.  So he doesn't know if he has a 22x1.5 bung.  He said, bring in a switch and he will install the proper bung.  Does anyone have a part number or recommendation for a threaded switch and where to get it?

[jbcollier]

Either of these two will work:

https://www.amazon.ca/PORSCHE-Radiator-Thermo-Switch-0-9L-2-7L/dp/B00D0CQBPS/ref=sr_1_3?keywords=vw&qid=1557367747&s=automotive&sr=1-3-catcorr

on at 92°C  off at 87°C

https://www.amazon.ca/PEUGEOT-TALBOT-Radiator-Thermo-0-8L-2-3L/dp/B00D0CQCV6/ref=sr_1_4?keywords=vw&qid=1557367747&s=automotive&sr=1-4-catcorr

on at 95°C  off at 86°C

There are others of course.

[rjbaren]

Thank you for the help and information.  Both switches are not available to ship to my location.  Instead I found a BMW switch # 61 31 1 364 272 available.  91 degree C and I think it was a 14 mm thread and has two spade connectors.  It fits many BMWs from the 70s and 80s.  I ordered this for $18.98 including shipping.   FAE brand.  I 'll keep my fingers crossed that the shop can install it.

[jbcollier]

Rad fan switches have temp setting at which they turn on, and a lower settings at which they turn off.  Is 91°C the "on" or "off" temp?

The advantage of the M22 x 1.5 switches is that they come in a wide range of temps. 82/75 (VW diesel) through to 95/92.  Your chosen switch may only be available in the one setting which may, or may not, be appropriate for your application.

[Certified Lotus]

I bought one of the Chinese aluminum radiators and the bung for the temp sensor is 5/8-16 thread. I have to no avail found a temp sensor with that thread that operates at 195 degrees F on and 185 F off.  Anyone locate one? Even summit racing couldn’t match up an adapter to a 3/8 sensor.

[jbcollier]

There are a number of suppliers of rad fan controllers that use an external probe.  These are often adjustable and may also have a reduced power setting for AC.  Just search for a rad fan controller.

I use one myself as I have AC.  But I have a screw in sensor that provides an override for when the temp hits a certain level.

[GavinT]

Maybe a unit like these:

Davies Craig Mechanical Thermal Switch
12 & 24 Volt

Designed for use with Thermatic® fans and EWP®'s. Senses coolant temperature after it passes through the engine block prior to entering the radiator. Adjustable from 40-100° C (104-212° F). Mounts near the radiator and the stainless steel probe is fitted inside the radiator hose.

[jbcollier]

Some just fit into the fins.