MK II 1962 What is the item in the center of the photo, just above the hose? It is triangular in shape and is bolted down with 3 bolts and has one electrical lead to it.

 

It's a coolant temperature transmitter. I'm not sure if its for switching the starting carburettor, or for the dash display.

 

That is the Otter switch to control the automatic enrichment device (choke).

 

This one is for the dash display.

 

Thanks for the responses. I am just getting back acquainted with my car after 30 years in storage! The bolts had rusted out on this and could not find the part in any of the various companies parts catalogues. I am not a mechanic by any means but am enjoying going over the car to see if I can get it running again.

 

As stated this is the Otter switch. The wire that connects to it is a live wire that comes from one of the terminals on the AED or Choke. The otter switch is a bimetal switch which when the engine is cold allows the live wire to go to earth creating the circuit that allows the AED to work. As the engine warms up the bimetal bar in the Otter switch opens up disconnecting the root to earth and the AED then switches off. If the Otter switch has not been used for a long time it can stop working leaving the switch either open so the AED does not work or closed so the AED is always on. A lot of us have put an extra inline switch in to this circuit allowing us to turn the AED/Choke on or off from the dash. I used a second rear window heater switch which has a warning light and looks period so I can turn the AED on or off but I have also left the Otter switch in place.

 

It's for the water temp gauge on the dashboard, Jaguar part number C15472

 

On a MK1 or MK2 a good hiding place for manual switch to replace the otter switch is immediately above the bonnet release knob. A simple pull on push off switch can be mounted on the plate supporting the release knob. This is quite unobtrusive.
Bill Mac
MK1
MK2
S3XJ6
X300
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I have a follow up question. One of the bolts broke off. A portion of the bolt is sticking out but before I try to remove it I was wondering if that is a copper insert that can be removed (see picture) that would expose more of the broken bolt making it easier to grip.

Ray

 

That is part of the switch--You have taken the switch apart and yes it should come out and that will expose more of the bolt. Try heat and go easy. It should come out.

 

Complete:



Dismantled:

 

Be careful when removing the bolt as you have a steel bolt in an aluminium threaded hole. The two metals are in compatible and have a tendency top weld themselves together. Heat is a good option but what will happen is the steel bolt will heat up and expand quicker than the alloy. So use heat which will break the tie between the steel and alloy but then let the bolt cool down before you try to remove it. A good tip I was told once was to use a wax candle. Heat the area up and then melt the wax candle over the bolt. The wax makes its way down the thread as the bolt cools and then lubricates the thread when you try to remove it.

 

Success! Thanks for all the advice. Was able to gently lift the base of the switch out and then remove the broken bolt. Will now need to find a replacement bolt. Should their be a gasket? The picture that Glyn provided showed a gasket but I did not find one?

Ray

 

If there was no gasket, then that's probably why the bolt was seized, coolant was allowed to get into the thread, odd why there wasn't one.
I went to my local auto parts store and bought some cork gasket and made my own.

There must have been some sort of sealant, otherwise it surely would leak.

However there is no gasket between the Otter switch itself and the copper housing _ doesn't need one.

 

Yes there must be a gasket between the complete switch & the manifold.

 

Otter switch cleaned, bolt replaced and gasket installed!



Ray

 

I've used the original choke lever from the 2.4 dash I took the power from the warning light. It works well!

 

RAY
I didn't twig that this was originally a 2.4 which was converted. The use of the 2.4 choke light switching to power the starting carby is very smart. I wish I had thought of it!
I have a 2.4 with the upgraded 3.4 manifold and HD6 carbies. I think I might follow your lead. At the moment it has a hidden switch mounted beside the bonnet release.
Bill Mac
MK1
MK2
XJ6S3
X300
Previous 14 other Jags MK5 to X308.

 

Bill

Mine is a 3.4. In the response from “MK 2 1962” he references how he addressed it in his 2.4. I can’t take the credit for a great idea!

Ray