Needing advice please.

1984 HE V12

The V12 has a sensor of some sort in the rear of the coolant pipe on the RH engine bank at the other end of the thermostat housing.

My one has been disconnected and I am concerned it may be important?

The pictures show its location and it has a stamp which appears to say ELMWOOD 3000.

Does anyone know what this is supposed to activate or monitor?

Cheers

 

Isn't this the cold start/timer thermal sensor? The one that wastes fuel on startup. I tore mine off and smashed it.

 

Mmmm interesting, Not sure where the plug has gone, but ok sounds good.

 

Holy **** these V12's are thirsty haha!

 

It appears to be part number EAC3762 but I can't pinpoint the exact function. Thumbing thru various old Jaguar parts catalogs it appears that it was used on a variety of different Jaguars over the years but merely described as a "Temperature Switch". It may well have been used for different purposes on different cars/applications...but almost certainly related to emissions control or the notoriously complex vacuum advance control system. The 1981-87 XJS catalog does note "Except USA/Canada/Japan".

The shop manual is a bit vague, illustration-wise, but shows a two-prong electric temp switch as part of the vacuum advance control system on "B-Emission" engines only.

That's where I gave up.....but I'm sure there's more info out there if you have time to keep digging.

The EAC1385 "Thermotime Switch" for the cold start system looks entirely different. Note that the stand-alone cold start system was phased out circa 1983-84....I can never remember exactly. It was problematic; many were intentionally disabled.



EAC3762 Temp switch


EAC1385 Thermotime Switch



Cheers
DD

 

I have the same, and it's connected !
I measured resistance to just 6.8 ohm @17°C
I do not have the cold start injector

 

 

Just found this live advert on Ebay...

https://www.ebay.com/itm/New-Jaguar-...-/202238380205

Appears to be for electric cooling fan.

 

And then I get this!!

Aaaaaaargh

https://www.jagbits.com/product/EAC3762.html

 

No, not on the V12s....at least not our vintage.

The switch for the cooling fan is mounted in the radiator hose housing at the water pump housing. See #12 in the illustration below

https://www.jaguarclassicparts.com/u...pipe-5-3-litre

The '3762' switch might have been used for the cooling fan in other models, however.

Cheers
DD

 

On the v12s with air injection ....the ones I'm familiar with, at least.....item #8 in the illustration below controls the air injection. Specifically, at xxx-temperature this thermo-vac valve opens the air injection switching valve so that output from the air injection is 'dumped' into the air cleaner rather than sent to the air injection tubes.

https://www.jaguarclassicparts.com/u...rom-e-8s-64245

However, on the Series III XJ6 with air injection the '3762' is indeed used to control the air injection switching valve....which, on that car, is electro-vaccum

The first thing to do in identifying the function of the '3762' switch on any particular car, IMO, is to determine which market the car was sold in and which emission system it was built with. Parts vendors listings are not always accurate or complete

Cheers
DD

 

Thanks Doug,

I don't think we had any emission controls back in '84 here in New Zealand, so I am not sure if anything has been removed, bypassed or never connected from factory. Maybe they installed it from factory into the coolant rail and just didn't wire them up for the NZ market? (Would have thought that would have been wasteful though?)

There were no CATS on the exhaust system before I upgraded to the performance exhaust.

Thanks

 

Sweet thanks Doug, The wire had fallen off that one so sorted that and I got my elec fan back running.

 

Take a look here under Emission B: VACUUM IGNITION ADVANCE / AJ6 Engineering

My guess is it's the switch for the 15 min timer.