Does anyone know the really correct way to re-ins tall the plastic cover for the cruise control ??? One guy says it goes over the top for puncture protection… And another guy says it goes underneath to protect the rubber from excessive engine heat… 5.3 L Help me out here …
Garry,
The first guy doesn’t know what he is talking about. Attached is a picture of the correctly installed cruise control actuator in my wife’s 1990 XJ-S convertible (5.3L V12 with Marelli ignition) with the heat shield located beneath the bellows.
BTW, I see the cruise control actuator heat shields installed upside down regularly online and also in person.
Paul
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It is a heat shield. It should be down to protect the servo from the heat in the Vee of the engine.
Dang, didn’t know we were supposed to have one of those until now. 
I better check out Superblack’s next time I’m under her hood. 
Paul,
If “Superblack” is a face-lift car then I believe that it will have a very different looking cruise control actuator.
Paul
Well, it has the black rubber bellows-type actuator, but it may be a smaller one, like the one on Superblue, as opposed to the ones I’ve seen on earlier models that look much larger in size … Do the smaller ones also need a “heat shield” though, or are they situated far enough above the top end of the engine to not get “baked”? 
Just forget about heat shields. Remove the insulating mat from the bonnet. It will start to work like a giant heat sink.
Yes, and increase the aging rate of the paint on your bonnet - oh, right , you don’t live in Arizona, Florida or the Southern US States.
One engine failure will compensate your cosmetic concerns.
The lifespan of your bonnet’s paint is nothing in compaison to British sheet metal you Jag is made of. Confirmed:
- 12years without insulation on v12 - no issues with paintwork. In Spain.
- 8 years without insulation on 3.6 - no issues with paintwork in UK. Apart from birdshit
Using brakes will deteriorate your brake pads. Riding your XJS will deteriorate tyres.
This is the biggest pensioner argument I ever heard of 
Yeah, this is what put an ugly mark on my bonnet. Tried a few basic polishing techniques. I’ll suffer the cosmetic blemish until I can get a professional to deal with it.
So in other words, in answer to my earlier post on this subject, I should not mess with (i.e. remove) the insulation blanket? what if I replace it with a piece of that shiny aluminum-looking aftermarket stuff they make for the underside of hoods?
Atty,
Waste of money, why would you do something like that to a classic car…
- Bonnet looks much better without factory insulation
- Bonnet rust less without factory insulation
- Bonnet is more fire-proof without factory insulation
- Bonnet without insulation lowers the temperature in the centre of V
- Bonnet without insulation improves true and only benefit of v12 engine - engine sound
Just for myself, just to acknowledge it… Why every old loaf insists to keep it in the car instead of shoveling it into the garage to keep “genuine” potential for future buyers…?
Sorry, but that “giant heat sink” comment scared the carp out of me … 
Atty,
Your bonnet will get hot anyway, to the same temperature each time you’re riding the car. Just the amount of heat it will transfer will be different. No need to be worry. What you should worry about is the amount of ultraviolet your paint work receives fromt the top, not bottom (UVC) 
Riding in Florida will deteriorate your paint work much faster than in pissing-down Scotland. More rides, more cycles of heat up and cool down. That’s why someone invented car cosmetics like wax - coming with UV filter by default.
Long long time ago, people were burning other people for witchcraft. Some of them were Jag Lovers…