I'm not sure what this is. I've looked at Haynes and the ROM without success, probably as I'm not sure where I'm supposed to be looking (nothing under "air cleaner" at any rate). It just sits in a hole in the RH cleaner box ( RH = looking from cabin to front) and looks as if it's suppose to be wedged or fastened or something, but isn't. I'm assuming it's something electrical due to the "12V" label.
Any clue what I'm looking at, and whether this is a problem, would be much appreciated.

Mystery object of great mystery. Front of car to left.




It just sits in there happily. Or perhaps not so happily, which is what concerns me.




It just pulls out - it's just sitting there.

 

It's missing the rubber grommet, no biggie, just get another, you can buy inexpensive grommet sets at most automotive and hardware stores.

https://www.jaguarforums.com/forum/x...ication-88929/

 

Thanks - I'll check the diameter and pick some up today. Much appreciated.

 

Extra Air Valve, Supplemental Air Valve, and perhaps another name which escapes my memory.

It opens to admit more air and thus increase idle speed.

Over the many years there were 2 or 3 somewhat varied schemes for operation but, most typically, it is tied into the a/c compressor circuit.

Cheers
DD

 

So it probably shouldn't be hanging loose, I guess....

 

It also looks as if it was mounted wrongly. The arrow shows the flow of air...

 

So the arrow should point inwards then (into the box)? I think this might be just a matter of clamps, plus a new rubber grommet, so within even my completely kindergarten-level mechanical skills.

 

Actually, looking at Kirby Palm's pic, it appears to be facing the right direction. The arrow points out.
Jaguar V12 Supplementary Air Valve

 

As Doug says it's an additional air valve, purpose is to raise idle speed slightly to compensate for extra load if air conditioning compressor.

Switched by air con it bleeds extra air into manifold .

Others with more experience tell me its function is less needed with later Sanden compressor due to less load

 

As Doug said, it is to increase the tickover speed of the engine when the aircon compressor kicks in, thus preventing a stall. It IS facing the RIGHT way When it opens it takes filtered air from the airbox, bypasses the throttle butterfly and admits it under the throttle body, just inside the butterfly. Inset a new grommet to stop it rattling about and prevent unfiltered air entering the engine.
Greg

 

Thanks very much everyone. Now that I know what it is...

...I have just discovered that the hose leading from it to underneath the exhaust manifold has completed sheered in two. I'm sure it wasn't like that yesterday. I have also lost the cap to the yellow plastic filler opening at the right front of the engine (not sure what it is: it vanishes into the right wing right by the front of the engine bay), so put some tin foil over it to keep anything out, and will get it replaced when I get the car looked at tomorrow.

If it's not that vital, can I drive the car as far as the car repair place (15-20 mins?) with a severed aux. air valve hose, perhaps wrapping the severed ends in tinfoil so they don't rest directly on the engine?

 

I think that the cap is the screenwasher bottle fill tube cap. The fractured rubber pipe between the air valve and the throttle body will increase the idle speed a bit, that is all, no need to do anything to it. But when the pipe is renewed you may have to increase the tickover adjustment as this source if air will be blocked off. This adjustment is made via the famous and notorious Auxiliary Air Valve (another one!) also called the Extra Air Valve and it is on the other bank of the engine at the cabin end of the inlet manifold. Your garage will show you where!


However, there is a warning in this find. You can be 100% sure that ALL the rubber hoses are pretty cooked in the engine bay, and possibly parts of the electrical loom. When you get the radiator cleaned/fixed/renewed, and the thermostats changed, ensure that ALL the other rubber coolant hose are also changed, there are LOTS of them and they are hard to get at. If not, at the worst possible moment one will let go!
Greg

 

Thanks Greg. The shop guy said they had been replacing some hoses when going over the engine prior to handing it over, but I'm not too sure if that really happened or which were replaced. I've checked manually for softness, and didn't see any problems, but clearly missed this one. However, you're right of course, and I will ask the people doing the rad to do the hoses as well.

I see people saying the new black fan is better than the old yellow fan too. Perhaps I should order one from the UK while the pound is low....

 

Just a quick note on this air valve. I replaced mine with the adjustable rpm one like Kirby used in "The Book" . This was a great cheap improvement when rpm and AC working together come into the subject. This is particularly involved when a manual transmission conversion comes into play .
Lawrence

 

Have you got a link or a part number for this useful sounding item, please?
Greg

 

The air is going into the engine, so it is point the correct way. My grommet is also toast, must be a common casualty.

 

You're right, it ismthe right way... I dunno how Imsaw that wrongly...

 

Greg
I'm sure I can get some info on the air valve but may take some time since I'm not at home at this time. I know it was used on older Honda's, Subaru's,or Toyota to increase the rpm when the ac compressor kicked in. I will get back to you .
Lawrence

 

Doing a web search type in Nippondenso 084600-5510 scroll down to V12 supplementary air valve . This part number will only give a picture and great info about the Toyota part I used and the stock "12V" air valve. At some point we will find what model, year & part # this Toyota air valve came with.
Lawrence

 

MINE WAS ALSO...
I think that was the first repair.... and I had a box of assorted grommets so I just found one that fit snug....
they do fall out on occasion and the grommet stays on the device...
you got to have a look at it monthly...


I was thinking of sealing the hole and buying one of the cute air filters for the device