Classic/Antique Car Repair: switch fuel tanks, jaguar xj6, fuel tanks

Question
Thanks.  But I still don't know if the car should be *driving* or *stopped/parked* when I switch the tanks.  I didn't want to cause any damage.  (Please forgive my stupidity.)

Terry

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Followup To

Question -
I just bought an '87 Jaguar XJ6 yesterday.  It's great and in immaculate condition with only 127K miles; can you believe that?!  My question is how do I switch between the fuel tanks?  I understand how the button works and how to tell which tank I'm running on, but do I switch while going down the road, while stopped or what?  I can't find this anywhere in my owner's manual.

Thanks.

Answer -
Hi Terry,

Push the switching button so it is in the "out" position and look on the side of the button.

The switching system has a fail safe system built in so that if any component fails electricly, it will default to the left tank.

Howard

Answer
Terry,
The switch can be operated anytime driving or parked. It is good to switch back and forth between tanks so as to keep all the switching valves operating and to keep the fuel from getting stale in one tank. People who always run off of one tank and use the other tank as a reserve are in danger of having the switching valves stick and not operate when needed. You are not stupid to not understand this system as it is strange and even some Jag mechanics have a hard time with it. But it is an efective system. It not only switches fuel supply, it also switches tank sending units to the gauge and it switches the fuel return system as a large portion of the fuel pumped forward is returned to the tank that it was pumped from. Both tanks maintain a 2 to 3 lb. pressure in the tanks and the fuel is cooled by your AC system. I have an 83 and an 87 I use as my family car. I like the looks of the car and the driving and handling. They are however high maintaince cars and are prone to driping oil. In responce to critics of the ser. 3 Jag I tell them, "My cat is not leaking oil! It is just marking it't territory" and the high maintance responce is, "This is like an F-18 fighter, it requires several hours of maintanance for each hour of flying time"
Howard