89 XJS 5.3 V12 How much coolant does these engines hold. I was going to drain, change thermostats, and refill. Not sure how much i should buy keeping in mind loosing plenty doing a bleeding procedure. Is there a paticular coolant to use, that you can get at any autoparts store?

Bleed procedure:

Some have said to open the filler cap(center), header tank cap(left side), and bleeder screw. Run engine and keep adding untill coolant is flowing out of bleeder screw opening, close bleeder screw. Fill full at filler cap, and close. Fill at header tank, then close. Does this sound about right?

 

The system hold about 4 or 5 gallons total. Some always reamins in the engine. When I drain one I use 2 gallons coolant and top off with water. I use ordinary old fashioned Prestone.

You've got the basic of the bleed procedure. It really helps if you elevate the left front corner of the car about 10 inches or so....that way the air pockets want to rise towards to bleeder hole. Run the engine slightly above idle speed. Turn the heater on. It is not required nor desirable to *fill* the metal header tank. Half way will do the trick.

It's a messy job. When things really start flowing and burping you'll have coolant coming from both the filler and the bleeder. I don't know of any clean way to do it.

Cheers
DD