Can someone point me to a link or document that has the proper procedure for filling the cooling system on a 1987 XJ-S V12? My used Haynes manual is missing a large section on the cooling system.

Thanks,

John
1987 XJ-S, V12

 

JCR

There are just about as many different opinions on this as there are on which oil to use! This has always worked for me:

• Turn LHS aircon knob on to FULL heat and turn the RHS ircon knob to deforst (pointing upwards)
• Park the car on a slight incline, or put the front on a ranp or similar.
• Take the off the middle filler cap (on the cross pipe) and off the tank on the wing just behind the LHS headlight nacelle
• fill the car by the middle filler until the fluid flows out of the wing cap
• replace cap on the wing tank and start the car
• warm up gently topping up any drop seen in the centre filler spout and when warm remove the bleed stopper on the LHS top of the rad (opposite equivalent place to the bleed pipe banjo that is on the RHS of the rad)
• replace centre cap and rev the engine a bit and top up the bleed hole as any drop in level shows itself.
• replace bleed screw

After a day or two of driving, top up the two fillers and when cold undo the bleed screw and top up there if needed.

I have dispensed with the catch tank behind the LHS wheelarch. I just carry a small wooden dipstick in the boot, and when cold, I test the level in the wing tank with it. As long as there is 3 inches or so in there, all is well.



New pressure caps are a must, best make you can find (eg Stant has worked for me). If you can find one, fit a solid, non-sprung cap to the centre filler tube. For some reason or other there are often losses through this cap. As soon as I fitted a solid cap there, all water losses stopped on my car.


Greg

 

Hi guys,

Is there a special procedure for the 4.0 engine? Are air-locks common?

Paul

 

Thanks Greg! I appreciate it.

Regards,

John

 

The side pressure cap is the pressure relief. The center one should be sealed. If you use a standard pressure relief cap in the center it WILL leak unless you use a cap with a greater rating than the side cap. There is no problem using a 20lb as the side cap does the relief. Much easier to find than a solid non pressure relief cap.

 

FWIW, I use no special procedure on my XJR with the 4.0. This engine doesn't seem prone to air locks....at least as installed on the sedans.

Perhaps XJS-specific cooling plumbing might pose a problem, but I haven't heard any reports of difficulties.

Cheers
DD

 

Hey guys thanks much for the info! After 2 months on stands, I started it up and drove it last night! I just picked up a 20lb that I'll put on the crosspipe. The wing tank has a 16lb on it, so I should be good.

Regards,

John