V12 6.0 cooling
 

Hi
I may be missing something really obvious but can anyone post a photo of the bleed screw for the 6.0?
All I can see above the radiator is what looks like a circular (tubular) plug,
Also am I right in assuming there is no radiator cap on this model? If there is, where the hell is it and if there isn't, where do you fill the system? I can only see the expansion valve cap.
Photos would be helpful.

My car is 1997 DD6 6.0.

Thanks

Might get more information in the XJS ( X27 ) section as it is the same engine in the X300 body / engine compartment shared components , try to stay in the 1997 range .

There is a search box in the upper right corner on this website .Example :

https://www.jaguarforums.com/forum/x...r-leak-197007/

http://www.jagrepair.com/images/Trai...20-%202000.pdf........see page 193

Is this the bunny ? This pic is from a reported 1994 and the X300 has the similar black cooling expansion tank except more square in the lower section of the pic

https://www.jaguarclassicparts.com/u...rvoir-assembly

https://cimg2.ibsrv.net/gimg/www.jag...d204c7fd3b.jpg

G'day 9mm,

According to the service manual the cooling system self bleeds if you run the car with the heater on. The highest point in the system is the filling point.

Cheers,
Jeff.

No bleed screw.
No radiator cap.
Fill at expansion tank.
Who are we to question Jaguars wisdom?

Apparently, they made the XJ81 (V12, XJ40 body style) as a Daimler Double Six for markets outside of the USA. That's cool. Must be rare.

Hello, I have a jaguar xjs v12 6.0, I would like to check the command point does anyone know how to do?

The expansion tank is your fill point.

G’day Gents,

Apparently heat soak after engine shutdown and therefore no coolant flow is when heat damage can occur I.e. dropped valve seats. Now with my car, more often than not, the radiator cooling fans run for several minutes after shut down until the coolant temperature has decreased and apart from some convective effect there would be very little, if any, coolant flow through the radiator.

I was wondering then whether activating the electric coolant pump at the same time as the cooling fans would be practical or beneficial.

Any thoughts fellas?

Cheers,
Jeff.

Did you mean the heater circuit pump Jeff? What other electric coolant pump would you mean?

I remember discussions about this on the XJS forums. Many are of the mindset that coolant flow after shutdown is prudent and useful. It could reduce the likelihood of dropped valve seats. Others say not, and it was never designed that way even for the old V12 XJ-S.

The Jag V12 has a coolant take-off above every cylinder. Notice how the 6.0 has 5 of them blanked off. Older V12s had 4 blanked off. None were designed with a coolant circulator pump to run after shut down. Apparently the engineering staff was happy enough about the cooling capabilities of the engine as they designed it, hopefully taking into account heat soak after shutdown. Of course this applies to a new and/or well maintained car which is not often the case as the car ages, and changes hands. All bets are off then!

I would actually feel better if there were a coolant circulator pump, since I live in very high ambient temperatures. I am concerned at times, it is just so hot and I can't open the hood after each drive! It is more of a feeling than based on science.

That being said, I haven't had a problem. Tap on polished burl walnut. :icon_wink:

Gday Richard,

Yes that was the pump I had in mind but on examining the schematic and the car then running that pump would only circulate coolant through the heater matrix and not the engine so of no practical purpose.

Cheers
Jeff.

That's what I had concluded too. With some careful planning I suppose a heater circuit pump could be connected in line somewhere, with the thermostat switch in control. It would make some sense to put one at the lower radiator hose, to keep feeding the engine after shutoff. But it all seems rather arbitrary.

On a related note, I would like to find a way to keep the heater circuit valve closed after engine shutoff. At shutoff the valve opens and allows heat soak of the coolant in the heater core. Then follows the blast of hot air upon a hot engine restart, which is annoying and wastes a/c efficiency.

For a few years now, my solution to heat-soak is putting a fan in front of the car when I pull into the garage. I leave it plugged in at the front wall and when I get out, I put it in front of the car, angled slightly downward. The air movement through the grille (radiator) and draft under the car pulls away the heat. Yes it heats up the garage but I usually have the door open during the day anyway, except in winter (when a warm garage is nice to have!)