The largest and best supported Jaguar cars enthusiast site on the Internet!

Serving Enthusiasts since 1993
The Jag-lovers Web

Currently with 3,166 members

Cooling System Routine Service

Cooling System Routine Service

Doug Dwyer

The cooling system of your Series III XJ6 does not pose any particular problem in terms of routine servicing. However, it is essential that you maintain it properly as the XK type engine does not like to be overheated ! Contrary to myth, these cars are not inordinately prone to overheating but are certainly susceptable to ordinary cooling system failures.

The cooling system should be flushed every two years, some owners prefer a more frequent interval. A 50/50 anti-freeze-water mixture is fine although, if you can calculate it this closely, the manual actually calls for a 55/45 mix. The system holds 19 quarts.

The thermostat does not necessarily require routine replacement although some owners do so every few years. If you do replace the thermostat make sure to use a Jaguar replacement or an exact equivalent. Do not use a generic or universal replacement as it won't have the proper bleed holes.

The cooling system has a whole slew of hoses, some of them hidden under the intake manifold. these should be replaced every 5 years or at the first sign of softness, splitting, bulging, or cracking. Remember, hoses deteriorate from the inside out so if a weak spot is visable externally you can bet the hose is on it's last legs. It is also a reasonable assumption that if one fails, the others can't be far behind.

Sometime around 1982 Jaguar went from a metal cooling fan to a plastic one. If you have a plastic fan is very important that you check it often for cracking. These fans have been known to disintegrate catastrophic results. This would be most likely to occur if the fan clutch has seized, allowing excessive fan rpm. Do not gamble here ! If your fan is cracking, replace it and the clutch as well. These parts are expensive, check the archives for alternative replacements if you wish. You can't go wrong with genuine parts but if your budget won't allow it, better to use an alternative than leave a questionable fan on the car. Many XJ6 owners prefer electric fans and there's plenty of discussion on this topic in the archives.

Regularly check the condition of the pressure cap(s). If there is any deterioration of the rubber seal, replace the cap. Caution: Never remove the cap on a hot engine ! There is a very real danger of being scalded !

Hose clamps like to loosen up over the years so make it an annual routine to go 'round and snug them up.

Check the coolant level at least once a month (on a cold engine) and, if needed, top it off to the base of the filler neck of the fender mounted header tank. Interestingly, a number of owners report that when filled to this level a quart or so always disappears, presumably into the hidden expansion tank (inside the fenderwell). Leaving the level a quart or so low eliminates the problem and has no ill effect.

That's about it. No magic involved ! Also refer to "Overheating Checklist" for more information.


Please help support the move to the new site, and DONATE what you can.
A big Thank You to those who have donated already!



Go to our Homepage
Improve your Jag-lovers experience with the Mozilla FireFox Browser!

  View the latest posts from our Forums via an RSS Feed!

Jag-loversTM Ltd / JagWEBTM 1993 - 2024
All rights reserved. Jag-lovers is supported by JagWEBTM
For Terms of Use and General Rules see our Disclaimer
Use of the Jag-lovers logo or trademark name on sites other than Jag-lovers itself in a manner implying endorsement of commercial activities whatsoever is prohibited. Sections of this Web Site may publish members and visitors comments, opinion and photographs/images - Jag-lovers Ltd does not assume or have any responsibility or any liability for members comments or opinions, nor does it claim ownership or copyright of any material that belongs to the original poster including images. The word 'Jaguar' and the leaping cat device, whether used separately or in combination, are registered trademarks and are the property of Jaguar Cars, England. Some images may also be Jaguar Cars. Mirroring or downloading of this site or the publication of material or any extracts therefrom in original or altered form from these pages onto other sites (including reproduction by any other Jaguar enthusiast sites) without express permission violates Jag-lovers Ltd copyright and is prohibited
Go to our Homepage
Your Browser is: CCBot/2.0 (, IP Address logged as on 18th Jun 2024 19:10:40