I have seepage that (I hope) appears to be coming from the drivers side oil connection to the cooler and which (I hope) is caused by the O ring. I am having a little difficulty with a parts vendor, in identifying whether the 1997 - 2002 oil cooler uses the same O rings as the 2003 - 2005. Can anyone advise me on this? Thanks.

 

Are you talking about the engine oil cooler, the power steering oil cooler or the transmission oil cooler?

 

Normally, the line itself is the problem. I read they have a life expectancy of 10 years, so it is a maintenance item. They are normal hydraulic lines, same as excavators and the like. I would replace it ASAP, as they are known to fail, dump all the oil on the pavement and, at best, leave you stranded. The worst case is an engine running without oil.

There is apparently an old and a newer design for the crimping of the rubber line to the fitting. The newer one is reputedly better, but mine leaked anyway. I replaced mine with a Jaguar part, but folks have had them "refreshed" at local shops that service hydraulic machinery for less money, especially if you want to replace all 4 lines. The driver side, off the engine, is the pressure side, and the most likely to leak and possibly fail. That is the only one I replaced on my car. It is fairly easy to replace in about an hour, no need to drain the oil, and can be done with the front of the car on ramps. From memory, the Jaguar line I got only came with one o-ring, so I had to reach out to my stash for the second one.

Best of luck, keep us posted.

 

Thanks for the responses. To clarify: it is the engine oil cooler that is seeping. It is the DS (the pressure side : thanks!) and there is a coating of the dirty black stuff at that corner of the cooler elements, and around the incoming connection. I was hoping that the issue would be the O ring, but I am not hearing encouraging things :[ I'm not sure how such a comparatively low pressure could be the source of routine failures, due to the line itself, but I would like to know if I have the correct size O rings. Is a 2002 or earlier, O ring the same as a 2003 and later (I have an 05)? I would assume that the O ring would have to be replaced if the line was disconnected anyway. What is the removal procedure for the section to be re-manufactured by a hydraulics company, and what sort of connection has to be broken at that point, and does it, too, need an O ring?

 

There are tons of posts about the oil cooler lines and cooler. Here is a recent one with a parts diagram:

oil-everywhere-148058/

This is altogether hydraulic lines, not something Jaguar made up. Yes, all the connections use o-rings and are secured by a screw. In your case, there might be a problem just at the cooler end, but I would check the engine side as well. The 2 lines (feed and return) hook up to the engine very low under the belts. A mechanics mirror can show if there is a leak. The troublesome leaks are at the crimping between the rubber line and the aluminum fitting.

FWIW, Harbor Freight has a good selection of o-rings for emergencies...