A common trope about the Jaguar V12 engine is that it leaks….frequently…and a lot. Well, my experience supports that generally held view.
The car didn’t leak noticeably in the first couple of years that I owned it, but starting in about 2002 I noticed that it would leak on first start up and then not at all when completely warmed up. It is now to a point where the leaking is ridiculous. Here is a video I shot tonight right after starting the car to give you an idea how bad it is.
I used synthetic motor oil in the car for the first couple of years, but when the leaking started, I changed back to conventional oil after convincing myself that combining synthetic oil with old, low tech gaskets was not a good idea. I think frequent oil changes with conventional oil is fine for this engine.
When Ford owned Jaguar, they improved many of the gaskets on the V12 and these can, and should be used on the older engines. Many are a black gortex material around a thin foil that seal much better than the original paper gaskets.
I have addressed many of the common top end leaking areas such as the valve cover gaskets and half moon seal and banjo bolt washers.
The rubber plug in the timing cover gets brittle and does not seal, also causing leaks.
It is now time to tackle the bottom engine gaskets so that will be this winter’s main project. Luckily, others have gone before me, so there is good information available. The best is Bernard Embdem’s writeup on the subject. I will follow Bernie’s guidance as I start this project.
To get access to the gaskets, I will need to drop down the front suspension….but the engine will need to be supported before that, as the front suspension cross member typically does that job.
Jaguar made the following device for supporting the engine during projects such as removing the front suspension.
Sean Straw makes and sells an after market version.
Bernie made one of his own and I followed his directions to the letter. I only need to make two modifications for my car. The XJ fender bodywork must be higher than the XJ-S as I had to fashion the two feet for the support from the 2×6 instead of the 2×2. This raised the support enough that the readily available 1/2″ by 10″ eye bolts from home depot were not long enough. I ordered a couple of 1/2″ by 12″ eye bolts online and these worked great.
Next up will be dropping the suspension.