Hey all, I came across a 1988 Jaguar XJS V12 with 155k on the clock. The person is asking $1200 for it but it needs head gaskets according to the add. I did the timing chains and tensioners on my present XJ8 and well, am looking for a new project I guess. I've done quite a bit of searching around and have had difficulty locating diagrams and instructions. This will be the first time I do a head gasket on a car (of course it had to be a V12 ) but I have seen it done and know how to do it for the most part.

Are there any special tools I will need to do it, and as far as head gasket jobs go, is it easy/hard/moderate? I noticed in several pictures of the Jaguar V12 that it has overhead cams and will need its timing chain removed. Are there any special procedures for it like on the XJ8?

Should I even bother with this? Part of me wants to take on the challenge, but the other part is concerned I won't have the time, patience or know how to get it done. If this were the head gaskets on my Range Rover, I would do it in a heart beat, but this V12 looks intimidating.

Any and all input is greatly appreciated, thanks in advance!

 

You should really have the actual shop manuals for this job, IMHO.

There are special tools for releasing the timing chain guides and tensioners....whether or not they are truly essential, I can't say.

You'll need to buy/rent/fabricate a head puller tool as the heads are (usually) virtually impossible to remove without one. I think Motorcars Ltd sells one ($350?) or you can search for diagrams on making one. Someone on this site may have posted the info. if not, it should be out there on the internet somewhere.

Cheers
DD

 

I've done headgaskets on everything from single piston engines to the big diesels and everything in between. The original motor in my XJS had blown headgaskets and after pricing the tools and parts, I found it was cheaper to purchase a good used engine and switch it.
I still have the original engine and I haven't decided if I will rebuilt it or do something else with it.

 

Ok, here is V12 Jaguar, Craigslist to Reality translator I developed by living in Ohio for the last 19 years, for your convenience:

1. "needs head gasket" - was ran hot for a while, has warp heads, probably weak bottom end
2. "needs a tuneup" - right... missing compression in half the cylinders, half of the items are unhooked, because owner and all of his cousins already took their cracks at repairing it.
3. "perfect body, just few small surface rust areas" - body is shot, freshest layer of bondo is coming up already
4. "all it needs is..." - car was given to current owner by his buck toothed neighbor as payment for inbred husky puppy that ran away, or died already, no one in the county truly know when this car ran and what it desperately needed at that time.
5. "Paint is nice, only needs a good buff" - MAACO did an excellent job and exceeded its 12 months glossy look promise, this was 1993, so you might be buffing and stripping the same time.
6. "Car always ran fine, used to drive it to work and back daily" - current owner is not lying on the last part, however they might not have been employed since the Bush senior time, so all the above might apply.

In short, 155K miles is my "run Forrest run" on this one, since I guarantee you that head gaskets will be first and by far not last thing it will need.
Market has no shortage of clean XJS's that need work, so pick one withe least mileage.

 

A question; how many XJ,and XJS are still running,compared to how many are not running?

 

3

 

There were about 120,000 or so XJSs built. In the UK I would be surprised if more than 3000 survive on the road, and maybe the same in the USA, relatively few were sold everywhere else. So I put my money on fewer than 8,000 worldwide actualy road registered, and fewer than 5000 would not be a surprise.

Greg

 

Between 1975 and 1996 there were 114,400 XJS's built. As they were mainly built to appeal to the American market I suspect the majority were shipped here.
Considering how often I see them I would guess there is more than your guess of 8000? Judging by how often I see them, the frequency they appear in ads and the number of members here with one (or more) I think the numbers are probably closer to 30,000.
Of course, this is only my opinion.

 

OK fair enough, now how many of the lot are actually running or driveable?

i know locally of maybe 6-7 XJS ,but only 3 run good enough for a long trip.

what i'm saying, were they a really good car, or we like them because of they are unusual, and 12 cylinder engines? like a novelty vehicle, or an amusement thing.

 

See above, worldwide 8000 tops, 5000 probably says my £10.

I think they are a really good car AND we like them because they are unusual AND we like them because they look absolutely wonderful. Before retirement (and consequent fun-petrol money reduction) I did 100,000 miles in mine as a daily driver over about 7 years, when the car was already 15 years old and it was superb. All over the UK and europe. They go better for regular hard use, I believe, particularly the anciliaries like aircon and the electrics, and the brakes. You get through rotors and calipers and tyres and shocks mind, but by supercar standards they are very robust.

 

My 88' does not run on the right side nor does it suck in air through the intake. Any idea what the problem can be?

 

How are you checking for this?





If you're checking this at idle, there is no problem. It's normal to not feel any suction on the RH bank at idle

Cheers
DD

 

+1, at idle air feeds through left intake into both manifolds.

 

Even when you rev the engine no suction.

 

I Don't understand. How does that work?

Plus the air filter is dirtier on the left bank and the right bank is clean