Hi, been in the forums for years...on my 4th Cat looking to maybe add another but don't know anything about the 12 cyl models.
It's got 81k miles 1 owner, etc... Here are the known issues


As usual a few electrical problems...Intermittent window and top operation... Thoughts on this?


Also mentioned it gets very hot near the firewall...?


Any and all comments, suggestions would be appreciated!
Also... Ballpark price range?


Thank You
Bear

 

The V-12 is just somehow different than anything else out there. The good news is that it has familiar things like: spark plugs, air intake, distributor, cooling system just like any other motor. The bad news is that if something breaks it can cost a fortune to fix, assuming you find someone who knows what they are doing. That's why most people who have them develop some degree of mechanical aptitude themselves. Running down the electrical is just time consuming but usually doable. Lift motors may only require cleaning and new lubrication to function correctly.


Clean all debris from between radiator and condenser to ensure full airflow across radiator. Easiest to do if you remove the hood.


Full cooling flush and fill is likely in order as well.


Prices are all over the map. Any body, paint, engine or interior leather work needed is great to drive down price. Pristine examples are out there. There is a blue '86 coupe for sale on the Forums classified as an example.

 

A well sorted XJS V12 is a wonderful car, and by far the best long distance tourer I have had, way better than my AMG Merc (now departed).

Getting a poorly maintained one properly sorted can be time consuming or expensive if you have to pay someone else to do it.

I would be looking for a car with in this order
Excellent interior as these are expensive to replace
Excellent body work again expensive to fix
Mechanicals on the bottom of the list - the 5.3L is cheaper than the 6.0L to fix major mechanical issues just due to the numbers available.

Engines are reasonably bullet proof and I have not heard of 6.0L's dropping valve seats. My 89 5.3L has been overheated numerous times once to the point of spitting ALL of its fluid and is still going, I wouldn't recommend this and it was in the early days of my ownership, once sorted it's never overheated again.

 

Thank​​​, this one appears to be well maintained, I know the seller, it was his father's car and he passed away last year. These are the "Gremlins" he knows about! Any ideas on how much it's worth?
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Thanks​​​, I agree with your thinking, I am pretty decent with a wrench... The 12 cylinder aspect is new to me!
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I'd basically second what's already been said, especially regarding the condition of the interior, and top. My 91 has a pretty worn interior, top also getting a bit rough, and to replace the leather and top will cost close to what I paid for the complete running car.

Also almost everyone on herehere seems to agree on going through the cooling system - the car is almost 30 years old so if nothing had been done it's time.

As far as price goes it seems to vary a lot depending on where you are - in the US they can be very reasonably priced, but it sounds like they are often much more expensive in Europe and Australia.

The v12 difference is mostly just that it's crowded under the hood. Also it's a car of it's time, meaning a complicated mix of analog and basic computer electronics, and at least on my US model, lots of emission control stuff.

Hope this helps, Eric

 

Most likely the relays. Replace with heavy duty 40 amp relays and it will be fine.

 

I live in Australia so no idea on value in USA, someone else will chime in on price.

If you are good with a wrench and the price is right then go for it. Everything can be sorted with time and money.

Windows is most likely dirty switches, the window switches can be disassembled, cleaned and they will work again. The circuit cam be modified with relays so the switch is not carrying full current.

 

I would definitely recommend a cooling flush. Re-coring the radiator cost me a few hundred US $ but made a huge difference in ending the over-heating issues that I had. Also, I'd replace the coils and distributor cap - I had a near fire recently when one of the coils failed, leaving unburned fuel being pumped onto a hot catalytic converter.

Every time I drive it something fails - radio, turn signals, mirrors... I guess it's called character.

My xjs is 1990 V12 convertible.

 

Thanks for the feedback, it's pretty much the same thoughts I had 😎👍! Any more thoughts on this are appreciated
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I just paid $2500 for a '90 XJS V12 convertible with a known head gasket issue and think I did OK anyhow - the body and interior are in such nice condition. Just another data point.

 

That's a steal especially if you can tackle the head gasket yourself. time and patience will enable you to pull the top of the motor off to replace the gasket. This job could easily run into the thousands at a shop.