1968-'92 Jaguar XJ6 | What you need to know

Photograph Courtesy Jaguar

[Editor's Note: This article originally appeared in the September 2018 issue of Classic Motorsports.]


Dave Welsh
Welsh Enterprises
(800) 875-5247

Convert the original self-leveling rear suspension, if the car still has it, to conventional shocks. The self-leveling system is known to fail, and trust me it will. And when it does, the cost to repair or replace it can be astronomical. We sell a conversion kit that includes all the parts you need. The part number is JLM11698K.

If you’re shopping for an XJ6, there are a few things you should keep an eye out for. First is the brake accumulators and switches. When were these parts last changed? Were the cam and head gaskets ever replaced? Was the rear differential ever replaced or rebuilt? Does the car have the original self-leveling rear suspension kit or was it converted over to conventional shocks?

Low mileage is always a major plus in a used car, but it’s especially important in an XJ6. Once you have your new-to-you XJ6 in the shop, start by checking the cam covers and rear differential for any kind of leakage. These cars are known to leak badly in these areas, especially if there’s more than 80,000 miles on the odometer. I recommend changing the differential fluid at this point as well as every time you change your oil and oil filter.


Paul Tsikuris
Tsikuris Classics
(863) 858-7981

All three generations of the XJ6 have their pluses and minuses. The first generation, with those low-slung bumpers, is widely regarded as the prettiest of the three, and the Series 3 cars have a much more reliable drivetrain. The automatic transmissions in the Series 1 cars are archaic and don’t shift well. Converting to a four-speed gearbox with overdrive–as the car came in Europe–is a big step in the right direction.

Series 2 cars (specifically the XJ6C) have gone up in value and are very good-looking. However, most of the interior, especially the switches, feels cheap. This is much improved in the Series 3 cars. The engines in the Series 3 cars were much less prone to overheating thanks to larger water jackets in the head and block. You can identify one of these engines by two parallel castings in the block that run top to bottom.

Keep an eye out for rust around both the front and rear windows. These cars tend to rust there. Once in an accident, the bodies on these cars are difficult to get straight. You can gain some insights on the car’s past by studying the body panel gaps.

Try to remember to park the car with the steering wheel straight. Parking with the wheels turned stresses the steering rack seals over time and makes them degrade faster. In stock form, the rear brakes are very difficult to bleed. We recommend running a steel brake line from the factory bleeder under the car to a location that allows for easier access. If I could make my own XJ6, I would use a Series 2 body, Series 1 bumpers and the driveline from a Series 3 car.

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hurstad New Reader
3/1/19 11:51 a.m.

Problem is, by having this cover 1968 - 1992, you're really talking about two completely different cars. Up to 1987 was the original XJ-6 in its various permutations. 1988 - 92 was another. IMHO, the 85-87 Series III VDP is one of the most beautiful - and reliable - motorcars ever built! We've had several.


RMVR53 New Reader
3/1/19 10:46 p.m.

Dave's comments cover the XJ40 (the 88-92 variant). The S3 body shell continued past 87 to 92 but only in V12 form. So the XJ6 is from 68 (69 in the US) to half-year 87.  I have owned several S2's over the years and currently have 3 S3's (82, 85 and 86). To me, the best is the last (85-86) as the 87's were kinda ignored. They were more for using up parts before the transision to the XJ40.  I would love to find an S1 and put a S3 engine in it but stick with carbs. You can't use too late an engine tho as the mount bosses changed in 85 so an 84 or earlier block would be required. I've got an 83 long block currently being prepped for an S2 E Type. 

I only have 284,000 miles on my 85 so all those people that say the cars aren't reliable are full of crap...

johnorm New Reader
4/3/23 9:38 p.m.

I had a XJ40, 1988 model, and it was a problem plagued POS. My 1994 XJ6, on the other hand, was brillant with only minor issues. Both cars were exceptionally smooth at highway speed and as you went faster they seems to hunker down in a most convincing way. The XJ interior was and still is one of the most beautiful examples of a truly luxurious interior. How can you possibily go wrong with a burled wood dash, Connolly leather and if I'm not mistaked wool carpets. The seats were so comfortable that my wife would fall asleep when we went for Sunday cruise. I prefer the 85/86 year models from a styling point of view but my '94 was so problem free I would go back to that model.


ancientdan New Reader
6/25/23 5:54 a.m.

We love our burgendy 89 XJ6 .  It has only 60k miles, doesn't leak anything and drives like a cruiser. My wife just one first in class at our Original British Car Day with it and was thrilled.   We are ancient and she doesn't drive any more, but she encouraged our latest buy, a 94 XJS convertible with a 5 speed.  She says we now have a set!  Our last Jaguar was a 1953 Mk.VII Sedan which was our only car for a few years early in our marriage (57 years and counting).  It was well worn and unreliable, but we loved it anyway.  

Low mileage and good service records are the keys to happiness in owning an older Jag. 



frenchyd MegaDork
7/2/23 2:50 p.m.

I picked up 2 rust free XJ 6's One is a SWB  1972   52,000 miles  the other is a LWB 1986. 91, 000 miles Both running,  nice interiors.  Leather was hard on both of them but leather treatment soften  t right up.  Not quite as glove soft  as new but a few more treatments should get it there.  
  Both will need paint. The 1972 because of over aggressive buffing of the Lacquer finish.  And the Green 1986 because it used  GM's "plastic" paint which Is cracking.  If it hadn't been stored indoors for the past  27 years it likely would be gone

  The 1972 is getting a V12 and a tow hitch.  The Green one I'm giving to my grand daughter for college.  

 I picked them up after Halloween last year for $500 each.  In Minnesota that's when the deals pop up. Once storage is lost and snow is coming. 
  The 4.2's engine  life is almost totally due to how it's cared for.  Proper oil changes  based on time rather than mileage it is capable of 3-4 decades of trouble free life.   The Borg Warner transmission is similar. Change transmission fluid every 5 years or 60,000 miles.  But the Borg Warner is a very old design with  more than 2x the slip of the later GM Turbo 400. ( used in the V12's) 
       Most electrical problems are typically caused by poor ground.    Before replacing  the component check the black wire coming from it to ground. ( hint:  just because it's connected doesn't mean it's good.  Corrosion is very common ).  
       The earlier short wheelbase models are more nimble than the long wheelbase models.   
They respond well to shocks at some  cost to the soft floaty feeling.  
     British  rubber of that era is horrible but some  ( repeat some) aftermarket rubber bushings are superior.   Replace all coolant hose with silicon.  Otherwise replace it every 5 years regardless of use.   
  Fuel line is a scary situation.   When EFI  first  was introduced rubber just wasn't up to the heat and pressure.    So anything pre 1986 should be replace in 5 year intervals ( at a minimum )  unknown maintenance  means that should be first on your todo list.  If replaced with  modern good quality fuel line  that life will grow accordingly. Unlike American systems pressure is only 30-35 psi. 
By the mid 1980's BMW helped out Jaguar and advised them which fuel lines were good and even connected them with a good  seam sealer   Which really helped with the rust issue. 

frenchyd MegaDork
7/3/23 3:53 p.m.

As far as the newer XJ6's  the 4.0 liter in line aluminum 6 with 4 valves per cylinder has been remarkably   durable and easy to work on.  
    It puts out nearly the same power as a 5.3 liter V12  and actually significantly more in the supercharged version.   Combined with improved build Quality and lower total weight.  It's performance is significantly superior. 
  And it doesn't have the difficult to work on inboard rear brakes of the earlier cars. 
     It also benefited from Fords parts bins.   Some components can be cross referenced with English Ford.   

frenchyd MegaDork
7/7/23 9:19 a.m.

I've got a tiny car budget  which is why I use Jaguars. They are remarkably durable mechanically.  Let down in the 70's and early 80's by labor unrest 

By the mid 80's the labor issues were  well over and employees were eagerly working to improve quality. Reduce building costs so Jaguar could once again return to profitability. 
  That's why quality improved so much after the mid 1980's 

      Parts are readily available at prices cheaper than Ford or Chevy parts because there is so little demand for them. 
If you are a DIY  guy with even moderate skill  they are really straight forward to work on.  They were put together by assembly line workers who were paid flat rate to do the job. Not hourly. And the pay was miserably cheap. Hence all the labor problems. 
   When Sir William Lyons. ( yes I know , Sir William)  ran the company there wasn't  labor problems.  But once the guys from BMHC  took over problems mounted   When John Egan ran the company labor problems went away. Quality massively improved. 

frenchyd MegaDork
7/7/23 7:20 p.m.

 There are some "tips" that will save you massively. For instance doing the rear brakes it takes less than an hour to drop the whole rear end cage.  2  9/16 bolts on each side .  Drop the 2 trailing links,  Then disconnect  driveshaft, exhaust and brakes.
        Do it with a floor Jack. And roll the assembly out.  Brakes are real easy then.   It takes even less time to put it back because you won't be fighting rusty tailpipes.  Oh and before you put it back?  Buy the Moss motors remote  bleeders. Life just got massively easier!!   Of course you can skip all that.  And try to fit hands in places hands don't fit. Tearing up your hands and dropping grit dirt and grease in your eyes .  while  trying  for 12 or more hours to do it.   
   Use 20w50 oil and because valves are softly sprung the lack of ZDDP  in the oil isn't the death sentence it is for camshafts  that pushrod motors have.  I add it because  it helps in other areas and it's a way to get 300,000 miles before the engine needs work.    
      Change the oil every 6 months even if don't get 3000 miles on it.  The acids you dump out when you drain it won't be eating away at stuff.  
    5500 rpm is the factory redline.  It will take more but that long stroke (4.17)  ring wear  goes up dramatically. Some of those engines are  over 50 years old.   Nearing grandpa status. Treat them like that. If you want them around to 100 

 Oh and leave the metric tools in the box.  The English taught us an inch is 3 barley corns from the middle of the ear.   A foot is 12 of those inches And other such wonderful ness.   
  One thing I've always been amazed by is the quality of the bolts used in Jaguars.  30-40-50 years old  bolts usually come right out .     Sigh !  Until Ford bought out Jaguar. A 9/16  wrench or 1/2 inch socket etc.  was all you needed.  
   Then Ford fell in with the French who apparently can't do fractions. 

frenchyd MegaDork
7/8/23 11:59 a.m.

Jaguars have solid lifters.     So  the earlier versions  will sometimes give a little valve clatter until they are properly warmed up. 
    Jaguar stayed with the same basic camshaft they had from early XK140 days.  They changed the entrance ramps slightly several times working to eliminate that clatter.  So each version got a different part number.  
      Short trips where the engine doesn't warm up fully tends to wear the adjusting shims. Then eventually the clatter is always there.    Use something else for those short trips because adjusting   Valves is a multi hour task filled with potential for disaster. 
although I've heard  cars with 100,000 miles and valves never touched be as quiet as a church.   The timing marks are on the bottom of the  crank shaft  vibration damper.  Once on Top dead center pull the valve covers off  and using the cam alignment gauge  make sure you are  right. The notch on the gauge  will fit into  the notch on the camshaft and sit down on. Both  sides of the cam  ( where the valve cover is ) 
   Jaguar made a couple of brackets to keep the cam gear from slipping and losing the timing chains.   Once the valve covers are off  measure each valves clearance.. (write them down ) Then Bolt the cam sprockets to those brackets.   1 turn at a time remove all  the nuts on the cam bearing caps.    If you remove just one bearing cap at  a time you will bend the camshaft. 
   If you know what you are doing and have a good selection of the required  adjusting shims.     A pro can do the whole job in an hour.   Don't try for anywhere near that time until you've done at least 20. 
      Once the camshafts are removed pull out the cam follower  and look carefully at the top. If it seems to have concentric rings in it, or with a straight edge laid across it there is any sir gap. You will need new ones and maybe new camshafts. 
    Assuming all is still good pull the shim out .  If there is a dent in the center  measure  the shim  with a micrometer  near the Undamaged edge.  And write that down next to the valve clearance. 
 More later 

wspohn SuperDork
7/8/23 1:50 p.m.
frenchyd said:

      Short trips where the engine doesn't warm up fully tends to wear the adjusting shims. Then eventually the clatter is always there.   

I'm not getting that.

The shims sit sandwiched between the cam follower, which can only move in a straight up and down direction, so there is no side play which would tend to wear the shim the way a pushrod rockers slides across the valve stem, causing wear to both rocker face and valve stem tip..

We have the same set up in the MGA Twin Cam world and we almost never see any signs of shim wear given the inability of this system to allow any radial rubbing.  The only reason they need reshimming is because the valve seats wear with extensive use and a new valve grind and  different shims ar necessary.

frenchyd MegaDork
7/8/23 2:33 p.m.

I've pulled too many Jaguar engines apart  where there are wear spots  right over the valve stem.    The shim has a slight amount of movement  possible  and if started up cold with all the oil drained   It can happen.  
  I'll find shims like that for you. 
 This one is only slightly dimpled. .003  but you should be able to see the slight ledge.  
  I use ones like this upside down on the race motor.  Never on anything for the street. 

frenchyd MegaDork
7/8/23 2:56 p.m.

In reply to wspohn :

I agree that is normally when Re shimming is called for.   But get someone who revs the engine stone cold before any oil is around and it happens.   I can't see anyone who can keep a twin cam MG engine alive doing anything that horrible. 

frenchyd MegaDork
7/8/23 4:34 p.m.

Any cam bucket that has the proper clearance leave it in place.  Those that aren't correct  pull off the cam bucket. And measure the shim with a micrometer.  Factory shims have  a code on them  but typically that is gone by now.  Calculate how much is needed to bring the clearance back to factory. Careful  to put the camshafts  back as they originally came out.  The notch on the top will fit into  the cam tool when correct.  And only tighten the nuts one turn at a time. You don't want to bend the camshafts going back together either. 
  When everything is done and the bolts holding the camshaft  are  properly torqued 
  And safety wired  turn the engine over by hand a few times to settle everything and recheck clearances. 

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