Dear XJS Enthusiasts,
About two weeks ago I posted pictures of an XJS 1992 5.3 that I was looking to purchase. The engine was a bit "rough" around the edges but the body was immaculate. I have decided to pass on this car. Thank you all for your comments.

From my signature, readers can see the I own a 1993 Daimler Double Six 5.9L.

My questions are:
Is the 1994 XJS 5.9L engine the same as the XJ40/Daimler Double Six 5.9L?

Does the XJS 5.9L engine have the same issues with "overheating," and the potential for fuel hose fire from poorly maintained hoses as the 5.3L V12 pre and post-facelift?

Are there any significant differences between the 5.3 and 5.9L engines?

Thank you in advance!
Charles

 

Charles,

In order of asking:

Yes
Not as bad, the cooling system upgrades helped, but neglect is the same result. The Injectors are "plug in" so 12 less hoses to leak, but there are still fuel hoses that need attention.
Many, the core engine is the same, the bolt ons changed significantly. A very long list.

 

Haven't heard of the 5.9. Is it different from the 6.0?

 

Sorry, I didn't round up to 6. (5.993L).

I know this version has the same transmission as the DD6, the 4L80E and outboard brakes replaced the inboard brakes on these models.
In terms of "looks," I find the two back seats and aerodynamic front bumper as a "downgrades" to the earlier 5.3L convertible.

 

The 6.0 liter came after Fords purchase and reflects a massive amount of spending by Ford to seriously reflect quality improvements.
The earliest 92to early 1994 reflect the very best made V12’s. For us racers the second batch of 6.0 liters was a slight step backwards. Instead of Forgings of EN 40 steel that were subsequently heat treated to harden the bearing surfaces. The crankshaft was made of sintered Iron. That is perfectly acceptable for highway use. Most modern crankshafts for the street are sintered iron and it’s very durable if not to the extreme degree the Forging is.
The rear seal is also improved from a separate 2 piece to a single one piece much more modern seal.
In addition the transmission went from a 3 speed to a 4 speed overdrive transmission. So even though the engine makes 50 more horsepower than the 5.3 liter it nearly gets the same fuel mileage.

The last run of 6.0 engines made the most reliable, easily repaired engines of an obsolete idea. Newer cars are better in nearly every way except a direct lineage to Sir William Lyons. They make excellent vintage cruisers. Because of that connection they will appreciate quicker than newer cars which are still in depreciation.
Mind you condition is everything. A well maintained good running car can easily be a better value than a freshly restored one.

 

I had a E- type that overheated (circa 1970) in Denver. My solution was to add an oil cooler. That solved the problem. Used hoses that were about 3/4 inch in diameter. Used a racing cooler about 12 inches square. Can't remember much more