Failed head gasket AJ6 94 XJS

My failed head gasket , 94 xjs AJ6
I am wondering if very enlarged water passages on the gasket was the reason behind the presence of moderate antifreeze in the valve cover , could the antifreeze sneak pass the weak enlarged water passages to top of the pistons
the picture shows my old gasket next to new and improved head gasket
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Not to be a smart ass (ok, maybe a little :wink:) but, yes it can. it’s called a blown head gasket.

The best gasket is the one that closely matches the mating surfaces the best. if the holes are large on both the head and the block, then that’s the one to have. smaller diameter holes (than the mating surfaces) will result in a gasket failure over time. by looking at the gaskets,

Upon closer inspection the NBC… gasket looks to be a better quality - finished gasket. The EBC… gasket appears to be of worse finish - the water jackets look frayed. Not a clean cut, which begs the question, is that gasket damaged?.
Just ignore all the crap I wrote above. well, Ok, maybe not. - the theory is solid.

To answer your question:
The definitive answer to you question can be answered by the VIN (engine number) the 6 digit (all number) number aka the engine number:expressionless:

AJ6 4.0 liter
Jaguar part numbers for upper gasket sets

engine number up to 107672 Jaguar part number -> JLM12305 (I’m thinking this has been superseded)
engine number from 107673 Jaguar part number -> JLM11649

Supercharged
engine number up to 107674 Jaguar part number -> JLM12305 (I’m thinking this has been superseded)
engine number from 107675 Jaguar part number -> JLM11649

I’ve looked up both part numbers, and both part numbers include the NBC… gasket configuration.

The difference between the two part numbers are the number of gaskets. the 11649 appears to be a top end rebuild gasket set. it appears to include all of the top end gaskets, where as the 12305 is head gasket, cam cover, intake and exhaust gasket only.

hope this helps
Mark

thanks , the top one is my blown gasket

Oh, well that explains it. If it was in the post I missed it :slight_smile: