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Hello,
I have detailed my XJS 6.0 1995 engine and I am very taken with some stainless steel radiator caps, opposed to the Jaguar plated ones that age quickly. These S/S ones are advertised on the internet at the moment, but they only go up to a 15Lb. cap.

However, my expansion cap for the 6L,(think it doe's not matter so much for the filler neck, as it is just a 'bung'??)is rated at 16Lb.
My question is;
Can I get away with fitting this 15Lb. cap on the expansion res?
What would be and has anyone had any negative result fitting a lesser Lb. cap with these late engines?

Obviously, if Jaguar did not think there would be a problem with the 15Lb cap, they would not of changed it to a 16Lb.one. I do believe this later engine might run hotter??
I would be grateful for your views.
All the best
Nick

Hi,
It has been nearly 3 years since I posted my quiry about using some nice stainless steel coolant caps for my 6.0 Coupe(1995MY).
These caps are rated at 15lbs,whereas,I should have 16lbs caps.
Has anyone gone for these since and was there or would there be any notable effect on engine temperature ?
I think the 5.3 V12,s were 15lbs?
Any thoughts?
Regards

Hi Nick, I'm sure the V12 crew will add some technical knowledge in due time but meanwhile I guess the real question is what pressure does your engine coolant system currently run at.

I don't know that, but, I would guess that if it doesn't give you problems generally, ie it has the correct coolant, is filled correctly, has a clear radiator and doesn't overheat in traffic, it isn't reaching anywhere near 16 psi so 15 psi caps should be fine.

I have no idea why jaguar changed from 15 to 16, maybe they were used on other models so it was convenient to simplify supply, stranger things have happened.

(Just in case you do fit shiney 15 psi caps and your car erups like Mount Vesuvius the usual disclaimers apply )

Thanks for the quick reply.
I guess unless I hear otherwise,I might pathfind and see what happens and have my originals close to hand and swap them back if needed(when engine cools obviously!).
These original caps tarnish too quickly on my detailed engine.
Cheers

Crikey! I could eat my sandwich off that! Some superb detailing there! Wish my engine bay was as clean!

Hi Nick, I have 15psi caps on my 93 6.0l , haven't noticed any problems with it.

Regarding your engine, very impressive condition

Thanks for your comments, Paul.
I actually bought those 15Lb SS caps, at a reduced price, which was just as well, because they leak!
Although they look nice, the bendy-toggle retaining clips are too weak (thin SS). They would not give a tight enough seal.
In the end, I purchased some OE Jag 16Lb caps and I just clear lacquered them to keep them looking new, for a little while at least.
Lesson/experiment learnt...
Kind regards