As similar to my X308 4.0, when I replaced the water pump there were no O Rings with the metal gasket, none on my old water pump.

Same on my X350, what appears as the OE water pump has no O rings and only the metal gasket. Here is the EPC showing the O rings.

I've been searching the Repair Manual and cannot seem to locate specific references to how those O rings might be used, only "install the water pump", no section reference.

In 4 XJ's now I have never seen them on pumps I removed, which does not mean they are not supposed to be installed.

Seems to me I recall some guru discussion a while back the O rings were not needed, that a redesign of the metal gasket compensated for the O rings.

Thoughts?

 

Those 'o' rings are shown behind the pulley and I can't see why you would need them there.

just use the gasket as shown and have a look when you change the pulley over-I bet there are none there!

 

The original pump is not a single piece like the replacements, they come apart.
Are those there for that purpose, or for another car that uses the same pump?

 

I'll pull apart the old pump and see if the O Rings exist inside the two pump pieces by the measurements.

 

The 1 piece AC Delco (replacement for the 2 piece) I purchased has one large O ring that fits around the back of the pump assembly where the impeller inserts into the block. It is large enough that the gasket just fits over it. I thought one of the O rings shown in the diagram may be actually be of it. It is over 60mm in diameter. The smaller O ring could fit on the insert over the impeller and could be different for other applications.

 

Depending on which pump you buy, some are designed to seal with the o-ring, some with only the paper gasket. I installed an Airtex pump many years ago on my 308 as recommended on this very forum that used only a paper/composite gasket. The original pump had an o-ring and I remember being puzzled why the replacement didn't come with one and had no groove to install one, but I put it on anyway. Then like a year later, on a road trip, going up the side of a mountain, that paper gasket began leaking pretty badly and I cursed the choice. After nursing it home with jugs of water, I researched and found the AC Delco pump was designed to use the o-ring and replaced the Airtex crap with the AC Delco, an o-ring and I believe it was a metal gasket IIRC. That's been like six or seven years ago now and its been fine ever since. I don't know what that second o-ring is supposed to be in the diagram. I only remember one.