I did some fluid checks this morning from cold, and popped the coolant reservoir cap, and without actually dipping it, looked down and though she could use a tad. -I mixed some 50/50 water & coolant in a 2-litre Pepsi bottle and poured some in, and one litre later, gurgled up into the filler neck.
Now I read in the filling/bleeding/purging for air in Nigel's book(and perhaps in one of the threads), to fill until it flows out the top neck and bleeder tube.
* Question is, did I overfill it to the point of possibly "popping her cork" and blowing a hose, or will it simply purge any excess coolant as it warms up, out the 15psi pressure caps? -Should I drain some back out from the bottom somewhere, hoping to find a drain **** if so?

 

Greg,

Assuming a V12 here, and no idea of year?.

The header tank in the LH side of the engine compartment should be FULL, and the expansion is taken up by the atmospheric tank inside the LH inner guard panel (rearward of the LHF wheel).

I fill mine with the centre/header caps off, the bleed plug out. Filling via the centre spout until coolant flows from the header tank and/or bleed hole, then cap the bleeder and the header and continue filling at the centre until it too is full.

The atmospheric tank needs about 2ltrs of coolant in it, and the hose going TO the header tank must be clear, they do block up regularly, so worth a check in all cases.

I then run it with the heater tap ON (or the small vac hose off), until the temp rises a little, then shut it down and let it draw coolant back from the atmospheric tank as it requires. Then do it again. Bleeding these can be a MONGREL, but mine is not, it is so easy to bleed, so maybe I am just lucky??.

 

Apologies Grant et al, Yes, '89 XJS with almighty V12.
Thanks, I believe I am OK with the coolant then.

 

If you religiously top up the coolant, you will eventually overflow the catchment tank. Not a huge deal, but not desirable either...

I also top mine up parked in the driveway, which has about a 10 degree upslope. This seems to help with the bleeding (or at least, I've never had any issues).

After coolant refills I monitor mine daily for a week or so to ensure trapped air hasn't come out and lowered the level or leaks haven't sprung up, but after that go for long periods without peeking in there.

Cheers,

- Will