But it loves to over heat

It's the cost that's the killer.
IF you could get it out cleanly, you could get maybe 1/3 out by draining the rad, the next 1/2 will go all over the place when you take the thermostat out, and there will be 1/4 in the bottom of the block.
So, you may save 1/2 of it if you are lucky. Ok, it lasts for 'life' and it would cost you £40 if you used genuine coolant anyway..

If you believe the marketing then water-wetter will do the same (reduce cavitation and hot-spotting) as waterless anyway but at a fraction of the price.
I use it in my own truck and my own jobs but only because I mix up 50L of coolant at a time and chuck a bottle of it in there if I have one around.
I would not be to worried about running coolant without it if I did not have it to hand.

I do always use distilled water though as that stops a lot of crap building up in the engine and also seems to do a lot less damage if you do overheat or blow the gasket.

I don't think there is any advantage to having a coolant that won't boil until 180deg as your head is going to warp long before that anyway..

As for the EGT, either WW or WL might lower the temps a fraction as if they can reduce hot spots in the head then they should be getting the heat out of the head quicker. In turn the head itself will be a little cooler so should have a cooling effect on the gas as it flows out of the head.
It ain't going to be much though

nice one, re the EGT i was thinking more from a temperature monitoring point of view

only if you are watching it all the time.
Ideally there would be a couple of temp senders on the head and one in the eg and there would be a bell that started ringing so you didn't have to watch them all the time.

I expect most of the issues are gaskets blowing THEN it overheats though.
Just driving around with one eye on the gauges and switching it off it if looks like it's running hotter than normal ain't going to save you .
Maybe if you are towing heavy or something then it might stop you cooking it as you can back off if its going up but the first that 90% of the drivers will know about it is when the water level drops below the top of the water pump and it stops moving it round. goes from normal to the red mark in 10secs or so.

aye right enough - having been through two engines in the old truck , I put the gauge in this one and seem to look at it every 8 seconds lol

Agreed there. I watch my EGT gauge whenever she's getting worked. You get to learn when it will be hot and just flick over to look at it as Basil says. It won't save you from over heating if you have a cooling issue but should in theory save that failed-gasket-causes-over-heating scenario. I never let mine go over 700 which is what I am informed is the safe max running.

Billy, on that note. Since my exhaust sheered (before the first box) she runs much cooler. In the region of 75-100 degrees cooler on the EGT gauge when being pushed. I have a 2.5 inch exhaust to go on so it will be interesting to see if the larger performance exhaust still allows it to run cooler than the standard one. Would you say these findings are consistent with what you know? I'm guessing the hot gases are simply escaping quicker. If this is indeed correct and if my new exhaust does the same, then a performance exhaust would be a very worthwhile mod for any one with a classic.

strange one but i cant get mine near 700, average running just about moves the needle, then again ive had a walkinshaw on since i have had it, made little noticeable difference when the cat was removed

What do you get on a motorway hill if you keep your foot down Mike?

tell you later, i need to take her ladyship to james cook hosp to get the cochlear implant tuned, will give it some load on the way back, theres a few good heavy hills

Well i cant get it to hit 600, theres some serious climbs and she was still hittin 90 from 40 in 5th, sorry i mean 70.theres a good long hill just outside middle bro, i gave up in the end because she was gettin close to an instant ban speed and still accelerting, will send you the bill for the fuel used

Is this on a motorway? Sorry to sound picky but mine won't go near 600 on any hills unless it's a motorway. More speed needs more fuel n all that. Speed is the key. I can tow a trailer up hill at 60 and she won't be over 500. But hit the same hill at 70 with no trailer and she'll go over 700. I have one hill that is a mile long in 3rd and 4th and she won't go over 500. Is your probe in the EGR blank? And it's all the way in? I want to get my exhaust on now and see how it compares to your readings.

Sorry just read that properly rather than speed reading.

a19 luke,its a 70 mph dual carriageway, lot of long hills, some these hills 70 was well behind me

yep fully inserted in the egr blank, so its fully in the flame

Can only assume your exhaust is playing a big role then? Soon see when I fit mine.

may not be the same as this one luke, its a walkinshaw sports, two working pipes point out the back, was on it when purchased, when i checked they sell for about a grand !!!!, its always sounded deeper than any other L200 i have heard than a straight through, cat removal made no real difference nor did the apollo really, or not as much as i was led to believe they would

That would make sense to me. I'm sure your exhaust is better than the one I have bought with walkinshaw's name on it. That said I still have a 2.5 stainless to go on. I'm assuming yours a 2.5 stainless? Even if it flows better than mine, all we need from mine is continued lower EGT's than the factory exhaust to prove the point.

where mine changes a lot is the curves in it are more gentle than standard and after the one box it breaks out into a pair of tailpipes, yep stainless but i have seen better looking finishes on the main pipes, for me the advantages are tailgaters get two bores pointing at them and two orifices belching veg