I've had very good driving in my 1963 3.8 FHC since last I checked in, with the rear suspension undergoing a (dear) full overhaul, which sorted out the weird creaking I had on throttle.
Now, some advice required. PM or post here. I felt something bobbing about inside my radiator header tank under the opening and upon investigation there were several large hard brittle flakes (like big hard corn chips) floating about inside the radiator header tank. I shall try to attach a photo of the culprits. Apparently this is epoxy. It seems someone had at some point lined the header tank (no doubt against a leak or two) with the stuff and it has now worked its way loose. I've had coolant leaks on and off and various seals and plugs and hoses replaced. For quite a while, I've not lost any coolant.
Now, the practical issue is that I am using Evans waterless coolant. I won't revisit the debate whether that's the best idea or not - it was what we went with some 3 years ago. Initially, I had cooling issues as fans and relays were not working properly. I have had no cooling issues for more than two years. Ironically, I used to measure the Evans level by testing that it was wet in the header tank above the "first horizontal plate" - and this "first horizontal plate" was in fact not any design feature of my header tank but rather a solid flake of this stuff nestling some inch or so under the opening of the header tank. It is probably prudent to flush the system, replace the header tank, and replace the Evans. As for the proper header tank, it seems from Clausager's guide and from Haddock and Mueller's guide that the general substitution from back-corner entry for main hose design to side entry for main hose design was done relatively early on (Clausager reckons somewhere in 1961 and Haddock and Mueller reckon designs were interwoven until about March 1963), which means mine (Dec 1963) should be the side entry design if I am to replace it. The current one is the side-entry version. Presumably aluminium (I see there's a brass version too).
But now, with everything having worked so well with the temperature and the Evans for two years despite the corn flakes in the header tank, should I get the Evans flushed and replaced and header tank replaced, with the attendant costs and risks of messing with something that has been working well? Or should I just leave it as is, with all this stuff floating about the header tank and maybe bits of it in the radiator tubes or who knows where else? Advice sincerely appreciated.
