I had a chuckle at 18 - 22 deg being pretty warm, here in Oz most folks are reaching for their winter woollies at 18 deg!
Not me most here think I’m mad for thinking that’s comfortable tee shirt weather……must be my Scottish ancestry.
Given that the engine is a very snug fit in its bay and the fact that being hidden back there, offers bugger all air flow around it, means these things do retain shitloads of heat.
In order to help properly disperse this heat and reduce the heat stress on the engine, and any components in the engine bay that wouldn’t enjoy the heat soak, I fitted two small fans to the under side on the grill at the top of bay to push air out as the air flow is pretty poor, yes the is a fan that blows air in from outside sucking through one of the side vents but this airflow mostly just takes the path of least resistance and disperses out under the car without disturbing the hot air trapped in the upper engine bay.
I used some 12V fans from a quad bike, they look like bloody computer fans and probably that’s what they basically are, but as they are from a quad bike they should be pretty tolerant to mud, muck and water. They’ve been on there for donkey’s years and have given no trouble at all.
I wired them in with a relay that takes it trip feed from the in feed of the engine bay fan.
They pump out an amazing amount of heat!
This helps to keep the wiring insulation from baking hard, the electronic components from being cooked, reduces heat stresses on the engine itself and any plastic or rubber bits that might deteriorate over many extreme heating and cooling cycles.
I did a write up here some years ago, you might do a search of the archives.
Try here
In fact you should checkout the archives to gain the wisdom of the ages anyway…… mind you only take the wisdom on board, leave the stupidity behind.
And yes you Must fit a low coolant alarm, no ifs or buts will be tolerated, it is pure insanity to run these cars without one.
The cost of fitting one is insignificant in comparison to a cooked engine!….which is a fairly likely outcome if one isn’t fitted.
You’ll get no pity from me or anyone else with any sense around here if you don’t!
I use the Browns & Gammons low coolant alarm and can highly recommend it, but I do understand that there are alternatives, although I would avoid the nasty el cheapo type that involves screwing self tapping screws into the plastic header tank.
Remember the quality remains to be enjoyed long after the price has been forgotten.