Changing the antifreeze/coolant

facade wrote: tbh, anti-freeze lasts pretty much forever, it is the anti-corrosion additives that get used up, so renewing 75% of the antifreeze should be fine.

I tend to go this route, Being lazy about antifreeze I just work out how much is needed to get the ratio right for the whole system, suck out what is needed to make room and pour neat in.

Someone would probably comment "well just use concentrated coolant and control your own mix". I would gladly, but almost all Japanese engines require coolant chemistries which are specific to them and quite contradictory to most European coolants, and having anything Japanese in my country is like having a space ship. It can be quite an endeavor to find ordinary parts for Japanese cars, let alone dedicated coolants. The only Japanese-suitable coolants (non-silicated, phosphated OAT coolant types) which I can find here are already pre-mixed, no concentrates.

My Junior was the most awkward to get information about being JDM only but my other Japanese imported cars Pajeros, Rav4 etc. (Ie, spaceships) were no problem I suppose because there are UK equivalents here. Maybe I am a Philistine (anti intellectual I confess) but I just use whatever is on the shelves.:blink: :whistle:

I figured out the same solution for the issue of getting a diluted final mix when doing the final pouring with an already 50/50 pre-mixed coolant.

The simplest solution is to drive for a day or two with that (so that the newly poured 50/50 pre-mixed coolant mixes with remaining water in the system), and then drain out a liter or two of that mix and fill the missing part with more 50/50 pre-mixed coolant. This should bring the total mix closer to the 50/50 ratio, probably somewhere around 40/60 (coolant/water).
This is not ideal solution, and it wastes pre-mixed coolant, but it is at least dead simple.


I have just one remaining concern when flushing:
The manual does say that the system should be flushed with (preferably distilled) water in a few iterations, until clear water drains out. It says that in each iteration, you need to pour water in the radiator, run the engine until the top radiator hose (and thus the cooling system) get hot, stop the engine, drain. Then refill a new load of water and repeat the iteration.

Now, I am worried if pouring cold new water in a hot empty radiator is healthy for the radiator? It will produce sudden temperature shock changes, and I don't thank that any metal, plastic and rubber parts of the cooling system like such shocks! But on the other hand, I certainly don't fancy pre-heating the water on a stove !!

There's a lot of over thinking going on here.

Take the bottom radiator hose off with a new jubilee clip ready to replace the factory spring clip. Have the heater on hot before you start.

Re-fill with red 5 year anti-freeze to at least 50% and whatever water you like.

Run it up with the radiator cap off until it's hot and keep squeezing the radiator pipes to expell air.

Job done. Have a cup of tea and a Hob Nob.

Kirkynut

kirkynut wrote:
Job done. Have a cup of tea and a Hob Nob.

Kirkynut

Nice and easy.

helijohn wrote:

kirkynut wrote:
Job done. Have a cup of tea and a Hob Nob.

Kirkynut

Nice and easy.

It is John. One of the easiest cars to change the coolant on but it's being made into a major operation!

Kirkynut

I see a few of you mentioning 50/50 of coolant/water ? Water is the coolant? The anti freeze is not a coolant, just a corrosion inhibitor and an anti freeze. The best conductor of heat is water, nothing beats it !