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Looking to replace it all

What I have to work with:

  • degassing tank cap is removable
  • air bleed at the thermostat
  • drain valve at radiator's bottom

Putting one hose back after having it taken off took me some two hours. And lots of sweating. If possible I would very much avoid them. Both hoses between engine and radiator are at a higher level than engine's lower half so I think the antifreeze just stagnates inside the engine block even when the thermostat is open (and the water pump not pumipng).

I loathingly thought about taking the non-thermostat-side hose off and slide in a wine racking hose in order to suck it out. Aside from my newly acquired hatred for car hoses I doubt that would work as the angles are impossible.

The engine in question is the 1.6 ddis (Multijet Fiat) engine - very tightly mounted on a Suzuki Vitara New car.

Watched some youtube videos.. .everything is so much easier on other cars!


Attaching a few pics from beneath the car, driver side. Does that oozing green paste smeared screw look like it holds antifreeze ?

First pic: I suspect is is the coolant drain screw

enter image description here

Second pic: More of what the cast iron block looks like; It is about double the size of the oil pan when seen from below.

enter image description here

Third pic: Another similar looking screw in the same block, not far away from the first one

enter image description here

1 Answer 1

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I think you're asking, "How can I get 100% of the coolant out of my engine so I can replace it with clean, fresh coolant?" If that's not your question, please stop now and edit your question so that it asks a specific question.

Still with me? OK, good, I'll answer the question that I think you asked.

As in all car maintenance, it's reasonable to simply follow the intentions of the manufacturer. If they did not provide a way to remove 100% of the old coolant from your engine, they must not think that it's necessary.

"Nay, this shall not stand!" you say? You want 100% of the old coolant out, just because? OK, remove the engine from the car, disconnect all hoses and bolt it to a 3-axis motorized engine stand so that it turns it all possible orientations. Switch the stand on rotate in all three planes like a rotomolder for a couple of hours over a spare kiddie pool, and I guarantee that 100% of the coolant will eventually come out of the engine.

Not practical? Hmmm, I agree. Are you willing to settle for almost 100%?

Suppose for the sake of this discussion that your cooling system holds 10 liters of coolant but only 9 liters come out when you drain it according to the manufacturer's intentions. That's a 90% exchange rate.

Simply change your coolant more than once, and run the car under load to full operating temperature between changes. Remember to run the heat when the engine gets hot so the coolant in the heater core gets changed too.

What will be the result? How close can you get to 100%?

e

You can keep going until you don't have a single molecule of old coolant left, just like homeopathic remedies, but only you can decide how far to take it.

But holy cow, you say, this can get expensive! And what about the environmental cost? I agree, but every obsession has its cost. It's up to you to decide what percentage is reasonable. Me, I stop at one change just like most people.

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  • You got it right, especially this - "If they did not provide a way to remove 100% of the old coolant from your engine, they must not think that it's necessary.". Thing is it is not 9 out of 10 liters that come out of the radiator but 2.5l out of... 7.2l (owner manual says) / 6.2l (repair manual says - which is pretty crappy). Please also see my edit
    – kellogs
    Commented Aug 9, 2023 at 18:20
  • @kellogs Yikes, that's awful! And the repair manual doesn't give a specific procedure such as opening a vent on top of the engine or showing which plugs to open? Sorry to ask the obvious but it has to be asked!
    – MTA
    Commented Aug 9, 2023 at 19:28
  • @kellogs If there is no other way, consider the method I mentioned. It’s not as crazy as it sounds: there are “coolant exchange machines” in use today that do exactly this on a hot, running engine, but they use smaller increments to reduce the amount of coolant needed. If your system holds 7.2 liters and you drain and replace 2.5 L at a time, 5 exchanges give you 88% replacement costing 12.5 liters of new coolant and 7 exchanges give you 95% pure new coolant costing 17.5 liters. Assumes thorough mixing in a hot engine between changes. Sorry I can't identify plugs in your images.
    – MTA
    Commented Aug 9, 2023 at 19:30
  • 95% is good enough... it will take me a week or so :-) Yes, the repair manual only talks about drain/refilling the radiator. No mention on the rest of the circuit
    – kellogs
    Commented Aug 9, 2023 at 20:23
  • 1
    @Pᴀᴜʟsᴛᴇʀ2 Actually coolant does go bad. The anti-corrosion additives are consumed. Sediment, in traditional coolants, are largely the additives (silicates) coming out of solution. In trucks with coolant filters, additives are regularly monitored with test strips and replenished by adding an extender, or they have filters impregnated with extenders that gradually dissolve into the coolant.
    – user71659
    Commented Aug 10, 2023 at 0:35

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