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Incomplete coolant draining

Old 06-10-2019, 09:56 PM
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Default Incomplete coolant draining

I'm trying to decide if I need to drain the coolant on my 85 C4 again. I drained and removed the radiator, allowed the lower hose to drain, and then drained more coolant by removing the block to oil cooler hose. Since I'm a noob I thought that would drain everything, but now I'm reading that I was supposed to also remove the knock sensor. The problem is I flushed the block with plain water, and I filled up with premixed 50/50 coolant when I was done. So if there was still water in there when I filled back up then my 50 / 50 ratio is off.

I ended up needing 2.5 gallons to fill it up, I'm thinking that's still a few quarts shy of the total capacity so I probably did have substantial water in there (I don't think it's air because it's running at perfect temps even when stopped).

Should I go ahead and drain everything, including pulling the knock sensor?

Last edited by SinisterAgaric; 06-10-2019 at 09:56 PM.
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Old 06-10-2019, 10:10 PM
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You did way more than 90% of people do, and I think your over all dilution of antifreeze/water will be fine unless you live somewhere extremely cold and park outside.

What you didn't get was what's in the heater core (~1/2 qt) and what is in the passenger's side of the block. Probably less than a gallon, total.
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Old 06-10-2019, 10:38 PM
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That doesn't sound too bad. If anything I might drain a small amount and add in less diluted coolant to bring the ratio up.

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