Flushed my coolant, have a question

[rainking1978]

I just hit 100k miles (all trouble free) and winter is comming so thought I would do some maintenance. I actually did the engine, transmission and coolant. Oh and some seafoam in the intake. I've been good with keeping up with it. I do the engine with mobil 1 5w30 synthetic with a puralator pureone oil filter every 5k miles. Transmission (toyota brand) and coolant (toyota brand) every 30k miles . Went to the dealer and bought the red coolant (not 50/50 mix). I drained and filled with distilled water. Ran the car till the fan kicked on and the heat was blowing hot air. I kept repeating that process until what was draining was clear. Took about 3 times. Now my question is, since the engine and heater core holds 50% of the coolant, it should have 50% distilled water now. So when I filled the radiator, I filled it with straight coolant. My thoughts were when it mixes with the distilled water that is in the engine and heater core, it would be a 50/50 mix. Are my reasoning's correct?

[rainking1978]

anyone?

[rainking1978]

Someones got to know.

[olbus]

I have no idea, but go buy an anti-freeze tester at a FLAPS and it will tell you how low the mix will go before freezing or boiling.

[JasonA]

This is why draining and refilling is the best option. If you've been doing coolant drains/refills every 30k miles up until now, there is frankly no reason to flush the system out or add straight water at this point. It'd be awfully hard to know exactly what you have in the car. You may have to buy a coolant tester and test what's in the radiator after the coolant has circulated through, so you can see what it has equilibrated to.

If I understand you right, and if your supposition that the engine and heater core holds 50% of the coolant is correct, you added straight water to half of the system, and have 50/50 solution in the other half. So all mixed together, you've got a 25/75 solution of coolant/water. Or, what you might be saying is after you got hot air from the system, you drained it again and filled it with more water?

I'd simply drain out as much as you can, fill it with 100% coolant. That would be a good first shot in the dark at getting a 50% solution overall. Run the engine for a few days, let everything get mixed up real good, and then test what's in the radiator (not the overflow tank, there's not much circulation in there). If the radiator shows more coolant than water, you'll want to drain out a half gallon or so and add water back. If there's more water than coolant, you'll need to drain some down and add straight coolant.

Then, from here on out, don't do any flushing or filling with straight water. If you always fill it with 50/50, you always have the correct concentration in it. Oh, and these cars don't have heater control valves like cars used to have. Coolant is always running through the heater core, so there's really no need to pay special attention to running the heat. Again, simply draining the coolant and refilling it on a regular basis, not to exceed what the recommended change interval is, is the best way to go.

[rainking1978]

Originally Posted by JasonA

This is why draining and refilling is the best option. If you've been doing coolant drains/refills every 30k miles up until now, there is frankly no reason to flush the system out or add straight water at this point. It'd be awfully hard to know exactly what you have in the car. You may have to buy a coolant tester and test what's in the radiator after the coolant has circulated through, so you can see what it has equilibrated to.

If I understand you right, and if your supposition that the engine and heater core holds 50% of the coolant is correct, you added straight water to half of the system, and have 50/50 solution in the other half. So all mixed together, you've got a 25/75 solution of coolant/water. Or, what you might be saying is after you got hot air from the system, you drained it again and filled it with more water?


I'd simply drain out as much as you can, fill it with 100% coolant. That would be a good first shot in the dark at getting a 50% solution overall. Run the engine for a few days, let everything get mixed up real good, and then test what's in the radiator (not the overflow tank, there's not much circulation in there). If the radiator shows more coolant than water, you'll want to drain out a half gallon or so and add water back. If there's more water than coolant, you'll need to drain some down and add straight coolant.

Then, from here on out, don't do any flushing or filling with straight water. If you always fill it with 50/50, you always have the correct concentration in it. Oh, and these cars don't have heater control valves like cars used to have. Coolant is always running through the heater core, so there's really no need to pay special attention to running the heat. Again, simply draining the coolant and refilling it on a regular basis, not to exceed what the recommended change interval is, is the best way to go.

Thanks. I filled it with 100% coolant. Not 50/50 mix. I will get a tester and go from there. Next time, I will just do a drain and fill with the 50/50 premix.