I do it worm
Change coolant hot or cold?
- Thread starter Ed_Flecko
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There are some people that will remove the cap from the radiator and start the car and actually drain the coolant hot..crazy but true.
I usually do a 5 year flush with citric acid and then distilled and then a gallon of 70/30 mix topped by a 50/50 mix. So I will drain the flush hot and the second flush hot. But I generally use the lower radiator hose and won't do it if still under pressure.
My Accent is horrible for getting all the old coolant out. The Gen Coupe not so bad.
My Accent is horrible for getting all the old coolant out. The Gen Coupe not so bad.
I've got one passenger vehicle that you have to remove the radiator hose to change a battery. Though GM says the Dexcool from factory is good for 10 years @ initial purchase, then should be drained every subsequent 5 years and topped up?
I drain it cold from the petcock. Pop the upper hose free. Remove nose-fender strut over the battery. Swap battery. Reinstall all the removed bits. Open the overflow jug, (close the drain valve of course) and pour in 50:50 Dexcool premix. Wait for bubbles to stop, top up as needed to get to "Full Hot" and leave the cap off.
Start and let engine idle with climate controls set to full heat-vent. As the system burps through the steam tube bypass, top up as needed to maintain level at "Full Hot".
Shut it down, install cap. Walk away. Check it daily for next week, top up as needed when left to rest and fully cool, this time drizzling in just enough to reach "Full Cold".
Florida heat cooks batteries every 3~4 years around here, sometimes 5. So I just spill 'n' fill the coolant at the same time since I'm there anyway. I then recycle the batteries and coolant. No troubles doing it this way and *COLD*
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I spill 'n' fill oil hot though, after letting engine and tranny sit for half an hour. So I guess I'm still half crazy!
I drain it cold from the petcock. Pop the upper hose free. Remove nose-fender strut over the battery. Swap battery. Reinstall all the removed bits. Open the overflow jug, (close the drain valve of course) and pour in 50:50 Dexcool premix. Wait for bubbles to stop, top up as needed to get to "Full Hot" and leave the cap off.
Start and let engine idle with climate controls set to full heat-vent. As the system burps through the steam tube bypass, top up as needed to maintain level at "Full Hot".
Shut it down, install cap. Walk away. Check it daily for next week, top up as needed when left to rest and fully cool, this time drizzling in just enough to reach "Full Cold".
Florida heat cooks batteries every 3~4 years around here, sometimes 5. So I just spill 'n' fill the coolant at the same time since I'm there anyway. I then recycle the batteries and coolant. No troubles doing it this way and *COLD*
.I spill 'n' fill oil hot though, after letting engine and tranny sit for half an hour. So I guess I'm still half crazy!
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Well, it’s not like changing an oil filter every other oil change. It’s coolant, it’s clean. You’re replenishing the additives.
There‘s a lot of cars that don’t have accessible block drains. And some block drain designs are very poor and can snap right in the block (then you’re in trouble).
A simple drain and fill from the radiator every 30,000-50,000 miles...once every two years maybe after the initial factory fill of 100,000 miles, will never give you a problem. In fact, for those paying for this service (dealers or independent shops) are getting drain and fills (unless they have a coolant exchange machine). Nobody is removing coolant from the block in shops (and this is where someone will chime in and say they do it all the time). And I saw your post where you did yours...that’s great. It looks like it was accessible and easy to get to. But a lot of them aren’t.
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With long life coolant that lasts 100,000 or 150,000 miles, you don't need to replenish the additives. They last for 100,000 or 150,000 miles. That's why they are called "long life" and why the radiator still looks like new inside after all those miles.
Only on those Hondas do I do that, and even then, it doesn't seem to drain too much more coolant from the system using the block drain plug. I still go through the routine of drain, fill with water (distilled usually), drive 10-15 minutes until the thermostat opens and gets the water mixed with the old coolant, and drain again. Repeat 5 or more times until the water drains clear.
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If you read what I said...I said after 100,000 miles do it every other year (drain and fill). Two reasons...you’re not draining it all and after the initial fill some manufacturers recommend 50,000 thereafter.
I AM draining all of the old coolant out and leaving just distilled water. Manufacturers recommend 50,000 thereafter because they know few people with get ALL the old coolant out like I do. Doing it as I do, it's good for another 100,000 or 150,000 miles.
I just do a drain and fill with pre-mixed coolant every 5 years or 50,000 miles.
No flushing with water or concern about concentration.
Takes less than 30 minutes.
Every other time I change the thermostat and radiator cap.
No flushing with water or concern about concentration.
Takes less than 30 minutes.
Every other time I change the thermostat and radiator cap.
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That was my initial post said. A recap...
Not many people drain from the block...most do drain and fills. Initial factory fill is 100,000 miles. Second drain and fill is 30,000-50,000 miles later.
I've only done cold. Hot is asking to get burned badly. Like maybe emergency room, burn center badly. If you're doing a basic service, drain and fill is usually enough. Some cars are annoying when it comes to air pockets after coolant work. I've always only done a cold drain and fill and have never had coolant issues. Best of luck!
Agree, but for different reasons. I don't mind the scoldings. It's the scaldings that concern me most.
Agree, but for different reasons. I don't mind the scoldings. It's the scaldings that concern me most.
Don't yell at me when you start burning
Hahah I see what I did now.Agree, but for different reasons. I don't mind the scoldings. It's the scaldings that concern me most.
I just spent the day doing, among other things, 2 complete flush and fills on 2 cars. This was an efficiency task so I had two in rotation. Drain, fill, drive with heat on 10 minutes, each vehicle, wait 1 hour. Repeat. I found a 1 hour cooldown was sufficient to be no burn danger, but the coolant warm enough to extract nicely with the Mityvac and hopefully keep contaminants in suspension and flow nicely. I did about 5 iterations of pull and fills on each car, so it was an all day task with an hour cool down between iterations.
I went thru about 10 gallons of distilled water and ~5 gallons of concentrate coolant total.
I went thru about 10 gallons of distilled water and ~5 gallons of concentrate coolant total.
Warm...?
Not only that its under pressure so you will be terribly burned by ascalding hot liquid escaping under pressure. Coolant by its very nature transfers large amounts of heat, in this case to you skin.When you open a hot cooling system you lower the pressure and that coolant will flash boil on to you Look up coolant burns in google. If you want to replace coolant when hot make sure you have an ambulance or ER right next to you cause you'll need it. There's a reason why your owners manual and FSM say to check the coolant when the vehicle is cold.
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Absolutely agree on that too. I’ve seen someone get their hands covered in hot antifreeze. Must of sucked. They went to the hospital for it.