I can't recall where I read but the article stated the best use for the pre - mixed 50-50 coolants was for partial drain & fill applications . That said , how much coolant would you remove at one time on a yearly basis to keep your coolant fresh and in proper working order ? Also , I assume you would do the partial drain & fill from the radiator petcock ? Thanks in advance !
Partial Coolant Drain Method For Yearly Maintenance ?
- Thread starter ChrisD46
- Start date
Basically you open the petcock ( if the vehicle has one) and drain the entire contents of the radiator and possibly the coolant jug of it was designed to drain with the rad. The engine will still contain coolant. You then replace the volume with 50/50. Some folks talk about block drains but I’ve never found acceptable access to them.
The world is going to 10 year coolants. I presently use 5 year coolants and flush and fill with concentrated coolant ( where it mixes with water in the block and comes out close to 50/50). There is no question the dealerships are going to pre-mixed 50/50 . Considering that the rad is usually about 50% of the total coolant, you might pick every 2 or three years as being equivalent to a 5 year flush and fill regime. Draining less than a full radiator volume, and also doing it every year would be over kill IMHO.
I helped a friend drain his Acura MDX. Just the rad emptied. The coolant jug did not. The bottom of that vehicle has so much plastic cladding that there was a small panel to remove to get at the petcock. It was like a small little pee hole to drain the rad. Sheesh.
The world is going to 10 year coolants. I presently use 5 year coolants and flush and fill with concentrated coolant ( where it mixes with water in the block and comes out close to 50/50). There is no question the dealerships are going to pre-mixed 50/50 . Considering that the rad is usually about 50% of the total coolant, you might pick every 2 or three years as being equivalent to a 5 year flush and fill regime. Draining less than a full radiator volume, and also doing it every year would be over kill IMHO.
I helped a friend drain his Acura MDX. Just the rad emptied. The coolant jug did not. The bottom of that vehicle has so much plastic cladding that there was a small panel to remove to get at the petcock. It was like a small little pee hole to drain the rad. Sheesh.
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I'm sure the amount that comes out varies from car to car, but it's probably around half? So if the coolant was "completely used up" it would now be 50% new after a drain and fill. If it wasn't completely used up, it would then be 60 or 75% of new, something like that. Which IMO is good enough, it's not like it has to be 100% pristine to work--presumably, it would have a 5yr/100k lifespan for a reason, if that was the "used up" mark then changing half of it every year would mean it would never drop below 50%, as it'd never get there.
Or else leave a 10 year coolant in for 5 years, drain the rad and add a premixed 50/50 10 year coolant. Good as gold. See if you still own the car after 10 years. If so, do a flush and use concentrated coolant, if it still exists 10 years from now. 
This is Honda's recommended practice for coolant now as well.
I've joined the ranks of people just doing radiator drain and fills. One just has to decide when to do the first one, and then subsequent ones. My guess would be to do the first one at 1/2 to 2/3 the recommended interval, +/- a bit of time depending on mileage. I.E., 10 year coolant at 5 - 7 years +/-, then every 2 or 3 years afterwards, . It's such a simple and quick procedure compared to flushing the system. This assumes you had the car since new or are aware of the maintenance on a used car.
Don't forget that you can still use the concentrate (cheaper) and premix it yourself with distilled water.
Don't forget that you can still use the concentrate (cheaper) and premix it yourself with distilled water.
Aren't some newer cars getting harder to bleed air out of them (unless you have those special (but inexpensive) funnels) ?
Me too. Bro's '07 Odyssey and nabe's '10 Accord both drain almost exactly a gallon via the radiator petcock.
Must be magic.
To Hall: Yeah. Without seeking cooling system info I've stumbled upon a lot of, "How do I burp my_____" threads. Shoulda kept notes.
And, as usual, descriptions of scenarios involving trapped air come with panic toned warnings.
Don't get me wrong; I sure don't want to fry an engine.
And what about those "vacuum coolant installers"?
Must be magic.
To Hall: Yeah. Without seeking cooling system info I've stumbled upon a lot of, "How do I burp my_____" threads. Shoulda kept notes.
And, as usual, descriptions of scenarios involving trapped air come with panic toned warnings.
Don't get me wrong; I sure don't want to fry an engine.
And what about those "vacuum coolant installers"?
Some cars have small high point bleeder lines that have a continuous flow to the expansion tank. As long as that is open and flowing, any air is bled automatically. Caddy Northstars all had that. It came off of a hollow bolt in the throttle body.
Most coolants are 10 year 150k mi now.
So, I would just do something every 5 years / 75-100k mi.
For complete change:
I would do 2-3 drain and fills with pre-mix.
Or for concentrated: 2 drain and fills with distilled water, then whatever it takes to get the mix right. 1-1.5?
And yes it is best to have the large funnel to burp the system. They can be had for $20-30, no big deal.
So, I would just do something every 5 years / 75-100k mi.
For complete change:
I would do 2-3 drain and fills with pre-mix.
Or for concentrated: 2 drain and fills with distilled water, then whatever it takes to get the mix right. 1-1.5?
And yes it is best to have the large funnel to burp the system. They can be had for $20-30, no big deal.
The LS engines in the Chevy trucks do not have a petcock nor a radiator cap. The coolant tank is a flow through circulating design, or at least it was on my 2008. The coolant tank drains with the rad. You drain the rad by taking off the lower rad hose and fill through the top of the coolant tank. The coolant tank is pressurized when at operating temperature of about 210 F.
After flushing with water, filling the rad and coolant tank with concentrated antifreeze got me to about 60% antifreeze overall which is what I like in case I need to drive to Edmonton in the winter ( God forbid).
After flushing with water, filling the rad and coolant tank with concentrated antifreeze got me to about 60% antifreeze overall which is what I like in case I need to drive to Edmonton in the winter ( God forbid).
*My thinking is that for a new car filled with 5 year / 100K mile coolant I would do the partial drain & fill every 2 to 2.5 years and be relatively safe .
Once a year, quick drain and fill. Keep it simple.
but withe 50% used coolant and 50% new, you would now have 7.5 years...Or else leave a 10 year coolant in for 5 years, drain the rad and add a premixed 50/50 10 year coolant. Good as gold. See if you still own the car after 10 years. If so, do a flush and use concentrated coolant, if it still exists 10 years from now.
Sorry but that is both totally unnecessary and a fine waste of money. Modern coolant's (which dominate the market) have service intervals of 10 or 5 years or even more. For example Toyota's SLLC has a service interval of 12 years so changing it yearly is like going from changing your oil every 6 months to changing it twice a month. A simple drain and fill of the radiator is what basically all auto makers now recommend for as a coolant change, so you're not somehow cutting corners or saving time with a drain and fill.
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Yes, but that 50% used coolant was supposed to last 10 years anyway.
I just pull the plug on the radiator. The heads and some of the block will drain down to about the water pump and I don't worry about what's left in the block. It was nice in the past when blocks had drains and they were easy to get to but I think yearly maintenance is a little excessive.
EDIT: when draining/filling be sure to have the heater temp control on full hot. It makes it easier to get the air pocket out of the system.
EDIT: when draining/filling be sure to have the heater temp control on full hot. It makes it easier to get the air pocket out of the system.
Not a waste of money when you have 5 spare jugs of coolant sitting under your bench that are left overs from previous jobs.
It’s a waste of time then. Donate them or use them on family/friends vehicles.Not a waste of money when you have 5 spare jugs of coolant sitting under your bench that are left overs from previous jobs.
There is absolutely no reason to do coolant drains annually.
I've been doing a partial drain on my old E-150 for a very long time now. Years ago I would reverse flush it and go overboard thinking back. Every 5 years I open the drain on the radiator [cold engine] and drain it. Once it is drained I pinch the upper and lower radiator hoses and run water via the garden hose through the radiator until the water runs clean. I let it drain remove the hose pinching pliers and fill with green concentrate A/F mixed with 50% distilled water. Burp it, make sure it's full, re-check it in a day or so and call it done. The radiator and heater core are OE and the radiator still has no scale in it, so it appears that method works.
