It is time to change the coolant, 75,000 (actually ~78,000 oops!). How do I drain the coolant from the block? My plan is to drain as much as I can, flush with a Prestone Flush and fill adapter and my garden hose, drain the water and refill with 50/50 coolant and water.

 

You cant really drain the block without removing freeze plugs. I just flush it and the old stuff comes out when the flushing begins.

 

I remove the heater hose from the back of the intake. I remove the thermostat. Open the reservoir tank.

Open the radiator drain, and let it drain. It will take about half of the block's coolant with it.

Put a hose into the reservoir tank and turn it on.

Wait until the water runs clear out the back (and front) of the block. Leave the hose running.

Leaving the thermostat OUT, bolt back on the thermostat housing and radiator hose.

While there's still water pouring out the back of the intake, reconnect the heater hose. Don't clamp it yet.

Start the engine. With the hose running into the resevoir. With water pouring out the bottom of the radiator. Whatever coolant is left will immediately be mixed up with the fresh water, because the thermostat isn't there. Maybe run it a minute like this. If you're still getting crappy water out of the radiator drain, keep doing this until it runs clear (doesn't take long).

Turn it off, let the radiator drain again, remove the thermostat housing, and remove the back heater hose again. Close the radiator drain.

Look in the owner's manual for the coolant capacity. If you're doing 50/50, divide it by half, and pour that much 100% antifreeze into the reservoir. You should be able to get half the total capacity into the radiator and engine before it starts coming out the thermostat housing and back of the intake.

After you've gotten all the coolant in, pour fresh water in until it comes up to the thermostat hole, or the back of the intake (whichever is first). Connect whichever one was first, if it's the back of the intake, connect the heater hose and clamp it. If it's the thermostat, install a new thermostat and o-ring, and install the housing (not the rad hose yet). Repeat until it comes out the other hole, and reinstall the housing or put the hose back on. Not the rad hose yet.

Continue filling until it comes up the full mark on the reservoir. If your thermostat has a bleed hole, it will start running out the thermostat housing first. When it does, install the radiator hose and clamp it.

Keep filling.

Run engine until "normal" operating temp, and keep filling with fresh water until it doesn't go down anymore. Take a drive, keep an eye on it for a few days, and you're done.

The key is, flush completely, then start filling with half the full capacity of 100% pure coolant, and then just fill the rest with water. That way, you'll be 50/50 overall, without mixing.

 

By the way, I use a propylene glycol based antifreeze, so it's "somewhat" safe to just pour on the ground, leave in open containers (doesn't kill animals), etc.

Never a problem down to near 0 degrees, never a corrosion problem (exactly the opposite, as a matter of fact), etc.

 

And if you are using the old stuff? How do you contain all of that flushing? This is my delimma. I have a block heater to install and while I was at it, figured it would be a good time to change out the antifreeze.

As a side bar: When I told my wife she said "Summer is comming - why do you want to change the anti-freeze?" I couldn't help but laugh!

 

I'm not telling...

 

I don't know what your domestic water is like, but I would not allow any tap water in my motor. I would only use purified or distilled water. I have seen much bad corrosion in aluminum motor parts caused by tap water.

 

Well, on Long Island, the water is so soft it doesn't have to be treated/filtered or anything else. So, I can use it for coolant mix.

In other parts of the country, it can be pretty icky

 

I would never think of using TAP water in a rad in WA ST. I just threw a rad in my rig and made sure to flush it with distilled and then drained and filled with coolant and distilled. The manufacturer of the rad even states that using tap water will void the warrantee. I keep the receipt for the water just in case.

 

I drain the radiator into a big pan and then pur the pan into a 5-gallon bucket. I take the plug out of the back LH side of the block and drain what's left on that side of the block into the pan. The RH plug isn't easy to get to, so I ignore it. Replace the plug, pour in half green stuff and half distilled water. I do this about every 30,000 miles so I'm not worried too much about leaving "old" antifreeze in. This method drains 5 of the 7.5 gallons. I pour the old antifreeze solution down a commode (which is the environmentaly safe way to dispose of it).

 

There is a drain plug on each side of the block about center that is removed with an allen wrench. Make sure the allen is a tight fit as the plug is usually very tight. Once they are out, replace them with brass plugs that have a hex fitting that you can use a 6 point wrench or socket. Do not use brass plugs with an allen fitting or square drive. There is a potential for damage with these.