How Do I Get the Water Out When Changing Antifreeze?

Forgive me for posting this twice but I posted it in the other group by accident -- I intended to post here. =============================

I've had this problem with most of the cars I've owned.

When you read instructions for changing antifreeze they almost always say something to the effect that, "It's simple. Anyone can do it." Then proceed to give some simpleminded drain and refill instructions. Well, I've rebuilt engines and overhauled transmissions and repaired virtually every part of a car, but I don't find changing the antifreeze easy.

For me, the flushing part is easy -- I use one of those Prestone backflush gadgets that go on a heater hose. The problem comes replacing the antifreeze. When I open the petcock on the radiator I can never get enough water to drain out to allow me to replace enough antifreeze to create a 50/50 mix -- too much water stays in the block. As a hypothetical example, assume the cooling system capacity is 12 quarts. You need to add a gallon and a half of antifreeze to create a

50/50 mix. But, after draining all the water I can get to come out of the radiator petcock it will only take one gallon of antifreeze.

I don't understand why others don't have this problem, but I never see anyone mention it.

It's true, if you can find, get to and remove the block plug you can drain enough out, but the instructions never mention the block plug.

I often find it is rusted or seized to the point it won't come out, or it's in some godawful location and with the engine hot you burn you hands trying to reach it. I have a permanent scar the size of a quarter on the back of my hand where I touched he exhaust manifold while loosening the block plug about twenty years ago.

How do others drain the cooling system sufficiently to allow replacing enough antifreeze/coolant? (And, god help the people who buy prediluted antifreeze that requires you drain the system completely.)

Reply to
jim evans
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If you start the car with the lower hose off wouldn't the water pump remove a lot of it? It will only be running for a short time, so you won't have to worry about it overheating.

Reply to
m6onz5a

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You could also pressurize the system and the air should push it out. (remove lower hose first) :)

Reply to
m6onz5a

completely.)

Look.. Remove the lower radiator hose and the thermostat. Flush the radiator with a garden hose. Then put the hose in the upper radiator hose and flush the block.

If you flush copiously, you will get out everything that needs to come out.

It is absolutely BS that you must have everything surgically clean. Good antifreeze, nowadays, will mix with just about everything including DexCool.

It is cheap enough to refill the system with distilled water/antifreeze. Not absolutely necessary, but cheap enough.

In the past I have knocked out the Welch plugs when they were rotten, and have dug out the poop, stopleak,etc, by hand that would not flush. If your Welch plugs are rotten, this is a good time to change them.

But dont get rolled over a barrel. This is not brain surgery.

Reply to
HLS

We Corvair guys are advising on coolant?

On my 283 V8, the coolant won't run out freely unless the radiator cap is off. He could also loosen the Prestone cap to get better drainage.

Reply to
A Muzi

I have to say that I have never had this problem in all my cars... about 30. Hope you are removing the cap when you drain it. Try running it for a few seconds. Park with nose down hill.

Reply to
Paul

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I don't see you offering any suggestions.

Reply to
m6onz5a

If the heater uses a valve in the heater hose (as opposed to running coolant through the heater core all the time and just diverting air through/around it) make sure the heater is on full.

nate

Reply to
Nate Nagel

Forget about getting all the fluid out of the block. What you really want to do is to make sure that whatever is left in there is fresh water.

Drain the old coolant at the bottom of the radiator. Close the drain plug, refill the radiator and run the engine for a few minutes (until the t'stat opens and the coolant starts to circulate. Open the heater circuits while doing this). Stop. Drain again (from the bottom of the radiator). Repeat until the coolant looks clear.

Once you are satisfied that the old antifreeze concentration is sufficiently low. Drain once more and refill the radiator with the calculated amount of new antifreeze required to make the correct mixture given the total engine coolant volume. Top off with water if there's still room left.

Reply to
Paul Hovnanian P.E.

forgot to mention, if one of the block drains is accessable without removing stuff (like the starter) if you can get the plug out a petcock is often the same thread. or just go to the hardware store and get a brass pipe plug.

nate

Reply to
Nate Nagel
[snip]

Yeah. How _DO_ you guys get all the old air out of the engine?

Reply to
Paul Hovnanian P.E.

The cooling system flush machines put adapters into the upper hose. When the thermostat opens, the old comes out and the new goes in. You're right about the rad not holding 50% of the coolant. Maybe in the old days. About the only engines I can get the block drains out are the GM 3100 and relatives. They've got a nice 9/16" head on them. I save the ones from blown engines for race motors.

Reply to
Steve Austin

I'll show you right after I change my blinker fluid.

Reply to
m6onz5a

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