Completely draining 1974 Eldorado radiator and engine block

[motard]

I want to completely drain my 1974 Eldorado radiator and engine block. When I drained only the radiator, I got out about 3 gallons of coolant.  The car should hold 5 3/4 gallons of coolant. What is an easy way to get the rest of the coolant out of the engine block? 

[Big Fins]

This may sound crazy, but I used a leaf blower with the nozzle into the thermostat opening to blow out any remaining coolant/flush. Then did the same with the heater core. Also blew it through the radiator with the hoses disconnected. Also removed and flushed the coolant recovery tank.

When you refill, take your time to get all the air out. When it reaches operating temperature and you shut it down and it cools off monitor the overflow bottle. If the cap is operating properly, it will draw in any needed coolant. But keep an eye on it for a while while it 'burps' any air trapped in the high spots.

[Mike Josephic CLC #3877]

I have a 1973 Eldorado (owned since new) and this is my method.  I don't remove the radiator hoses.

If you want to properly flush and drain all of the old coolant (as well
as the accumulated crud) you have to remove the block drains.  There
are two brass pipe plugs (one on each side) just above the oil pan on the block.  They are easy to find.

Once you remove those, you can put a garden hose in the radiator
and run the engine with the radiator petcock open and you will see
that after a few minutes the water will run clear.  If you've never done
this you'll be amazed how much rust and crud comes out of the block.

Mike

[TJ Hopland]

My question was going to be why?  Removing crud vs just a change vs some kind of storage would have different answers.

Leaf blower is an interesting idea I had not thought of.   The vacuum refill systems do work and are not that expensive.  Not required for stuff as old as we are talking here but still work and save time.  THey are pretty much required for most things made in the last 20 or so years.

[James Landi]

Quoting Mike here: "this you'll be amazed how much rust and crud comes out of the block."

Radiator scale and rust in the water jackets kill many engines and turn beloved old cars to junk.  Thorough descaling of the radiator and flushing of the engine's water jackets is a must.

[Jeff Rosansky CLC #28373]

He is asking about a full drain so I know this is a little off topic.
But, I pulled out the thermostat, unhooked the heater core return line at the radiator and put it over the side into a big trash can (saying that in case anyone from the EPA is reading this). I then put a hose in the radiator with fresh water. Started the car and let the water pump do the work. Absolutely amazed at the amount of crap that came out.
Then I drained the tap water from the system,and changed the hoses and added the thermostat.

[Lexi]

Quoting Mike here: "this you'll be amazed how much rust and crud comes out of the block."

Radiator scale and rust in the water jackets kill many engines and turn beloved old cars to junk.  Thorough descaling of the radiator and flushing of the engine's water jackets is a must.

James is correct. Also, everyone should use anti-freeze mixed with deionized water, (or distilled water as a second choice). This further reduces the corrosive effects that running straight water in your cooling system will cause. Fresh anti-freeze will not encourage rust and corrosion in the metallic portion of your cooling system. The deionized water it is mixed with should have all of the minerals removed from it; in contrast untreated water can add to your scale build up due to the mineral content present. Even living in the desert I would still use a mix of anti-freeze and deionized water. Distilled water is a good second choice but I believe it is not as clean as deionized water is. Could be still some junk in it. On the down side, improperly mixed anti-freeze can cause overheating so it should be fresh and mixed to the proper proportions; then changed every 2 - 5 years with a flush. Clay/Lexi

[dn010]

It's easier to buy pre-mixed antifreeze and not worry about having to add water.

[Lexi]

It is, but it is also a lot more expensive to buy pre-mixed-at least up here. With what de-ionized water you may have left you can keep to top up your wet cell battery if so installed. Clay/Lexi

[dn010]

I guess it must be different up there. Regular pre-mixed antifreeze is cheaper here and the only reason I know, ironically, I just had to get some for one of my cars that is receiving a rebuilt engine over the weekend. I paid $6.88 a gallon and concentrate was $10.88/gallon, not counting the water.

Even if pre-mixed was more expensive, that would not stop me. Not only have I already spent bundles of money on these cars - as time goes on, I am finding more and more that it is personally easier to pay a bit more for ease of use. Thankfully, the pre-mix takes a little break on the wallet here.

[Lexi]

Last I checked, buying pre-mixed can be up to 4 times as expensive-give or take based on the mixture you use. Ouch! Clay/Lexi

[Big Fins]

I never use pre-mixed. I always use the concentrate no matter what vehicle I'm working on. I tried the pre-mix one time thinking the same. It would be easier. It was like spending $7.00 for a gallon of colored water. I'll buy the concentrate and distilled water.

[TJ Hopland]

It comes out pretty darn close especially with how much everything else cost these days.  Using the above prices $10.88+$2.00ish for the water gets you 2 gallons so $6.44 per gallon vs. $6.88 for the premix so its not cheaper unless fancy water cost more than $2.  You could easily burn that $0.44 in gas if you had to drive to a different store for the water.

I buy the pre mix except for cases where for some reason I need to balance out the mix which does happen sometimes with used stuff I buy up here in freeze land. 

[motard]

Guys thanks for all the very good information on how to drain the coolant out of my radiator and engine block on my 1974 Eldorado.

motard

[Lexi]

Hope I did the math right, but in my case, here in the People's Republic of Canada, the cost differential is greater. Owning a Series 75 car with heaters including rear seat heaters (so a greater liquid volume); a 50/50 mix would cost $114 to fill, ($129 with tax), in Canadian dollars. Buying the concentrate, same brand, as well as the required amount of deionized water for the same mix would cost $81.00, ($92 with tax). A difference of $37. If I choose distilled water the cost would be $69 ($78.00 with tax), a savings of $51 when compared to the pre-mixed fluid. If I went the el-cheapo route and just used tap water it would cost $60 Canadian ($68.00 with tax), a savings of $61. So the costs have improved a bit since I last shopped during the pandemic, but there is still a significant cost differential at least here. These costs are from one Supplier. If you shop around, the distilled water in bulk can be found for a lot less which would further reduce cost. Clay/Lexi

[Big Fins]

I used tap water in my coffee pot for a while.

Imagine what it can do to a radiator and engine block? 

[Lexi]

Oddly enough, some of the minerals in tap water are good for you. But on a serious note, depending on where you live and where your water comes from, its mineral content can vary quite a lot. There was a time you could even tell the difference with respect to bottled soft drinks. Seem to recall that Coca Cola had a bottling plant somewhere in Ontario that was known for the better tast due to the local water. There is a place in downtown Toronto, (or used to be?), where you could buy bottled soda pop but from other countries. The taste did vary quite a bit. On this recent GN tour I did buy one Coke and thought that compared to ours that it was "off". But our Cadillacs don't like a high mineral content in their cooling system. Clay/Lexi

[TJ Hopland]

Interesting that the price varies so much since there can't be that many places making the stuff and I would assume in most stores you would be comparing the same brand and type. 

I would assume its all made in the same place?  So its not like one has higher transportation costs.  I would assume that if its not bottled and packaged where its made that the mix is made at the bottling stage.  Who knows maybe the concentrate comes from the factory even more concentrated and 'water' is added at the bottling stage for both types?

[The Tassie Devil(le)]

What is wrong with using unpolluted rain water?   That is from non-Acid rain areas or other contaminants.

Bruce.

[Big Fins]

What is wrong with using unpolluted rain water?   That is from non-Acid rain areas or other contaminants.

Bruce.

That would very few places in this industrialized world.