Coolant capacity SB AC

[John H.]

I need to know how much coolant should be added when flushing system.
Coolant container Prestone Low Tox (animal safe) states to use 1/2 to 2/3 coolant with the remaining as water. WHAT IS THE 2/3 COOLANT AMOUNT? How many gallons etc? Of coolant should be used?
I know I can just mix it coolant and water, before putting mixture into
the radiator, however I dont; know how many gallons of coolant I need to
purchase. Any help here.

[Terry M.]

Re: Coolant capacity SB AC

John,
The coolant system capacity for your car (it would be nice if you told us what year your SBC is although it is probably the same for all 1970-72 w/C-60) should be in your owner's manual and/or your copy of the CSM (Chevrolet Service Manual). I have neither here at work, so you will have to do some looking, or you can wait until someone else who has access to their library answers.

[John H.]

Re: Coolant capacity SB AC

Sorry for the details It is a 1972 manual transmission.
Thanks Big John

[John H.]

Re: Coolant capacity SB AC

It's a 1972 manual transmission.Thanks Big John

[Larry M.]

Re: Coolant capacity SB AC

I need to know how much coolant should be added when flushing system.
Coolant container Prestone Low Tox (animal safe) states to use 1/2 to 2/3 coolant with the remaining as water. WHAT IS THE 2/3 COOLANT AMOUNT? How many gallons etc? Of coolant should be used?
I know I can just mix it coolant and water, before putting mixture into
the radiator, however I dont; know how many gallons of coolant I need to
purchase. Any help here.

John:

What year car and what engine?? My 1967 327/350 HP with factory air has 19 quarts total coolant capacity. 2/3 of that is about 12 quarts.

I would add 2-1/2 to 3 gallons of antifreeze and the rest distilled water to a dry system. Then test for % antifreeze a few days after running the car, and readjust as or if needed.

Your owners manual has the system coolant capacity. The GM service manual for your year car also should have this number.

[Patrick H.]

Re: Coolant capacity SB AC

I usually keep an empty 1 gallon antifreeze container around just for this reason.

I mark the "full" level on the side of the new one, then pour about half of it into the empty container. There are usually marks on the side, else they are not that tough to compare. I then fill each with distilled water to the level that matches the original Full level. I now have 2 gallons of mix, and go from there repeating until the system is full.

Yes, it is nice to know the theoretical capacity of the system but I find that theoretical and actualy don't always match in this case.

Oh, and as you can tell, I use the tried-and-true 50/50 mix rather than some other level.

Patrick

[John H.]

Re: Coolant capacity SB AC

Distilled water was mentioned as part of the answer.
Can anyone explain why to use distilled water etc...?

[Jim T.]

Re: Coolant capacity SB AC

If you flush your system with water you will probably have about two or more quarts of water in the block that will not drain unless you remove the engine block drain bolts. With my 70 350/300 having factory air I have always poured two gallons of anti-freeze in first then add water. Did not use distilled water until I learned of the benefits in using it.

[Roy V.]

Re: Coolant capacity SB AC

On page 67 of my 1972 owners manual, under specifications,the amount listed for the 350 V-8 is 17 quarts with a note to add 1 quart for cars equipped with air conditioning for a total of 18 quarts.
18 divided by 4 is 4.5 gallons, divide that by 2 and that gives you 2.25 gallons of antifreeze mixed with 2.25 gallons of water (50-50 mixture). I too have heard that you should use distilled water for this and I think that distilled water has had most of the impurities and minerals taken out of it that can clog up your cooling system making it less efficient. To be honest with you I have been mixing mine with tap water for years with no noticeable degradation, but I do flush the system and change the coolant every 2 years.
Hope this helps
Roy

[Gary C.]

Re: Coolant capacity SB AC

Hi John

Hope you are doing well.

For our south Louisiana climate a 50/50 mix will work just fine and I think the 2/3 mixture will offer no significant functional advantage and will just use more antifreeze. As Patrick outlined it is easy if you can pour half of your new gallon full strength antifreeze into an empty gallon container and then top them both off with distilled water. You then have two gallons ready to go into the cooling system. Most of the stores now offer gallon jugs of the already diluted mixture so you can avoid mixing it yourself if you want to go that route, my guess is it cost more.

Distilled water is preferable over tap water because many of the minerals in the tap water can contribute to all that junk you find in old systems. They will cool the same in the short term, but distilled water is much preferred.

If you did not drain the cylinder case your fill requirement will be significantly less than the quoted capacity. Just go get about three gallons and mix a couple of em up 50/50 and see where you are. If you do not use one of the gallons bring it the the chapter charity auction/crawfish boil and I will buy it. I always have need for some more coolant around here and always seem to be out just when I would like to get something done without a trip to the store.

Good to see you are tinkering with the old car.

Regards

Gary