Flushing Coolant
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5th Gear
Joined: Jun 2008
Posts: 5
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From: Saratoga CA
Flushing Coolant
I have an '89 corvette. In reading the postings on this subject the consensus is to drain the block as well as the radiator. If I then refill the radiator with coolant and start the engine isn't there a concern about the block being empty of coolant until the pump can fill it up? Is it necessary to drain both sides of the block? Thanks
Safety Car
Joined: Oct 2007
Posts: 3,816
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From: :45 minutes from everywhere / E-I-E-I-O
The block DOES hold a lot of juice.
If your coolant is really fouled, then pull the block plugs. If you're just doin' coolant maintenance, then drain and fill with water, and drain again, maybe 3 times. Refill each time VERY VERY SLOWLY, cause it will be hot.
Put the hose on the heater core hose too, to force core jam out.
For final mixing, pour in pure coolant first, UP TO HALF OF THE STOCK COOLANT CAPACITY. Then top off with water.
Say capacity is 12 quarts, and you have maybe 5 quarts of clean flush water left in the block, that you can't get out.
Put 6 quarts of pure coolant in first, then fill with water. 6 coolant, 6 water. Don't fill with 50/50; you don't know what mix you'll end up with.
If your coolant is really fouled, then pull the block plugs. If you're just doin' coolant maintenance, then drain and fill with water, and drain again, maybe 3 times. Refill each time VERY VERY SLOWLY, cause it will be hot.
Put the hose on the heater core hose too, to force core jam out.
For final mixing, pour in pure coolant first, UP TO HALF OF THE STOCK COOLANT CAPACITY. Then top off with water.
Say capacity is 12 quarts, and you have maybe 5 quarts of clean flush water left in the block, that you can't get out.
Put 6 quarts of pure coolant in first, then fill with water. 6 coolant, 6 water. Don't fill with 50/50; you don't know what mix you'll end up with.
Le Mans Master
Joined: Jun 2006
Posts: 5,642
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From: One day you're a Comet...the next day you're dust... Arkansas
Pro
Joined: Mar 2005
Posts: 666
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From: Walton KY
Or find a quick lube in your area that you can trust. I do cooling system flushes for $59.99 that will flush out radiator, block, and heater core. I will take a garden hose to flush heater core for free if asked. If your coolant is really bad (and you came to my shop) I would flush with hot water first, then coolant.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
The block will fill up as you put coolant in the radiator. If you are really concerned, keep track of the amount of coolant you add vs stated capacity which is about 14 quarts 91 and older, 17.8 quarts 92 and newer. You can always remove the serp belt and turn the WP by hand if you want.
I just dropped in a new ZZ4 block into my 85 (BONE DRY) and had no issues adding coolant.
I just dropped in a new ZZ4 block into my 85 (BONE DRY) and had no issues adding coolant.
