Coolant capacity for a 68 C20 396 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

northerngmc · 09-17-2010, 04:28 PM

I purchased a 1968 C20 with a 396 this past spring. I am getting ready for winter ( it snowed about 20 miles west of town yesterday!) and tested the antifreeze strength in the old girl. It tested -25 C or about -10 F, which isn't cold enough. So I need to drain some out to get the strength up to -40 or colder.

So while I am at it I might as well drain it all, flush it out with water and refill with new antifreeze and a new thermostat.

So any idea what the capacity is of the complete cooling system (rad, hoses, heater and engine)? The truck is a 1968 C20 with a 396 and Turbo 400 with a trans cooler.

I have done some searching and seen anywhere from 2 to 4 gallons. Anybody know for sure?

I want to know the capacity so I can add antifreeze after the flush without over diluting it from the water left in the system.

Also are there drains in the block of a 396? I was searching and someone mentioned draining the block using the drains when doing a coolant flush.

**GruntMoanCough** · 09-17-2010, 09:19 PM

The Haynes manual that I have lists 24 US qts. for your application.

Sammy · 09-17-2010, 10:12 PM

24 would be with a 4 core rad.

northerngmc · 09-18-2010, 10:48 AM

Thank yoiu very much, I believe it is a 4 core radiator.

09-17-2010, 04:28 PM	#1
northerngmc Registered User Join Date: Jan 2004 Location: Whitehorse YK Canada Posts: 2,651	Coolant capacity for a 68 C20 396 I purchased a 1968 C20 with a 396 this past spring. I am getting ready for winter ( it snowed about 20 miles west of town yesterday!) and tested the antifreeze strength in the old girl. It tested -25 C or about -10 F, which isn't cold enough. So I need to drain some out to get the strength up to -40 or colder. So while I am at it I might as well drain it all, flush it out with water and refill with new antifreeze and a new thermostat. So any idea what the capacity is of the complete cooling system (rad, hoses, heater and engine)? The truck is a 1968 C20 with a 396 and Turbo 400 with a trans cooler. I have done some searching and seen anywhere from 2 to 4 gallons. Anybody know for sure? I want to know the capacity so I can add antifreeze after the flush without over diluting it from the water left in the system. Also are there drains in the block of a 396? I was searching and someone mentioned draining the block using the drains when doing a coolant flush. __________________ Blaine 59 GMC 9314 a.k.a. Whoopee 68 C20 50th Anniversary a.k.a. The Rat http://www.flickr.com/photos/northerngmc/ http://www.members.tripod.com/P-wee/index_032.htm 1.61803 is one H of a lot better than 3.14159, no really it is!

09-17-2010, 09:19 PM	#2
GruntMoanCough Registered User Join Date: May 2009 Location: Pemberton, BC Posts: 1,075	Re: Coolant capacity for a 68 C20 396 The Haynes manual that I have lists 24 US qts. for your application. __________________ My goal in life is to be as good a person as my dog already thinks I am - Unknown

09-17-2010, 10:12 PM	#3
Sammy Registered User Join Date: Apr 2000 Location: Bonne Terre, Mo Posts: 3,005	Re: Coolant capacity for a 68 C20 396 24 would be with a 4 core rad. __________________ '69 Chevy Long Fleet & '71 GMC Short Step & Project "ODD BALL" "You can wash a pig, soak it in most expensive perfume. In the end it is still just a pig." ODD BALL build thread http://67-72chevytrucks.com/vboard/s...d.php?t=478629"

09-18-2010, 10:48 AM	#4
northerngmc Registered User Join Date: Jan 2004 Location: Whitehorse YK Canada Posts: 2,651	Re: Coolant capacity for a 68 C20 396 Thank yoiu very much, I believe it is a 4 core radiator. __________________ Blaine 59 GMC 9314 a.k.a. Whoopee 68 C20 50th Anniversary a.k.a. The Rat http://www.flickr.com/photos/northerngmc/ http://www.members.tripod.com/P-wee/index_032.htm 1.61803 is one H of a lot better than 3.14159, no really it is!



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