[gomowgto]

Why are these capacities different? The 1967 owners manual under tempest says cooling system capacity is 17.8 qts.
The 1967 service manual for tempest V-8 says 20.5 qts.
I have a 1967 GTO, with heater, no A/C and a Harrison 3 core radiator.
That's a big enough difference to "make a difference when changing the antifreeze.
So which one do I follow??

[gomowgto]

Just noticed that the pics are too blurry to read. Here are some hopefully better ones. If you own both the 67 service manual, page 1-19, and the 67 owners manual, page 61, you can see them there. They are different.

[bdk1976]

I would go with the amount that results in the proper level of coolant in your tank after all air has been removed from the system. It may not be either of those amounts?

I don't know if I've ever measured out exactly how much coolant I put in an engine and have never had problems. I just use those listed #'s as an estimate as to how much I need to have on hand (~5 gallons in this case).

[60sstuff]

Originally Posted by gomowgto

I have a 1967 GTO, with heater, no A/C and a Harrison 3 core radiator.

Well, you learn something everyday. Never seen a 3 core in a ‘67 GTO.

I always thought “ALL” 1967 GTO’s came with a 4 Core radiator.

I’ve owned countless ‘67 GTO’s and seen 100’s more and they all have a 4 core.
Only exception may be a 2BBL. 400 GTO.

[gomowgto]

It's very possible that whoever restored this car over 30 years ago put this 3 core radiator in it, I don't know. What I do know is I've owned it almost 19 years, I'm running a 160 degree thermostat, and temps stay between 180-190 degrees all the time.
I just found it odd that there are 2 different capacity amounts. Maybe the difference is because of the radiator. A three core would obviously be less.

[Kenth]

From the 1967 Tempest/GTO Assembly Manual:

[gomowgto]

Sorry kenth, your attachment is unreadable, but I have the restoration manual. All I really want to know is how many quarts of antifreeze do I need to add. I flushed the system and the block. I did not remove the block plugs, antifreeze ruins engine paint. I was able to remove 10 quarts of fluid from the radiator and motor. I put 2 gallons of prestone in, and then topped it off with water. I just feel I might be 1 quart short on the antifreeze.

[Kenth]

Right-click on the image, open in a new tab, save to the desktop and then enlarge the image so that it can be read.

HTH