67-L71 big block coolant change

[David K.]

Hello to all; I have no idea how long the coolant has been inside my 67-L71. Car was restored in 2010. Want to change out with Zerex 50/50 mix. Is this coolant appropriate? Also, I have never changed coolant on a big block....and I don't see a drain cock at bottom of the radiator.... as per my previous small block cars. Can anyone please run me through the process?
Thanks in advance.

[Duke W.]

Re: 67-L71 big block coolant change

50 to 60 percent blend of Zerex G05 and distilled water... capacity is in the owner's manual and other docs, close to 20 quarts. Open the block drain plugs located above the pan rail about midway along the length... don't know why the radiator has no drain provision. Is it aftermarket?

Duke

[Larry M.]

Re: 67-L71 big block coolant change

Agree with Duke..........use Zerex G-05 and distilled water. Perhaps your radiator never had the drain plug replaced with a petcock. All radiators should have a drain hole........look for it. Worst case you could remove bottom radiator hose from radiator or WP side to drain, but I think you will find a drain plug if you search.

Larry

[Joe L.]

Re: 67-L71 big block coolant change

Hello to all; I have no idea how long the coolant has been inside my 67-L71. Car was restored in 2010. Want to change out with Zerex 50/50 mix. Is this coolant appropriate? Also, I have never changed coolant on a big block....and I don't see a drain cock at bottom of the radiator.... as per my previous small block cars. Can anyone please run me through the process?
Thanks in advance.

David------


Your cooling system has a factory spec of 23 quart capacity. The radiator should have either a drain plug or a drain cock. All original Corvette radiators had one or the other, usually on the right side tank.

[Stephen L.]

Re: 67-L71 big block coolant change

Drain petcock location on a 67 BB L36

[Enzo C.]

Re: 67-L71 big block coolant change

Drain petcock location on a 67 BB L36

Very nicely done .. thanks

[Mark E.]

Re: 67-L71 big block coolant change

Drain petcock location on a 67 BB L36

Maybe this car is different, but I usually find the drain plug/petcock at the bottom of the right radiator tank.

[Richard G.]

Re: 67-L71 big block coolant change

If you drain the block completely, like what happens when you pull the block plugs, don't forget to pull a top heater hose before filling.
If you don't the block will have air in the top and can overheat.
Just fill until you get the level to the heater hose fitting and reinstall. It will be enough to keep the block from air locking.
Rick

[Stephen L.]

Re: 67-L71 big block coolant change

Photos of my ORIGINAL 427/390 BB Radiator...…. drain petcock location..... Lower drivers side diagonally located across from the filler neck on the top right. (Possibly different than a small block radiator???? I don't know...…. small blocks and L71 do not have an integrated tank...….)

[Joe L.]

Re: 67-L71 big block coolant change

Photos of my ORIGINAL 427/390 BB Radiator...…. drain petcock location..... Lower drivers side diagonally located across from the filler neck on the top right. (Possibly different than a small block radiator???? I don't know...…. small blocks and L71 do not have an integrated tank...….)

Stephen-------


1967 small blocks use an aluminum radiator with no integral tanks. The tank was external. Draincock was on driver side.

The 1967 L-71 was equipped with the same radiator as L-36. It had integral tanks on both sides and a filler on the right side tank.