Radiator drain plug

[Jeffrey S.]

Hello All,
Which of these two drain plugs would be more likely found on a '69 small block with A/C? The one on the left is what I have on my Oct '68 car but the extension from the shut off flange almost touches the cross member and makes it difficult to drain without making a mess. The shorter one would allow for something to be put under it directing the flow into a container. I plan on using the shorter one no matter what but I want to know if one is more expected than the other.

[Joe L.]

Re: Radiator drain plug

Hello All,
Which of these two drain plugs would be more likely found on a '69 small block with A/C? The one on the left is what I have on my Oct '68 car but the extension from the shut off flange almost touches the cross member and makes it difficult to drain without making a mess. The shorter one would allow for something to be put under it directing the flow into a container. I plan on using the shorter one no matter what but I want to know if one is more expected than the other.

Jeffrey------


The shorter style was used. I've never seen the type on the left used on a Corvette.

By the way, since your radiator is a copper/brass type, the brass petcock was used.

[Jeffrey S.]

Re: Radiator drain plug

Joe,
Thanks for the reply. That is actually good news since it will make draining the rad. much less messy.
Jeff

[Paul O.]

Re: Radiator drain plug

Jeff

No petcock was used from the factory. Here is what was used a brass plug and 90deg elbow.

[Joe L.]

Re: Radiator drain plug

Jeff

No petcock was used from the factory. Here is what was used a brass plug and 90deg elbow.

Paul------


For 1969 I believe a petcock was used. Beginning for 1970 I think this was changed to the elbow and plug (for copper/brass radiators).

[Jeffrey S.]

Re: Radiator drain plug

Joe and Paul,
I just helped a fellow chapter member drain and refill his '70 and this elbow and plug was what was there. I thought it was someone's idea of an improvement (which it really was) but not factory. John will be very happy to find that this probably came from St. Louis this way.
Jeff

[Jeff P.]

Re: Radiator drain plug

Paul, I thought the plug was also used in 68 small blocks with copper radiators for AC.

[Joe L.]

Re: Radiator drain plug

Paul, I thought the plug was also used in 68 small blocks with copper radiators for AC.

Jeff------


I might be mistaken on this. However, I always thought the drain plug began for 1970 for applications with copper/brass radiators. It might actually have begun earlier. If so, my apologies.

[Jeff P.]

Re: Radiator drain plug

You would know better than I Joe. So possibly in 68 ,SB with copper radiator had the bolt with the 90 degree block?

[Paul O.]

Re: Radiator drain plug

Yes 68 and 69 had the same brass elbow and plug.

[Jeff P.]

Re: Radiator drain plug

Thank you Paul.

[Joe L.]

Re: Radiator drain plug

Yes 68 and 69 had the same brass elbow and plug.

Paul-------


If that's the case, then they must have been built contrary to the AIM. I checked my recollection and the 1968-69 AIM's show a petcock with no elbow for copper/brass radiators.

[Joseph W.]

Re: Radiator drain plug

I know this is an old thread, but thought I would update it.
I was doing some research on my 1969 L89 and I have the original Harrison brass/copper radiator.
It has the brass elbow and plug.

[Mark E.]

Re: Radiator drain plug

Yes, an old thread but a comment...

A mechanic friend once coached me to never open or use radiator petcocks. Forcing one open that's seized from crud risks bending and/or cracking the radiator tank.

Instead, drain the radiator by removing the radiator hose.

[Richard K.]

Re: Radiator drain plug

Agree with Mark. Ask me how I know (from many years ago). While turning the plug, the elbow broke loose from the radiator tank. Had to remove the radiator, radiator support, and radiator shroud. Big job. Took the rad to a rad repair shop for refurbishment.
Either remove the lower hose by hand, or cut it off! After that nightmare I had, I'll never touch the drain plug again.