Radiator drain plug

[Gary B.]

Re: Radiator drain plug

Is there a recommended coating to apply to the threads of the petcock or drain plug to prevent galling or facilitate loosening in the future if need be?

Gary

[Terry M.]

Re: Radiator drain plug

Is there a recommended coating to apply to the threads of the petcock or drain plug to prevent galling or facilitate loosening in the future if need be?

Gary

I had the same experience as Richard K. Remove the lower hose from the radiator and all the coolant comes out. Try not to have to cut the lower hose. The lower hose is almost as hard to replace as the radiator on C3s. There are tools that have a right-angle pick to work between the hose and radiator fitting to losen the grip of the hose on the radiator, but being too aggressive will still Buba the connection. Think smarter before you act. I love a small amount of silicone grease on the inside of the hose to radiator connection, but I know all about how bad that is. The key is to use a small amount and tighten the hose clamp well. If I had a car with spring type hose clamps, I would rethink that action.

Gary, I don't think there is anything one can put on the plug threads to facilitate the removal without twisting the right-angle fitting. Give up and remove the lower hose.

Be glad some of us don't have the aluminum/plastic radiators (you C4 & C5 guys have my sympathy). The plastic drain plug with the O-ring seal is no better. A new O-ring and silicone grease help. but the lower hose is still the go-to for me on those radiators also.

[Joe L.]

Re: Radiator drain plug

I had the same experience as Richard K. Remove the lower hose from the radiator and all the coolant comes out. Try not to have to cut the lower hose. The lower hose is almost as hard to replace as the radiator on C3s. There are tools that have a right-angle pick to work between the hose and radiator fitting to losen the grip of the hose on the radiator, but being too aggressive will still Buba the connection. Think smarter before you act. I love a small amount of silicone grease on the inside of the hose to radiator connection, but I know all about how bad that is. The key is to use a small amount and tighten the hose clamp well. If I had a car with spring type hose clamps, I would rethink that action.

Gary, I don't think there is anything one can put on the plug threads to facilitate the removal without twisting the right-angle fitting. Give up and remove the lower hose.

Be glad some of us don't have the aluminum/plastic radiators (you C4 & C5 guys have my sympathy). The plastic drain plug with the O-ring seal is no better. A new O-ring and silicone grease help. but the lower hose is still the go-to for me on those radiators also.

Terry------


Spring clamps are actually superior to screw clamps. Spring clamps of the proper size exert a constant clamping force of the rubber hose even as the hose progressively compresses over time. Screw type clamps do not. They have to be periodically tightened to compensate for hose compression. Very often this chore is forgotten. Then, at an inopportune time the hose can separate from the radiator.

[Terry M.]

Re: Radiator drain plug

Terry------


Spring clamps are actually superior to screw clamps. Spring clamps of the proper size exert a constant clamping force of the rubber hose even as the hose progressively compresses over time. Screw type clamps do not. They have to be periodically tightened to compensate for hose compression. Very often this chore is forgotten. Then, at an inopportune time the hose can separate from the radiator.

Joe
My direct experience with spring clamps is limited to, my long-forgotten youth. I can tell you that I am among those who don't periodically tighten screw clamps and only once have I had a screw clamp fail. That was shortly after installing it and I suspect I failed to tighten it sufficiently during that installation. I did have another radiator hose failure, but that involved a fabricated installation that didn't have the raised bump on the metal tube. Installing that protrusion solved that failure. My conclusion was that was not a failure of the screw clamp, but rather a failure to fabricate a proper connection.

I should add that I will often place some small amount of my favorite lubricant (silicone grease) on the interior of the screw clamp. This allows for less friction between the metal of the clamp and the rubber of the hose. It allows the screw clamp to "creep" around the rubber hose and apply mor even pressure to the hose.

I really like the screw clamps that are entirely stainless steel, screw and all. The inexpensive OEM screw clamps with steel screws are prone to corrosion in daily use and proper clamping force is problematic with repeated use. They work OK for initial one-time use but should be upgraded for frequent regular use unless judging is a concern.

If you wish to preserve your radiator hoses, there is a special type of screw clamp that has a smooth surface all around the contact surface with the hose. The usual openings in the band for the screw are either raised for the screw to get purchase or the smooth band wraps all around the surface that is in contact with the hose. These in stainless steel are usually available from marine supply stores. They are used on silicone radiator hoses in marine applications and on police service vehicles. In police service these clamps and hoses are life-time items and never need changing. I can't speak to the marine application, but I expect someone who does will read this and enlighten us.

This is all probably more than you wanted to know about screw clamps. Don't get me started about tower clamps. Those are a whole other story.

Edit add: Upon review of this post, I realize it is entirely off-topic. I apologize to the OP. I have spent the time to post it, but realize I should perhaps start a new thread on the subject. I will do so but leave this here as a response to Joe L. because my personal experience runs counter to his advice, but my install methods may be different that the norm.