C2 heater hose sealant?

[Randy Swartout]

I am replacing the heater hoses on my 66 small block and will use the OEM type spring clamps. My concern is leakage. Is there a sealer ( not adhesive) that can be used to prevent leaks?
Also according to my AIM manual C60 D3 a screw type hose clamp at the water pump connection is used. Correct?

[Lawrence C.]

Re: C2 heater hose sealant?

Randy-

I have a '66 L79, non-AC small block and I have never had any problem with the heater hoses leaking with the spring clamps installed. This was true when I originally replaced the hoses, and when they have been off a few times for other work. Only time I could see that happening was if a fitting (like perhaps a heater core tube) was out-of-round or had a dent somewhere in it's circumference. If the fittings are round and the hoses are installed correctly I don't think you would have a problem with leaks.

On an L79 anyway, there are spring clamps on all heater hose connections: at the heater core, expansion tank, intake manifold, and water pump. There is a screw clamp where the by-pass hose connects to the water pump and intake manifold, at the top of the water pump.

[Joe C.]

Re: C2 heater hose sealant?

Randy:

I have always used Permatex sealant on coolant hose connections with good results.

Joe

[Duke W.]

Re: C2 heater hose sealant?

The problem with heater hoses is getting them off, and many have cracked a heater core nipple solder joint trying to twist and bend them off.

I now use a very thin film of silicone dielectric grease on the inside of hoses, and I emphasize VERY THIN. This allows the hose to easily come off, but if it shows much resistance, I slice it along the length. If you use and kind of sealer you better slice them if they have to be removed down the road.

GM used the spring clamps because they were quick to install and rarely leak as long as the nipple is still round.

Duke

[Randy Swartout]

Re: C2 heater hose sealant?

Larry, Joe and Duke...Thanks for your input. Randy

[John H.]

Re: C2 heater hose sealant?

The spring-type clamps are still used today on many cars with high-temperature/pressure cooling systems, although they're flat instead of the round Corbin variety; the rationale for using spring-type clamps instead of the screw-type clamps (aside from cost and ease of assembly) is that they exert a relatively constant pressure over the life of the hose, even as the hose material gradually compresses with age under the clamp, and the flat clamps have a squeeze-limiting ear feature that prevents over-compression at assembly. These days, assembly plants use "rose water" (50-50 mix of alcohol and water) as the assembly lubricant for clamped heater and radiator hoses; it has no permanent sealing properties, just makes them easier to assemble.