1970 R1600 heater, how to test it for leaks?

[Mspencer]

The PO has bypassed the heater in the engine compartment so i expect it was leaking inside. I have pulled the heater\fan box and will be replacing the short and long hose under the dash and also wanted to see if there is a "Test" to see where the heater may be leaking? I have also removed the Heater Valve and cleaning that up and i expect that it may also be suspect of leaking. Any guidance figuring this out is greating appricated.  

[datzenmike]

Submerge the core in water with hoses on the ends. Thumb over one hose to seal it and blow in the other. Bubbles would be a leak.

 

If you have to remove a really old hose plan on replacing it, (better now than when back in place) slit them lengthwise with carpet knife rather than twisting and pulling on the copper necks. The solder that seals them is rather fragile.

[Mspencer]

2 hours ago, datzenmike said:

Submerge the core in water with hoses on the ends. Thumb over one hose to seal it and blow in the other. Bubbles would be a leak.

 

If you have to remove a really old hose plan on replacing it, (better now than when back in place) slit them lengthwise with carpet knife rather than twisting and pulling on the copper necks. The solder that seals them is rather fragile.

Great, i will test it. Thanks

[MikeRL411]

Ah the good old days!  Replacement heater cores listed for $18 and fit perfectly.  I have one in my RL411 and donated the leaky original to a Roadster owner not too long ago.