78 DeVille Heater Core

[Joel Den Haan]

My 78 DeVille with just over 100K KMS on it (Canadian) has developed a leak in the heating system.  Its not pouring steam out onto the windows, just a light mist accompanied by a periodic old antifreeze smell.  Should I replace the heater core completely, or rather flush it through and then add Bars Leaks?  Its not an expensive part, but if another simpler way is available....

[Michael Stamps 19507]

I vote for replace as I think you will soon find it a lot worse.

Stampie

[Bruce Reynolds # 18992]

Gday Joel,

I am with Stampie.   Using Bars Leak, which however I find is the best Radiator Stop Leak product on the market, will fix the problem foe a short time.

But, if you are experiencing what you describe, which is a failure of either the Heater Core, or the Heater Tap, then when it does go in a big way, which it will, it will make a mess.

Once a leak starts in an Heater Core, then the rest of it will be very suspect as these cores dont take the pounding that a normal Radiator has to endure, and I think they are made out of thinner material, just because of that reason.

I vote to replace it, but get yourself a Workshop Masnual to guide you through it.

Bruce,
The Tassie Devil(le),
60 CDV

[Joel Den Haan]

Replying on 78 DeVille Heater Core-
Thats about what I figured- its actually been doing this for a while, and Ive replaced the hot water valve already.  Thanks for your advice.

[Jeff Traikoff]

Leaking heater cores are just bad news.  When you replace it make sure you clean up the area around where it has leaked, it literally causes a rotten mess.