Originally Posted by Saltyhog
How difficult is it to remove the entire heat exchanger from the engine? It looks to me that there are just 4 hoses and 2 bolts, and the whole thing comes off. I wasn't very clear in my original post. I plan to remove the heat exchanger, and then clean out the old zinc pieces and then clear out the tubes. I've seen recommendations to run a wire/welding rod through the tubes to clean the crud and scale. I can't replace the zinc because the hole is blocked inside the exchanger with the old zinc. I'm still puzzled as to how to drain the coolant from the block.
This is how I do it on my 44B Four.
I remove the HX & stat then flush with fresh water
. I then do a round of Rydlyme and follow that with another round of distilled water
. I then let that drain off a bit put her back together and add AF until the desired mix is attained. The last step is to replace the stat and gasket
My engine shipped with Dex Cool AKA Death Cool and was badly gummed up. The only way to correct this was a full flush and Rydlyme clean. The HX was boiled/cleaned sand blasted, painted and re-installed.
The two hoses go to an in/out bucket. I use a cheap
Harbor Freight stainless 12V pump and place a valve on the return end of the set up throttled down to keep enough pressure to fill all the cavities in the engine.
My experience with block drains on engines in salt water
use is that you simply stay away from them, especially if hard to access..... BTDT....
I have not found a better way to do a proper flushing
on these engines...