"Ted:
Al's method works
"Ted:
Al's method works when things are really clogged. I've found the bulk of my experience has been with the zinc pencils 'flaking off'. I've got a method but it makes things wet in the engine room.
What I've found is backflushing the cooler is the quickest method to purge the crud. If the crud has been sitting a while, Al's disassemble method is required. I keep the pump connected, remove the zinc, and remove the 'outlet' hose from the cooler. I then hook up my 'backflusher'. This is nothing more than an old 3/4" dock hose with the female garden hose thread end still attached, about 5' long. At then other end is a few nylon adapters to 'enlarge' things to 1.25" (hose barb end). over the barb is a piece of straight hose~6" long. Put this to the oil cooler's outlet and hook the other end to the dock water supply.
Get a helper/mate to turn on and off the water. At the zinc's pipe threaded hole, take a beer flat (or other cardbord piece) and bend it out to work like a deflector. Turn the water on and keep watching the water come out. The stream usually changes as the crud obstructs the hole. I usually use an ice pick to knock it out. I've also use a length of #14 stranded copper wire with a little J hook bend into one end to catch the flakes and help in extracting them.
Once done a few cycles, most of the crud will be gone, If the stream exiting the cooler stays constant for a minute or so, you'll probably have the bulk of it flushed out.
For what it is worth, I'd say all of my warm running spells have been due to my negligence in following the recommended maintenance interval. In reviewing my logs books, when changed "by the book", we went as long as 4 years w/o having to backflush the coolers. All the issues were coupled to ambiguous entries in the log book - read that as if you don't change those pencils, you'll have much more work (and expense) ahead of you.
The other item that helps is going to the local supply store and buy a 5' length of clear PVC hose with 1.25" ID. You can install this is most locations (TEMPORARILY ONLY) thruout the cooling system to assess the flow. I'd suggest getting a baseline by installing the inspection hose on the cooler when clean. (other engine in a twin install can help, too.) Then if the Temp Gauge stays up, get out the hose and see what the flow is like. You can also use this on the fresh water side, if needed, but you'll have to be cautious with the antifreeze. Good flow is solid, clear flow; bad flow is aerated, pulsing, etc. The difference is usually quite obvious.
hope this helps mark"
