Engine Zinc (HX)

[HydroTherapy]

Hello:

I changed the zinc on my boat today.  When I unscrewed the old zinc there was only a little tip left.  There was zinc still inside that had to be pushed up and inside so the new zinc would be able to be installed.

Did I do anything wrong?

Thanks for the feedback.

David

[Gene Regan]

David,
At this point your best bet is to remove the heat exchanger. This will give you a chance to clean it out and take it to a radiator shop to have it boiled and roded out. There has been much discussion on this topic on the board.
By doing this you will get any old pieces out and also do your cooling system a big favor. You may even see a difference in your engine cooling temp. Its a win win. When doing this also be sure to replace your end cap gaskets and maybe also order two new end caps. They can be be purchased from Torrenson marine.
The process is easy and does not take much time at all. Good luck and keep smiling.

[Mike Vaccaro]

David,

The old pencil zinc has just broken off.  This is fairly typical and won't cause any problems.  As a rule of thumb, if you are running a 160 degree thermostat, you should remove and clean the exchanger when your coolant operating temperature consistently runs 10-15 degrees warmer (e.g., 170-175 degrees in this case).  Before you remove the exchanger, ensure that you've got new rubber gaskets for the end caps.  If you do a search of this site, you'll also find a replacement "heavy duty" end cap that may be less prone to weeping than the stock design (which we've found to be adequate when properly torqued with a good gasket).  The only "weak" point in the design of the heat exchanger on the M-25 series engines are the hose clamps that hold it in place.  They are prone to vibration cracking and merit regular inspection.  I recommend that you always care at least one spare aboard for this purpose.  

Best of luck,

Mike

[DEMERY]

David,

I've had the same problem with the zinc dissolving / breaking into pieces when I've waited to long between changes. What has worked well for me is to remove the end cap nearest the zinc and then use a shop vac to vacuum out the pieces.

Good Luck,

Dave

[Stu Jackson]

Easy Solution to HX Zincs:

We change ours every quarter.  I remember to do this whenever the newest issue of Mainsheet magazine arrives at our doorstep.  

I've found that if I replace it every three months, not too much has worn off, so I don't have to go fishing for itsy bitsy zinc parts inside the HX.

If you replace the zincs BEFORE they get all rotten, it's a lot easier task.

[Ron Hill]

David : Before you remove the entire heat Xchgr why not try this:

Remove the port side end cap and with a mirror - look inside.  You'll probably see some junk that you can get out with a piece of angled coat hanger.  If your engine is running at 160 degrees you don't need to "boil" it out.
Most important when you add a new zinc is to measure the distance/length for the new zinc.  Done easily with a #2 pencil and transfer that distance to the zinc and then hacksaw it off to match.  When in doubt on the length make it  shorter!!

Call Glenn-Marr marine (800)282-0123 and order new gaskets or an or a complete end cap/gasket kit.  Just tell them which size heat xchgr size you have.  

[captran]

I have used the mirror trick which I like, but to clean it out I have used a shish-ka-bob skewer, gently making sure that all the tubes are clear.  I also "flush" it as I am cleaning it, starting at the top and end at the bottom.  I use an old squeeze syrup bottle filled with water, holding it right up to the tubes and forcing water into the exchanger.  It's amazing how much sediment came out.

[HydroTherapy]

Thank you all for the good advice.

David