Cummins 6BTA 5.9 HE pencil zinc

[John Larson]

Ive been doing maintenance on our Halvorsen GC32 and found that the pencil zinc in the heat exchanger has broken off at the top of the brass plug. It appears that the zinc is still in the hole. See attached picture.
Can I drain just enough coolant to lower the level in the exchanger so I can remove the end cap and fish it out? Then I wouldn’t need to replace all 21 qts.
If so, approximately how much coolant would have to drained to lower it to that level?
When we bought the boat 2 years ago, the coolant had just been changed and we’ve put about 200 hours on since we’ve owned it.

Picture of engine info is also attached.

Thanks much.

Topic

[John Larson]

Great info. Thanks much!

John

[Rob Schepis]

You should be fine, you have very slight flex in that coolant hose and you also have the option of loosening the 4 strap mount bolts that hold the heat exchanger to the ex manifold to get a tad of movement with the heat exchanger for clearance there too. The end cap bolt is short.

[John Larson]

Here’s the one in question. (Picture isn’t my engine)

[John Larson]

Thanks Rob. My related issue is the the close proximity of the short vertical coolant hose that’s adjacent to the end cap screw head. Is the screw short enough to loosen the cap without running into the hose?

Thanks again.

[Rob Schepis]

Zincs are in the seawater circuit, not the coolant loop. No coolant will be lost, just the raw water, so do contain it as best possible.

See these topics regarding the end caps and regarding pencil zincs:

https://www.sbmar.com/community/topic/heat-exchanger-flat-end-cap-fix/

https://www.sbmar.com/community/topic/pencil-zinc-install/

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