[ardoski14]

Trying to check everything I can my new to me 88 3300. After installing a rebuilt alternator, I went to change the zincs on the engines. The first three came out fine and was able to but the new ones installed. When I went to remove the port engine oil cooler zinc the zinc part stayed in the cooler. Is my question the only way to get it out is to remove the oil cooler? Attached are the photos of the ones I removed. Thoughts on bad? Have they been in way too long?

[reeltimebrad]

Well cant seem to open your pics, so not really sure what you mean by oil cooler zincs as the only thing i've seen on oil coolers are water drain plugs and they didnt have a zinc attached like the ones in the coolant heat exchanger.

[czarcone]

I'm assuming you are referring to the U-coolers on the front of each engine.  I would try to use a pick & remove any remains of the old zinc, but, as the coolers are pretty much closed vessels, I'd probably leave them behind to eventually be eroded away by the raw water flow.  To some degree, whatever is left in there may hinder the insertion of the new zinc & have some effect on future flow until it breaks down further.
The zincs in your pics show them largely intact, but the extensive erosion at the base will only cause you to have the same problem again.  That being said, I change mine every season.  Very inexpensive & easy to replace.  As you may already know, the zinc can be unscrewed from the brass cap & a new one installed, lowering the cost even more.
Hope this helps

[ardoski14]

I'm assuming you are referring to the U-coolers on the front of each engine.  I would try to use a pick & remove any remains of the old zinc, but, as the coolers are pretty much closed vessels, I'd probably leave them behind to eventually be eroded away by the raw water flow.  To some degree, whatever is left in there may hinder the insertion of the new zinc & have some effect on future flow until it breaks down further.
The zincs in your pics show them largely intact, but the extensive erosion at the base will only cause you to have the same problem again.  That being said, I change mine every season.  Very inexpensive & easy to replace.  As you may already know, the zinc can be unscrewed from the brass cap & a new one installed, lowering the cost even more.
Hope this helps

That was my concern of just leaving it in there. So I think I'm going to remove the cooler and remove the old zinc. If there was room I think I could pull it out, but location doesn't allow that. The picture attached is the starboard cooler which removed with no problems.  Thanks

[RMS]

To remove the stuck zinc, cooler removal is probably necessary. I would not rush into that however. What I would do (and have in the past) is insert the new pencil zinc and take the boat for a ride. If the engine is not running excessively hot, leave it be.

I notice your home port is fresh water. In salt water (my home port) I would replace the pencil zincs twice a year to prevent the anodes from breaking off. Going forward, check the anodes every few months and replace as you wish.

Bob

[ardoski14]

To remove the stuck zinc, cooler removal is probably necessary.  I would not rush into that however.  What I would do (and have in the past) is insert the new pencil zinc and take the boat for a ride.  If the engine is not running excessively hot, leave it be.  

I notice your home port is fresh water.  In salt water (my home port) I would replace the pencil zincs twice a year to prevent the anodes from breaking off.  Going forward, check the anodes every few months and replace as you wish.  

Bob

The old one is still in the hole to point barely any water drained out of the hole. Think I'm just going to pull the oil cooler off tomorrow and get it out. I definitely will be part of my seasonal maintenance plan.

[Tgilbert]

Do you use the same pencil zinc in fresh water as you do in salt water?

Thanks,
Tom

[reeltimebrad]

Should be using magnesium not zinc for freshwater. zinc is almost inert in freshwater.

[ardoski14]

I replaced all mine with Magnesium.

[jclark003]

As an option you could try a product such as barnacle buster. It will probably dissolve what is left of the old zinc and clean out your heat exchangers. Just make sure to remove your new zincs / magnesiums before flushing and reinstall afterwards.