A Question on 6LP-STE Zincs?

[Chris & Dale]

Amongst all the other items being done by Mack Boring during our 1200 hour timing belt change is the replacement of the 6LP-STE 300 hp engine zincs. It's a 1997 engine in a 1999 Albin 28 TE. It's a little complicated the way it evolved, so please be patient.
1. The mechanic's assistant removed the plug on the transmission cooler and thinks he removed the remnants of a zinc, which may have been nothing more than crustation. When he tried to put the new zinc in it wouldn't fit. So they put the brass plug in empty to deal with another day. The assistant must have thought this was the 5th zinc.

2. In reviewing the Yanmar manual I discovered the 2nd zinc location on the fresh water cooler, investigated with a mirror and found it, and it had not been changed. In fact, it was painted grey like the rest of the cooler.

3. The previous owner turned over to me meticulous records and in reviewing those about previous zinc replacements I found they only replaced 4 each year instead of 5. I contacted that MB dealer's mechanic and he told me the lower zinc on the fresh water cooler end plate was a bear to get to and really wasn't necessary, so they hadn't done it for years. There was no record of ever replacing a zinc in the transmission cooler.

So, having described all that, here are my 2 questions:

1. Has anyone forgone the replacment of the lower zinc on the freshwater cooler, and has there been any consequences?
2. In this vintage Yanmar w/a Velvet drive, does anyone have a transmission cooler that does have a zinc on the port side of the boat, or is this just a plug that's been mis-identified?

Please share your experiences and advise. Thanks in advance for your repsonses.

[RobS]

Was there any zinc left on it? The fuel cooler can be inspected by removing the top seawater hose and looking down inside. If the cooler is original you should consider replacing it. Mine sprung an external leak that I detected right after a rydlyme flush. It leaked seawater out from a joint at one of the welded nipples. No biggie. BUT, a guy I know, also with a 2000 boat, had his fuel cooler fail internally between the fuel passage and seawater passage resulting in the raw water pump pushing seawater into the fuel tank. He realized it when the engine quit.

As far as the tranny cooler, is the plug you are referring to the same thread as a zinc cap? When you say it would not fit, due to the threads or the length of the pencil zinc?