Engine zincs

[pschauss]

I know where the zincs on my heat exchangers are. Are there any others on the engines, transmissions, or other components that need to be replaced? (Mercruiser 454s)

[Donmystic1]

There may be zincs in the tranny oil cooler and the engine oil cooler

[Stephan]

There may be zincs in the tranny oil cooler and the engine oil cooler

My Crusader 454s have a single pencil zinc in the bottom of the "U cooler" at the front of the engine.

[pschauss]

Is that the same as the heat exchanger on a mercruiser?

[Charlie J]

on my 230 yanmar
i have 5 or 6 on each engine

[Stephan]

Is that the same as the heat exchanger on a mercruiser?

Appologies for the delay in response and for the picture size below.
The Oil cooler I am referring to is in the red box in the picture below. The orange arrow points to the location of the pencil zinc. My oil cooler Zinc is an E-0 from http://www.boatzincs.com (The heat exchanger takes an E-1 zinc). Please note the engine pictured below is raw water cooled and does not have a heat exchanger - it was just the best picture I could find of the oil cooler.

[pschauss]

Are there any zincs on the sea strainer?

[Tony Meola]

Peter

No zinc on the strainer. My old Merc 454 only had them on ther heat exchanger

[THESALTYSATO]

I purchased a a 31 Bert 2 years ago. The boat has Yanmar 6lp 315 hp with Hurth ZF transmissions- model # NSW 630A 1 with 2:1 ratio. I have had the engines and transmissions serviced 2 times but I do not ever remember seeing a charge for zincs or filters being replaced on the transmissions only changing of the fluid. I have looked on the internet for an owners manual but can not find one only a shop manual. Does anyone know it there are in fact filters and zincs on the transmissions and if so where and the part number and also what is the best transmission fluid to use . Just another rookie boat owner trying to learn his boat.
Thanks

[Amberjack]

SaltySato--You have the same equipment I have on Amberjack right down to the 2:1 gears. Its a sweet package and if you take care of it it will take care of you. There is a transmission filter. Look for a 2 1/2" cap opposite the dip stick. I change mine every 3 years and its easy. Use automatic transmission fluid, I might remember it's called Mercon II. Next time I'm in my records I'll look for the name.

Since you're new to the engines, here are the other Yanmar 6LP maintenance items to stay on top of:
change all six engine zincs annually. Some of them go surprisingly quickly.
replace the raw water impellers every two years. Its a common impeller you can buy them at any marine store for 1/3 what Yanmar charges for the same part. Have the mechanic do it, its a miserable job.
it's critical to change the coolant regularly. Yanmar says every year and that's not a bad idea. I change mine every other year on a light year and every year on a heavy use year. Use the Yanmar coolant, I haven't found an exact duplicate and its important for preventing internal corrosion.
keep an eye on the raw water heat exchanger and the lube oil heat exchanger. My R/W heat exchanger lost efficiency and had to professionally cleaned out after about 5 years.

[Yannis]

I dont have the 6lp’s, I have the 4lha’s 240.
One thing you quickly learn with Yanmar is you always change the 6 zincs with original Yanmar replacements every year, and you change/add only the original Yanmar radiator fluid whenever it’s needed for each motor type, or else you rust your engine.
For the rest I cannot comment because we have different motors.

[THESALTYSATO]

Amberjack and Yannis
Thanks so much for the reply and the information. I checked with the service department who did the last servicing in May 2018. They only billed me for four zincs on each engine not six. They do not know why only charged for four not six. I am guessing the reason I have only four is because they installed last year Kims Hotstart engine block heaters and they used the zinc holes for the heater. I do not know but I am going to meet with the mechanic in a few weeks to review this. I do not know if this is correct but I am going to find out. Also they changed the fluid in the transmission with auto fluid but did not change the filter. Again I need to know why no filter. The coolant was changed with Yanmar antifreeze. Also I was told and charged that the heat exchanger was cleaned 2 years ago when the engines were out of the boat(by a different boat yard) when I had to replace the stringers. At that time I had them install an L- bracket piece of aluminum to run the length of the stringer for the engines to displace the weight of the engines as well as all new engine mounts as 2 were broken. Again thanks for the information and your insight . Hopefully I do not have any metal loss. One thing I think to my advantage is that the boat is on a lift and not in the water so hopefully less electrolysis. Have a wonderful spring and enjoy the best boat on the water. I have thoroughly enjoyed mine in the short time I have been the caretaker.
john

[Yannis]

About the Yanmar coolant:

When I bought my boat I found out that the coolant used by the previous owner was not the original Yanmar coolant. It was pink, but was not Yanmar.
This had as a result the coolant color in the motors having been changed to almost dark brown/black, denoting rust creation and limited protection. During the following service I changed the coolant completely and continued to change it every year until, 2 years ago, for the first time, it came out pink as the color of the new unused Yanmar coolant is. This coolant is expensive so there is no point changing it every year, or changing it as a precautionary measure. Also, I’m not aware of a Yanmar suggestion to change the coolant every year or two, at least in the 4 LHA’s.

What I also noticed is that if you can use a 20 or so liter canister for the used coolant (as you take it out of the motors) that is transparent enough so you can tell the used coolant color, then, if you let it sit for a few minutes you will see the lower part being darker, as the rust impurities are heavier. You can reuse the upper clean part and save money, by pumping out only the top portion of the canister. Transparent canisters I found from swimming pool chemicals.

Good luck, it is true that during the first few years of owning a boat there is a lot of stuff to learn and a lot to do...

[THESALTYSATO]

Yannis
Thanks for the idea. This season when I change the antifreeze I am going to put the old in a container as you suggest and let it sit. This will let me know if I am having any corrosion or rust issues with these engines. Again thanks for the follow up and your insight. Hope you have a safe and healthy boating year.
john

[Yannis]

John,

You can see corrosion or the color of the coolant in the expansion tanks. If they’re dirty and cannot see through, just open them and look inside.

I took mine off to clean, I put chemicals, I shoved them in the dishwasher...nothing, they remained almost as dirty/stained from this rust as before. Perhaps there’s a solution to soak them in but I’m unaware of it.

[THESALTYSATO]

Thanks again Yannis for your comments. I am leaning something new everyday. For two years I have constantly reviewed the website for ideas and solutions others have been through. By seeing what others have experienced is a great teacher. It also saves down time and expense in the future and gives you a better understanding of your boat. What a great forum (gam). Have a blessed day.
john

[Amberjack]

John--Yanmar issued a service bulletin several years ago that was very emphatic about 6LP-STP (315 hp) engines. You can find it on the Mack Boring website if you Google Yanmar 6LP-STP coolant. Because of the dissimilar metals used in the cooling system you will experience galvanic corrosion unless the correct coolant is used. Yanmar says for 6LP models to change the coolant every 250 hours or 1 year vs 500 hours/2 years for all other models. I remember seeing a service bulletin that said not to rely on the color of the coolant or contrary advice from independent mechanics but to follow the updated service recommendations, so I do.

Originally engine zincs, now engine coolant. Another thread that's wandered off topic but has generated a lot of interest.

[Yannis]

Amberjack,

Interesting...

Now as we understand, for those like me who do 40 hours a year, would this prolong the interval between coolant changes?
Forty hours X min 22nm / h = 900/1000 n. miles... an engine that does not work as much compared to one that works 5 or 10 times more, do they incur the same galvanic corrosion?
I also knew about the metals in the 6lp’s..is this also true for the 4lha’s?

Also, the Japs are right, they should expect the majority of the mechanics to object to these frequent changes.

[Tony Meola]

Yannis

If you are looking to remove rust stains from those plastic bottles there are two products here in the US that I would try. I have had luck using them to clean up rust stains and Calcium deposits.

One I find in the local cleaning section of the Supper Market it is called CLR ( Calcium Lime Remover) the other is called "Iron Out" and I usually find that in Hardware Stores. Used to be sold in Home Depot but I have not seen Iron Out there in a while.

https://summitbrands.com/product-category/iron-out/

[Yannis]

Thanks Tony,

I think I know the equivalent product, next time I flush the coolant I’ll give it a try.

[Amberjack]

Yannis--The service bulletin I saw only mentioned the 6LP models. I don't know if 4LS models are built differently or if perhaps they are addressed in a separate service bulletin. Try doing an online search for Yanmar 4LS coolant to see what turns up. When I have the engines serviced this year I'll try to remember to ask the mechanic.

As a side note they do a lot of service on the 6LP's as that model popular with Alaska Bristol Bay gillnetters which turned out to be a disaster for Yanmar. The fishermen would fire up the boats in the fall, run them at either idle or WOT, nothing in between, for 4 weeks, dump them at the packing plant for the winter, then repeat the process next fall with maybe an oil change. The warranty claims were horrendous and I have seen them in the shop covered with rust but still somehow running. Yanmar since rewrote the manual to specify "for pleasure use only"

I wrestle with that question of coolant change after low hour use also. Some years I ran for only 50 hours and was tempted to put off the coolant change for a year. Now I think my solution is to run the boat more hours during the season so I don't have to fret the decision!

[Yannis]

Doug,

Thank you, I more or less expected to hear most of what you wrote! Except for the fishermen story of course, which leaves me with a feeling that Yanmar chickened out somehow with this “only for pleasure” statement, as if they were talking about...dildoes.

I did a quick search about coolant flushing yesterday, after your previous post, specifically on the 4lha’s, but didn’t find anything. Apart from some suggestions on how and when to change the raw water side (the rinsing procedure), there was nothing on the coolant side. Nothing. I’m not a computer wizzard, nor did I read all 70 or so pages of the manual, but I didn’t become any smarter...also, I couldn’t find any specific service bulletin on the issue.

One would expect that the all meticulous Japs would have already made that modification in the manual stand-out like a yellow flashing star on a toothpaste packaging, so as to convey the importance of the problem. Even in the 4lha’s where, as you claim, the coolant flushing should take place every two years and which, in my view, is already too frequent. Nor is Mc Boring the official Yanmar service authority worldwide so that every owner should reach out to for potential service bulletins...unless they are!

It would be interesting if someone with real experience on the specific issue could give us a definitive answer.

Enjoy your boat!