4BY engine zinc anodes

[JerryE]

Since I had heater hose leaks, I am having the factory recall done to replace the heater hoses on the 4BY 150 hp engine in my 2009 R25. I asked that the mechanic change out my engine anodes of which there are three. However, if you don't have the optional high-rise elbow (3) on the picture below, you don't have that zinc which is the case on the R25 models. All engines in this series have anodes in the heat exchanger (2) and charge air cooler (3) in the photo below; click on the photo to make it bigger. Of interest is the fact that the lower (1) anode for the charge air cooler was only a cap, no anode was installed there on my boat.

Does anyone know if there should be an anode in that spot? My mechanic is calling our local Yanmar distributor for his opinion. Maybe it just wasn't installed when the engine was commissioned by my dealer or the factory?

 

[baz]

Today I changed out my 2 engine zincs on my 2010 R25 150 HP Yanmar engine. I meant to do this last year and have only just got around to doing it. I must say I should have done this earlier as from the photo included here you can see the old and new side by side. The one without any zinc anode (left one and completely eaten away) is the old one. 😉

To answer your question about the lower mounted zinc anode... on mine the old one clearly had an anode as it was completely eaten away.

I also noted that the lower anode bolt had a water whereas the upper one did not have one. Weird that...

The nut size for the two anode bolts is 15/16" and I used an adjustable wrench with a short handle. The original ones turned without too much effort.

When the top one was removed little to no coolant seep out. However, when releasing the lower one I had to quickly insert the new anode as coolant flowed out. I'm guessing I lost no more than 1/2 cup of coolant. Of course one must ensure the seacock is closed as well.

 

[walldog]

Maybe I am a little dense, I have called worse, but why would the zinc be in the coolant system? Sea water yes, but why would there be coolant coming out when you remove the zinc?

 

[baz]

Yea -- it must have been sea water. 😉

 

[walldog]

Yea -- it must have been sea water. 😉

At least you do not have to replace that cup of seawater....grins

 

[Namaste]

Changing my engines zinc on my 2010 R 25 4BY2 - 150 is giving me more than I can handle.

First off, I had a hard time distinguishing them from all the other bolts heads in the engine. I was assured by the dealer the engine zincs had been changed when I bought the boat used last year but the zinc bolt heads were still spray painted the engine grey / silver. The replacements I got direct from Ranger were brass.

I find these heads to be 23mm. The replacements are 7/8. My 15/16 socket is way to loose to get any torque on the old ones and 7/8 will not fit. I was finally able to get the upper one off and replaced using a vise-grip on it. The lower one has yet to budge. I have it sitting in penetrating oil while I await delivery of a 23mm socket. I am not certain that will work when it arrives. Think about three dissimilar metals sitting in seawater for three years . . . Has anyone drilled these out? Taken a blowtorch to them? Other?

 

[baz]

Yes -- the lower one is a PITA to get at and turn loose. There's very little room for leverage and I use a wrench that is cut in half because the complete one is just too long and butts up against the engine starboard bulkhead.

It is possible to use an articulated socket to grip the lower anode bolt nut, but that is also a PITA.

Persevere is my advice and watch your back as you lean into the engine bay.

The lower anode sits in water and erodes far quicker than the upper one as that one sits in air while engine at rest.

Good luck... 🙂

 

[sleepyboat]

Regarding the question by Namaste; the anodes can be unscrewed and replaced using the same bolt head and washer (gray). You can also be an overachiever and replace the complete assembly new, which would be unpainted brass. I have new bolts and spare anodes and rebuild the bolts I remove and keep as spares. Maybe the anodes were replaced without a new bolt? And yes the lower anode is a PITA to get a wrench on and gives you little leverage and not much throw and just when I was ready to give up on the lower painted bolt it finally gave way. Regarding the drilling out option, I had difficulty getting a wrench on the lower bolt and think that a drill is not an option and “blowtorch”? NO NO NO! A safer option may be using extreme cold (canned Freon or some like gas) to shrink the bolt slightly and break the bond. I have seen this done with water pumps and heat exchangers. BTW, being just north of you, with two seasons past, they needed replacing every 8 weeks +-. I went longer 12+ the first year and ended up with nubs on the end of the bolt.
Regards,
JD

 

[Namaste]

Aye, you can reuse the bolt heads that are painted grey but I bet one would be hard pressed to get them off without damaging the paint. Mine were pristine grey so I shall continue with my belief that they were never changed by the previous owner or by the dealer who assured my the boat had its 50 hour maintenance done and all anodes were changed at that time.

I was finally successful after several attempts to get the lower anode out of the engine. It required a 23mm socket on the indexable ratchet pictured below. The 23mm socket fit perfect and a 7/8 socket fit right on the replacement bolt head on the anode I got from Ranger. The wrench came from Harbor Freight Tools which is not might first choice for a tool source but Sears and the local auto parts places came up with nothing that would work. This set-up gave me good purchase on the lower anode and the bolt came out right away.

Keep in mind this was on a 2010 Yanmar 4by2-150

Link to ratchet = http://www.harborfreight.com/1-2-half-inch-ratchet-with-indexable-head-96090.html

 

[baz]

Jim: nice ref on the ratchet.... Thanks for that. Glad you were able to get that lower engine anode loose.

 

[knotflying]

i am surprised that people are having trouble with this particular zinc. I have been able to break it loose and tighten it with a snug fit from a vice grip. Yes, I can see your faces of horror now 😱 that I use a vice grip. I am very careful to get to on the appropriate faces of the bolt and cause no damage to it.

 

[baz]

I'm all for making things like this lower engine anode removal issue an easier task and the ref for that ratchet seems a good approach at making things easier, especially for folks with hurting backs and/or knees etc. I did try a vice grip at one point but gave up as it was too easy for it to slip. I'm glad you are able to remove it with your technique though... good luck to you. 🙂

 

[knotflying]

It seems that perhaps this is more of an issue on the 25 and not the 27.

 

[baz]

Ah... didn't note you have the R27.... sorry about that. Is your R27 new enough to have the Volvo 200HP engine... and if so, it has no anodes to worry about. 😉

 

[knotflying]

No, it is a Yanmar. I have no problem getting in there so perhaps the configuration is slightly different on the R-25.