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Heat exchanger zinc

our38

Member II
Now that our E38 is back in the water, several neighbors at the docks have stopped by and asked if checked or replaced the zinc in the heat exchanger? From their expression and reaction, I guess I must have looked like my german shepherd with my tilted head and confused look when I said 'huh'? So, that said, went looking for this mysterious thing that several folks have now mentioned. Since this is my first experience with owning a sailboat, or diesel engine, I'm not entirely sure what I'm looking for, so if someone could possibly describe where on/in the heat exchanger I might find this zinc, it would be much appreciated. When I do find the zinc, am I going to have to drain the coolant, or whatever is in the heat exchanger, in order to change the zinc, or will I be able to do this without all the mess? Again, thanks in advance for everyone's feedback. By the way, this E38 has a Universal 32, 5432, if that helps.
 

our38

Member II
Thank you sooooo much. The diagram is exactly what I needed; I'll head down to the boat today and see if I can get it out without too much mess. I think it's only been in there for about eleven years; I wonder if there is anything left ?
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
If it hasn't been serviced in a long time you might want to remove the heat exchanger and have it cleaned and serviced--most radiator shops will do that for little money, and they have the acidic solutions to get it cleaned properly. Otherwise you risk that the heat exchanger is getting plugged and your engine may eventually overheat. It's a good thing to do, maybe about every three to five years, so yours sounds like it's way overdue.

Frank
 

Blue Chip

Member III
After 11 years there had NOt be anything left or it''s not doing it's job. Aman to the radiatorr clean out approach. after all ha time it would be a good idea. BTW we put in a new zinc every spring as I rcall.
 

mherrcat

Contributing Partner
That zinc should be checked every two to three months. (There was a manufacturers sticker on mine that stated, "Check zinc monthly.") I am usually good for about three to four months before it is looking about halfway gone. Actually, it doesn't "look" like it is "halfway gone" but the metal itself has deteriorated and become soft; if you grab it with your fingers and twist it the soft part crumbles away and you can see that the remaining hard part of the zinc is only about half of what it originally was. That is when I replace it.

When you remove the zinc the salt water that is in that part of the heat exchanger will spill out, but it is only about a cup of water or less.

When I questioned the previous owner about the frequency with which he changed the zinc he stated, "Oh, they (the heat exchangers) don't have them anymore." Idiot. When I first checked there was nothing left but the brass plug fitting...
 
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rwthomas1

Sustaining Partner
When you find the zinc and remove it, or likely the brass plug, don't just install an off the shelf pencil zinc. On my 5432 HX, the use of a full length zinc will contact the cooling tubes inside, tightening it will likely rupture them. The zincs, at least in my case must be cut down a bit. Proceed with caution. RT
 

mherrcat

Contributing Partner
When I first changed my HE zinc I thought, "There's no way that 2" zinc is going to fit in there" so I cut 1/2" off. Later on I discovered that it did fit without cutting; at least the size "00" that my HE uses does. One other thing to note, do not put Teflon tape or any kind of pipe sealant on the plug threads. The zinc has to make an electrical connection and the tape could insulate it and prevent it from functioning. The tapered threads on the plug will keep it from leaking without the need for any sealing.
 

our38

Member II
Zinc

Well, the good new is, I found the heat exchanger zinc AND was able to remove it. The bad new is (for me anyway), when I went to screw a new one back in (i put an allen wrench in to measure the depth and found that the 2" '00' I purchased would fit), after only a few turns, the darn nut that's welded onto the heat exchanger deteriorated and the new zinc & nut (or parts of it) just fell in to the bilge. Now, I have a hole100_3317.jpg100_3311.jpg

shaped like the old nut that was welded to the heat exchanger . Now, my new question it, do I get a new nut welded to the heat exchanger? OR, do I have to find a new 2" diameter heat exchanger? A couple things about the one and only experience we had with the engine; we took the boat out a couple days ago for our first time out sailing, and it was great. I was surprised that the engine stayed so cool, it only heated up to about 140-150, and I expected it to be much hotter based on what other folks are saying. The engine sounded great and ran great, but when we went over about 2200 RPM's we started to get a little white smoke out of the exhaust, so I throttled down under 2200 and everything was great. With the sails up we were doing about 7.1 knots in no time (after we shut the engine off), and with the main and the jib out.

If I have to find a 2" diameter heat exchanger, where do I look? I disconnected the two top hoses today, but couldn't get the lower hose near the where the zinc goes; I'll work on it again tomorrow. If I change the size of the heat exchanger to 3", does anything else need to change? I haven't been able to run the engine for long periods of time, since the boat is new to us, AND we only took the boat out once before I ran in to this problem.

As always, any information would be much appreciated.
 

Guy Stevens

Moderator
Moderator
Call these people and get a new one

SEAKAMP ENGINEERING INC

360-734-2788

3985 Hammer Dr
Bellingham, Washington 98226-9153 , USA

http://www.seakamp.com

Fax: 360-671-0658

Tell them Guy Stevens sent you.

The price should be fairly reasonable. I am concerned with either the thickness of the wall on your old one, or the fact that you could not stabilize the fitting without ripping it out of the exchanger.

The old one appears to have been badly corroded.

Engine temp is controlled by the thermostat, not the size of the heat exchanger. That temp seems fine to me.

Was it white smoke or steam? Steam indicates that your exhaust temp is too high. Black smoke is from overloading the engine, and blue smoke is generally from burning Oil.


Guy
:)
 
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mherrcat

Contributing Partner
You would be better served to buy a new HE. If it was corroded badly enough for the zinc fitting to come off it is probably not worth trying to repair. The internal tubes in the HE may also be compromised. The HE is not steel but copper or some kind of alloy; those fittings are brazed on I believe.
 

our38

Member II
Mark, I think you're right about not worth being repaired. I'll call the place Guy suggested on Monday to see how long it will take to get a new heat exchanger.

Guy, I'm quite certain it was white smoke, not steam, and it only occurred at (or around) 2200 RPM's. The engine sounded real good, and the new Campbell Sailor prop seemed to be pushing us along quite nicely.

BTW, when I disconnect the last hose from the bottom of the Heat Exchanger, am I going to get a lot of coolant out of that line, or will it be sea water?
 

mherrcat

Contributing Partner
Not familiar with your engine but on mine the sea water goes in the HE on the bottom on the starboard side and out the top straight fitting on the same side. Coolant goes in the bottom on the port side and out the top 90 degree fitting on the starboard side. I believe I drained my engine coolant before removing the HE. I was looking at the Seakamp site when I removed my HE thinking I might need a new one, but mine was fine; just needed to be cleaned and a new gasket. Marine Diesel Direct (Torresen Marine) is OK for researching part numbers, but you can usually find better prices from other places on the net -- like Seakamp.
 

toddster

Curator of Broken Parts
Blogs Author
Hmm... the fog begins to lift a bit. Maybe. Last year I rehabbed my old H/E. There is a nut welded at one end with a little brass plug in it, but... no hole behind it. What the heck? I didn't figure it out at the time. Could they have left installation of a zinc anode as an option, and if the user wants one you need to drill your own hole? Without messing up the threads, somehow...

photo.JPG
 

mherrcat

Contributing Partner
There are so many different engines and heat exchangers to go with them it's hard to make a difinitive statement as to what's going on, but I would guess that no one ever changed that zinc and it completely disintegrated. The hole is probably plugged with hardened crud. You could try chipping it out or drilling without damaging the threads, as you mentioned. There are tapered taps for cutting NPT threads; you could try chasing the threads with a tap after drilling or chipping out most of the crud. I believe that fitting is 1/8" NPT.
 

our38

Member II
Heat Exchanger

Looks like the HE I have was originally made by SEN-DURE. I called them, and they said it was about a four week wait, YIKES!

SEAKAMP (nice folks) sent me to Outboard Motor Shop in Oakland. They don't have the 2" 299049 in stock, but might have the replacement 3". I know some of you mentioned the 3"; since I think the engine was staying cool with the 2" (I could be mistaken), what is the benefit of switching to a 3", or, should I just switch to the 3" for whatever reason since I have to replace this thing anyway?

Since I know nothing about any of this, I'm relying on all the information that's coming in, so thank you all very much for being there.

BTW, I also spoke with someone at LENCOCOOLERS.COM and they said they could send out a 299049 replacement in just a couple days.

So, do I go with a 3", or stay with the 2"? Attached is a picture of what started this whole thing.

IMG_0076.jpg
 

rwthomas1

Sustaining Partner
I went digging through the old receipts and I purchased my replacement heat exchanger from Lenco. I have the 3" unit, Lenco part number from the invoice is LE299835 and it was a direct replacement for the unit on the 5432. I paid 338.98 back in '07. Its still working just fine.

FWIW, the 3" has more cooling capacity. Do you need it? Good question, I know the 5432 was upgraded to the 3" unit, the M40 which is just a more modern 5432 has the 3" as well. I'm guessing 5432's had a reputation for running hot. Universal increased the size of the heat exchanger from 2" to 3" and they changed the raw water pump from an Oberdorfer to a Sherwood. Thats not to say a 5432 won't run fine with a 2" HX and an Oberdorfer, it may. But the uprated HX and raw water pump increase the capacity of the system and there had to be a reason for it.... Incidentally, if you have an Oberdorfer there is a replacement cam that will double the output and it will almost match the much more expensive Sherwoods output.

I might be the only person on this board that has actually taken a 5432 apart? I had one fail and replaced it with a used engine that was disassembled and thoroughly checked before being regasketed and installed in my boat. I have some "experience" building drag engines and messing with diesel engines and I can tell you the 5432 (its a Kubota) is a very well made and robust engine. The only way you will hurt one is to neglect it. Clean oil, fresh fuel, keep it cool and it will deliver reliable performance for many, many years.

RT
 

our38

Member II
Heat Exchanger

Rob, did the 3" fit in the same cradle, or did you have to get a new one? Is the 3" as long as the 2", that is to say 3"x16"? Will I have to change any of the hose sizes, AND do I HAVE to change the pump, or can I just leave it the way it is? Remember, I'm very new to all this, so I just want to get it done and go sailing, but I don't want to have a problem once I'm out there.
 
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