gear oil cooler Hurth Cummins 5.9

[bshanafelt]

I am in the process of doing the 2000 hr maint. on the motor and gear. My 5.9 is rated for 210hp, it has a turbo and is mated to a Hurth (ZF) model 63 gear.

If you have this gear or one that uses an oil cooler without a zinc, you will want to read on.

One of the tasks is to inspect the oil cooler for the tranny. As I was also replacing raw water hoses, this was a pretty easy matter of getting to the unit and removing it for inspection.

One odd thing I had noticed, but never worried too much about was the lack of a zinc for this cooler.

It is about 15" long and 2" in diameter. It also has a drain plug. I have never drained it.
I noticed some green mush around the plug and went to remove it when instead it popped(snapped) off.

So, I did a bit of internet snooping and found to my horror that this is a throw-away part - one is lucky to get 6 years out of it before needing to replace. Of course, a catastrophic failure would mean pumping raw water through your tranny - very un-cool.

My motor & gear is 14 years old - I think I got my $$ worth out of the stock cooler.


New cooler in cupro-nickel from Fisheries is $109 - Gonna get a spare and plan to change it out at the 5 year mark. Sure wish there was a way to hang a zinc on it.



So, if you have one of these NON-zinced coolers, watch it.

 

[Nomad Willy]

Ban,
Why don't you just get one w a zinc port? My Trans cooler is about the same size w 40hp and a BW rear. Actually I think it's bigger. The cooler was put on during my repower (done by Klassen in Ballard) and I'm sure they have a cooler at a good price. Mine has a drain plug (threaded) also. Yours being cupro-nickel may be superior though.

 

[SteveH]

Does your cooler look something like this?

 

[bshanafelt]

here is a picture of a similar unit. Not very complex, nor does it look like it would be too dificult to manufacture with another boss for a zinc.

Eric has a good idea to try and find a similar sized cooler that uses a zinc.

 

[O C Diver]

Why can't you use the drain plug hole for a zinc? When the cooler on my 300 C Cummins started to leak water into the boat, the local dealer said they bought trans coolers from the same company that Cummins does. The difference (besides 2/3rd of the cost) is there is a spot on the end casting to drill and tap for a 1/8" pipe plug pencil zinc.

BTW, from experience, the salt water generally doesn't go in the transmission as the oil pressure in the trans is likely 10+ times higher. Your transmission oil gets pumped into the raw water system and out your wet exhaust. Visualize a 1 gallon oil slick.

Ted

 

[sunchaser]

Two years ago a hose takeoff from my cupronickel engine HX corroded away. The HX, designed with no zincs was fine, the nipple failed. There have been many complaints about Cummins gear coolers on boatdiesel. Some suggested ways to mimize TX - HX issues:

• Do as bshanafelt did, inspect every 5 years or so
• Avoid salt water drips
• Check your TX oil visually every day before you run the vessel
• Replace zincs routinely if you have them
• Keep TX - HX clean

Any others?

 

[Nomad Willy]

Stupid me,
I just had to cut my whole post. I've been confusing engine coolant cooler and trans oil cooler. No wonder everybody's cooler seemed too small.

My trans oil cooler has no zincs either and for several months I've been thinking I should at least call Klassen and try and determine when I should replace it. It's been on there for 7 years so I'm due too.
Re the size of the cooler and the fact that I've always wondered why the engine coolant cooler had a zinc and the trans oil cooler did not it just occurred to me that theres probably just isn't room for the "pencil" zinc in the small trans cooler. I wonder if bigger boats have the zincs.

Oc,
The oil pressure would keep the sea water out only until the oil amount and pressure got low. Then the sea water would get into the trans.

sunchaser,
You're #1 should read "Replace coolers regularly according to established frequency declared by your engine manufacturer or find the best substitute."

Now I wonder how long my engine coolant cooler should last.

 

[RT Firefly]

Greetings,
Having no idea of scale in the picture Mr. bsh' posted I will assume the tranny cooler pictured is of a similar size to what is installed on my Lehmans which as well as being being cupro-nickel DO include both a drain and facility for a zinc. There is also a grounding stud which I tied onto the engine block.
Interesting point....When I replaced the heat exchangers some years back (with Cu-Ni) the "old" units were grounded by means of the mounting flanges. The replacement units used a plastic/phenolic mounting system and a grounding stud.
I will admit I have been remiss in regular zinc maintenance in aforementioned units and when I DID service the zincs this past summer they were well wasted. Hopefully no damage had been done (3 year time frame). Me bad...
Now, all that being said, I had to saw off about 1" from available zincs LENGTH to fit them in the restricted tranny cooler. OD was fine.

 

[bshanafelt]

The Leman cooler is a very nice unit - couple of zinc holes if wanted or one zinc and one 'ground'.

If this was available in a 1 1/4" raw water connection instead of the 1" it would be the perfect substitute for the cummins/hurth unit.



concerning adapting the stock unit:
I am pretty sure that a pencil zinc small enough - does not exist which would fit into the drain hole plug - it is really small, maybe 1/4 NPT, but I will see if Fisheries has such an animal.



The stock cooler is around 15" in total length - 2" diameter.

 

[fryedaze]

SteveH, is that the reflection of a persian rug in the picture you posted. That sure is a puurrdy engine room.
Dave

 

[SteveH]

Thanks for the compliment... A Persian rug would be a fine addition to the ER...., but I must admit my cheep remnant (used to help save the knees while crawling around) is a far cry from such opulence.

Steve

 

[O C Diver]

I am pretty sure that a pencil zinc small enough - does not exist which would fit into the drain hole plug - it is really small, maybe 1/4 NPT, but I will see if Fisheries has such an animal.

The boat yard I haul out in stocks pencil zincs down to 1/8" pipe thread. If yours doesn't, you can order them here:

Pencil zinc 1/8" mpt.Ted

 

[O C Diver]

Oc,
The oil pressure would keep the sea water out only until the oil amount and pressure got low. Then the sea water would get into the trans.

When the oil pressure falls to zero, most transmissions go to neutral, potentially a much bigger problem depending on what you are drifting into.

Ted