Re: Bowman DC60-XCC Transmission Oil Cooler Failure; ZF Hurth ZF 25; Yanmar 4JH3-HTE #lessons


Scott, I have not known that valve to leak. It generally gets exercised more than any other on an Amel

CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
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On Thu, Aug 26, 2021 at 2:00 PM Scott SV Tengah <Scott.nguyen@...> wrote:
Thanks Bill and everyone else.

As an aside, the stopcock on my sea chest allows a tadbit of water through even in the closed position. Has anyone ever experienced this? Could it be a bit of growth in the stopcock itself? 

Normally it's not an issue since either the stopcock is open or it "leaks" into the sea itself, but given that I'm going to replace my oil cooler soon, I'd rather not have a slow trickle of saltwater into the engine room when the hoses are disconnected.

On Thu, Aug 26, 2021 at 5:16 AM Matt Salatino via <> wrote:
Looks like this?


On Aug 26, 2021, at 6:06 PM, CW Bill Rouse <brouse@...> wrote:

Yep, I could not find C9 made by Mota

CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar

On Thu, Aug 26, 2021 at 10:03 AM Matt Salatino via <> wrote:
Looks a bit different than that. Says “C9” on it.


On Aug 26, 2021, at 6:00 PM, CW Bill Rouse <brouse@...> wrote:


Thanks for that. It is likely this cooler:

Tubestack diametre (Ømm) 58
Connection on cold side Ø52mm hose
Connection on hot side G3/8" (BSP) thread
Tubes material Copper-Nickel (CuNi10)
Headers material Brass
Housing material Extruded aluminium

CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar

On Thu, Aug 26, 2021 at 9:42 AM Matt Salatino via <> wrote:
It’s got the word “mota” stamped on it.


On Aug 26, 2021, at 5:22 PM, CW Bill Rouse <brouse@...> wrote:

For A55 owners and possibly A50 owners (an A50 owner please verify)

There is a different oil cooler that Amel used in the A55 (possibly all hull numbers). I am not sure of the brand, but the same thing applies to the end closest to the sea chest. Here is a photo of the oil cooler on the A55.

CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar

On Thu, Aug 26, 2021 at 8:55 AM Bill Rouse <brouse@...> wrote:
Scott, same Bowman cooler on Yanmar SMs and 54 D3s.
It is very important to inspect the end of the cooler nearest the sea chest. This is where debris will accumulate and reduce water flow. According to Bowman the number 1 failure of the Bowman Cooler is the overtightening of the boot hose clamps on each end. The metal is soft enough that a overtightened hose clamp will squeeze the tubes closed.

Here is a short story for many Amel owners. I had a client who had purchased my Amel Book and 24/7 Support. After about 5 years he decided to sell his Amel. When it was being surveyed the surveyor insisted on running the engine at WOT, the Onan, the water maker, and 3 Air Conditioners. The engine overheated. The surveyor's conclusion was that the Amel sea chest and manifolds were inadequate. My client called and was very distressed. I suggested to him that the Bowman oil cooler had debris inside the boot nearest to the sea chest. Nobody agreed with me and thousands were spent. The sea trial was done again under the same circumstances. The engine overheated again. This time the client removed the large clamp on the end of the Boman Cooler nearest the sea chest and found it full of debris. In 5 years he had never done this, although I recommended it and it is in my book. The moral of this story is easy to figure out. The page from my book is below.

CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar

On Thu, Aug 26, 2021 at 4:27 AM Mohammad Shirloo <mshirloo@...> wrote:

Hi Mark;


Thank you for sharing your experience. We removed and had all of the heat exchangers professionally cleaned in 2018. However, it is not possible to identify wear. Therefore I’d like to order a couple of the heat exchangers and replace ours and have one as spare. It is hard to read the part number on the cooler, without removing it.


Does anyone know if all A54s used the same part number too, or are there different parts for different hull numbers?





Mohammad and Aty

B&B Kokomo

Amel 54 #099


From: <> On Behalf Of Mark McGovern via
Sent: Thursday, August 26, 2021 12:41 AM
Subject: [Special] [AmelYachtOwners] Bowman DC60-XCC Transmission Oil Cooler Failure; ZF Hurth ZF 25; Yanmar 4JH3-HTE #lessons #lessons


In the spirit of Pat from Shenanigans "Lessons Learned" post a few week's back I thought I would share what I learned when my Bowman DC60-XCC oil cooler failed while motoring up the coast of Maine a few days ago.  Thankfully, we caught the failure relatively early in large part due to the fact that when cruising in Maine you have to remain hyper-aware at all times because of the lobster pots that are literally all over the place including in marked channels and anchorages. Because of that, both my wife and I were in the cockpit doing nothing but looking out for lobster pots and calling out their positions to whomever was at the helm. There were no podcasts, no music, no book reading, no headphone, just hyper-vigilance with two people, 4 eyes, and 4 ears on watch at all times. 

The first symptom we noticed was what sounded like a slight misfire of the engine.  It sounded like the RPM increased ever so slightly for just a second.  It was just a "blip" and was not large enough to actually even register on the tachometer.  After hearing it a few times, a minute or so apart, I asked my wife if she was hearing it. She said she was. My first thought was a clogged fuel filter despite the fact that my last fuel fill ups were from fairly busy harbors in Annapolis, MD and Onset, Massachusetts and that we had only ~60 hours on the Racor filter.  In addition, the RPMs of the engine seemed to increase not decrease like I would expect from fuel starvation from a clogged fuel filter.  In any case, I switched over to the second Racor but the occasional engine “blip” did not go away. In fact it got more frequent and it actually started to register on the tachometer just barely.  I put my head over the side to take a look at the engine exhaust.  I did not see any white or black smoke coming out of the engine exhaust.  However, I did see an oil slick trailing behind us the likes of which I have never seen before.  My immediate thought was that the engine oil cooler had failed and was leaking engine oil into the raw water system.  We had no choice but to shut the engine down ASAP.  There was only 6-7 knots of wind directly behind us but we also had a bit of favorable current so we just put out the main sail, turned off the engine and called Towboat US.  We are not at all familiar with this area and we did not see any decent anchorages looking at the charts. We were only 2 nm from our destination of Belfast, Maine and the Towboat captain said it would take him about an hour to meet us at the entrance to the harbor.  So we sailed at 1.5-2 knots with just the Main and met the Towboat captain at the entrance to the harbor where he towed us the last mile to our mooring ball where we still sit right now waiting for our replacement oil cooler to arrive from the UK.


Once we were safely moored, I went down to the engine room to check the oil in the Yanmar.  It was perfect.  Not a drop appeared to be missing.  After a brief “wtf?” moment, I checked the transmission dipstick.  The fluid level did not even register on the dipstick at all.  However, I could see that there was some ATF left in the transmission case.  That was a bit of a relief but not much.


All of this happened on a Saturday and I do not carry a spare oil cooler so I would have to wait until Monday to order a replacement.  First thing Monday morning I started to call all of the USA dealers for Bowman marine products listed on Bowman’s website.  Of those who actually answered the phone, none of them had the DC60-XCC in stock or even just the DC60 (oil cooler with no end caps). One actually told me that he didn't think DC60-XCC was a valid Bowman part number. I said “I’m looking at their catalog online right now.  It is.”


I then called Bowman in the UK and asked if they knew anyone in the USA who might have one of these in stock and they hesitated and said the only one who might have one is Tradewinds Power Corporation.  When I had previously called Tradewinds Power Corporation they said "our computer system is down right now" so we will need to call you back.  They never did.  

Luckily, I had also asked Bowman who in the UK would definitely have them in stock and would ship to the USA.  Without hesitation, they told me that Lancing Marine will definitely have it and they ship around the world.  So I called Lancing Marine ( and had a wonderful experience buying from them.  Not only were their prices the lowest by far that I had seen anywhere online (79 GBP/~109 USD including new couplers) but the ordering experience was fantastic despite it being phone order only.  The person I spoke to also obviously knows these transmissions well.  His name was Mike and I'm pretty sure he is the owner and founder of the company - founded in 1970!  He gave me his opinion on the state of my transmission (he thinks it’s probably fine) and advice on how to test it to see even before the replacement cooler arrives.  On top of all that, despite it being about 3pm their time when I called, the coolers (I ordered a spare) shipped out the same day.  Last, he said that if I do need to get the transmission rebuilt, that he would highly recommend a company in the lower Chesapeake Bay called Transatlantic Diesels. He says that they know these ZF transmissions better than anyone and he has done business with them for years.  It was really just a great overall buying experience that seems to be so rare in these days of anonymous Amazon purchases.


The moral of the story is that for ~$109 plus shipping and an hour of my time I should have replaced the transmission oil cooler PROACTIVELY soon after I bought the boat back in July 2017.  Especially given that I did not know the age of this critical part.  Or I should have replaced one of four times that I have replaced the transmission fluid.  At the bare minimum, I should have had a spare oil cooler already on board.  The engine, and I assume the oil cooler, just surpassed the 2000 hour mark.  Researching this site after the fact I found at least two other SM owners who had the same failure at around the 2000 hour mark. Both, I believe, lost their transmissions.  Hopefully, I have not. I will know in a few days time.


So in the spirit of the #lessonslearned, don’t be like me.  If you are not sure how old your transmission oil cooler is, replace it.  If it’s approaching 2000 hours, replace it.  At a minimum, get yourself a spare oil cooler.  And if you can’t find it locally, get it from the nice people at Lancing Marine in the UK so that we all have at least one place in the world that keeps these things in stock.


Mark McGovern
SM #440 Cara
Deale, MD USA

2007 A54 #69
SV Tengah

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