Yanmar coolant filler neck loose

[Celestialsailor]

I used JB Weld as a "temporary" fix on the thermostat housing on my Westerbeke W46. I bought a new/used housing but never put it on. that was 5 years ago and going strong.
Just empty some coolant out, wire brush the area to bare metal and acetone a few times. then apply JB Weld.

[Ocean Sky]

Originally Posted by TFlight

I own a 2007 Yanmar 4JH4E with the same small annoying coolant leak around the base of the pressed in filler neck. Yanmar sent me a copy of a Tech Bulletin for replacing the filler neck. see attached.

I was wondering if the sealant around the Filler-Neck worked for you?
I'd like to try that first and if it doesn't work I'll replace the filler neck as per the Yanmar Tech Bulletin or replace with a flange type filler neck.

Also in regards to the earlier post showing the bolt on filler neck with the flange from an older engine, any idea what engine, year, or model that came off of?

Thanks,
TFlight

i am back om the boat...and i have easliy just pulled out the complete filler next ,with the copper ring inside it.It does not appear to be cracked at all so have cleaned it up with wire brush etc .

Yanmar manual says to first apply an activator T4741 to both surfaces then apply Loctite 603 which is not a metal epoxy ( more of a high strength retainer/sealant for 2 cylindrical surfaces),and reinsert it...i will try to locate these products first and try that ...it came out quite easily so i hoping i will not need the special tools for pushing it back in again.

If this does not work then i will resort to the JB Weld ,although that is not what is recommended in the manual.I am a bit concerned that if i just use the JB Weld then it might be impossible to take the filler neck out again in future..would be really stuck to the heat exchanger...

https://www.manualslib.com/manual/12...age=294#manual

Let you know how it goes!

[Ocean Sky]

A quick update:

We just cleaned up the filler neck with a wire brush, light sandpaper,then wipe with Acetone. Could not source the activator Yanmar talk about but i think the Acetone probably acted like one in some way.

The Loctite 603 is green and very thin and liquid,just needed a few small drops on the part of the filler neck where it pushes down into the heat exchanger then pressed it in easily by hand with a light tap just to make sure.We did not dismantle the copper insert as it all looked ok,and surprised how easily it went back in.It was probably the original Loctite still on there from new in 2007 ,so it did ok for 10 years!

Waited 24 hours ,and started her up to running temperature,dry as a bone and no leak!

So ,so far so good , will update if any further problems occur.

Many thanks to all who offered their great advice /information.

[NYSail]

Originally Posted by Ocean Sky

A quick update:

We just cleaned up the filler neck with a wire brush, light sandpaper,then wipe with Acetone. Could not source the activator Yanmar talk about but i think the Acetone probably acted like one in some way.

The Loctite 603 is green and very thin and liquid,just needed a few small drops on the part of the filler neck where it pushes down into the heat exchanger then pressed it in easily by hand with a light tap just to make sure.We did not dismantle the copper insert as it all looked ok,and surprised how easily it went back in.It was probably the original Loctite still on there from new in 2007 ,so it did ok for 10 years!

Waited 24 hours ,and started her up to running temperature,dry as a bone and no leak!

So ,so far so good , will update if any further problems occur.

Many thanks to all who offered their great advice /information.

Hello.......

I too have the yanmar 4JH4E and am seeing the leak at the base. How is your repair going so far?? I plan to do the fix this off season. Any suggestions / advise or is it pretty straight forward??
Thanks
Greg

[Ocean Sky]

Originally Posted by NYSail

Hello.......

I too have the yanmar 4JH4E and am seeing the leak at the base. How is your repair going so far?? I plan to do the fix this off season. Any suggestions / advise or is it pretty straight forward??
Thanks
Greg

Hi Greg

Yes after 18 months no problem at all .

As i mentioned i could not find the Activator mentioned by Yanmar but the Acetone worked ok.

The Loctite 603 was easy to apply ,everything was surprisingly easy.

So i would just just follow the manual .

Have done about 100 hours since then,so fingers crossed!

let us know how it goes.