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Yanmar 3JH4E overheating

Printed From: myHanse.com
Category: Hints & Tips
Forum Name: 400
Forum Description: 400 Hints, Tips and News
URL: https://www.myhanse.com/forum_posts.asp?TID=10446
Printed Date: 28 March 2024 at 12:46
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com


Topic: Yanmar 3JH4E overheating
Posted By: jensenflemming
Subject: Yanmar 3JH4E overheating
Date Posted: 11 September 2017 at 21:10
Hello!

I have a Hanse 400e from 2005 with the Yanmar 3JH4E engine that is overheating.

I used to be able to run 2500 rpm for hours but now I can only run it at 2000 rpm for longer periods of time. 2100 and the to hot alarm will go off within an hour

Is it the heat exchanger that needs to be fixed? I see okay flow of seawater in the exaust...

I have blue coolant and have actually never replaced the coolant. (Have had the boat for 5 years)

I can see that you can buy Yanmar coolant that is premixed and ready to use.

But is red coolant G12+ also fine? or G12++?

How do I drain the engine for coolant? In the manual I can read that there are drains on both sides og the engine but also on the front behind the belt cover?

Do I need to drain all of them?

Do you mix the coolant with demineralized water 1:1?

Looking forward to some helt in this field

BR



Replies:
Posted By: Borjebus
Date Posted: 12 September 2017 at 10:06
You should check if pieces of the impeller got lose and is now clogging the heat exchanger.
There are a number of threads about this topic ...


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BÄSK, Hanse 370e #82 from 2006, Yanmar 3JH4E/SD50, 3-blade Flexofold, RMC(Lewmar) 185 Bowthruster, Vulcan 9, Simrad+B&G instruments


Posted By: Peter-Blake
Date Posted: 12 September 2017 at 10:20
I echo Borjebus.

1. check your impeller
2. If you never changed it, do it now! Find missing parts!
3. If your motor has more than 1000hrs, than the heatexchanger may need a good cleaning!
4. If your coolant is the old blue/green stuff, than this is possibly the original coolant......This has to be changed every 2-3 years. The pink stuff lasts longer. Old coolant (no matter what colour) has a reduced rustproofing. It still cools your motor, but for rustsafety you should exchange it.


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Blake 370


Posted By: Rubato
Date Posted: 12 September 2017 at 18:09
Also check the raw water intake and strainer/filter. The answers to most of your questions can be found in the service manual.

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Steve

Hanse 400e, #168



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