SailNet Community - Reply to Topic
Thread: Yanmar losing coolant Reply to Thread
Send Trackbacks to (Separate multiple URLs with spaces) :
Post Icons
You may choose an icon for your message from the following list:

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

  Additional Options
Miscellaneous Options

Click here to view the posting rules you are bound to when clicking the
'Submit Reply' button below

  Topic Review (Newest First)
07-02-2013 10:54 PM
Capt Len
Re: Yanmar losing coolant

My vote is to replace heat exchanger .Make sure the sacrificial zincs in it are good and maintained.
07-01-2013 12:58 PM
Re: Yanmar losing coolant

whatever happened on your heat exchanger? I'm having some weird issues and suspect the HE so was searching the threads and found this one.
09-14-2011 11:03 AM
Originally Posted by JimsCAL View Post
Heat exchanger would be my guess also.
09-14-2011 12:08 AM
JimsCAL Heat exchanger would be my guess also.
09-13-2011 05:07 PM
dabnis "System slowly lost pressure", Possibly coolant leaking into the raw water side of the heat exchanger? Or small leak in the head gasket?

09-13-2011 02:17 PM
Tim R.
Yanmar losing coolant

Here is what I know:

Engine is a 14 year old Yanmar 4JH2E with 2000 hrs.

- Earlier in the season the engine would use a few ounces of coolant when I ran it about an hour or 2
- Now suddenly the coolant is disappearing at the rate of appr 64 ounces per hour
- No sign of coolant in the oil.
- No sign of oil in the coolant.
- No sign of coolant in the bilges or under the engine.
- Engine otherwise runs perfectly. Good power and smooth operation. Starts on first try.

Last night I performed some diagnostics with a pressure tester. Here are the results:
- Engine off, system pressurized to 16lbs, tester slowly lost pressure. Started the engine and AF came out the exhaust. Took a few tries to start.

- Refilled system, connected tester, started engine. No jump on the tester. If the gauge suddenly jumped up it could indicate a head gasket problem.

- Engine running, pressurized the system to 16lbs and needle did not jump around. If it did it could indicate cracked head or block. System slowly lost pressure.

I am thinking bad heat exchanger. I will pull it tonight to check.

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

For the best viewing experience please update your browser to Google Chrome