Yanmar heat exchanger leak?? - SailNet Community

   Search Sailnet:

 forums  store  

Quick Menu
Boat Reviews  
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Hatches and Portlights
Interior And Galley
Marine Electronics
Other Items
Plumbing and Pumps
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here

Go Back   SailNet Community > On Board > Gear & Maintenance > Engines > Diesel
 Not a Member? 
Old 07-01-2013
But if not...
Join Date: Sep 2011
Location: Annapolis MD
Posts: 123
Thanks: 0
Thanked 7 Times in 7 Posts
Rep Power: 4
paperbird is on a distinguished road
Yanmar heat exchanger leak??

I have a 1996 4jh te (serial #12285) and think the heat exchanger may be compromised. Hereīs what happened. Started with a big mistake - we tried to fill the hot water heater heat exchanger lines at the hot water heater using a hose and a T fitting. (hot water heater is above the engine). We heard fresh water running into the exhaust system at the water muffler. As soon as we heard it, we turned off the water and realized there was a serious problem. Ended up pulling the injectors, shutting off the fuel and then slowly turning over the engine. Sure enough - water was forced out of the injector ports. Since it was all the ports, not just one, Iīm assuming the head gasket is OK and the water got to the cylinders via the exhaust valves.

Reinstalled the injectors and then started the engine. Ran fine. Let it run for 1/2 hr, shut it down, then repeated a couple times to make sure all the water was out and everything is running OK.

My guess is the heat exchanger is compromised allowing fresh water to cross over to the raw water side and into the exhaust system. I canīt think of how else water got into the exhaust system. By using a hose (~30psi) I forced fresh water across to the raw water side, into the water muffler and then back up into the engine through the exhaust. Dumb, but inadvertently found a problem I didn't know about.

Other data:
- coolant level in the heat exchanger does not drop
- no visible leaks into the bilge
- no water in oil
- no detectable levels in any of the fluids (water, oil, transmission, etc)
- engine runs fine, does not overheat

- how do I test the heat exchanger?
- what else could allow water into the cylinders
- if itīs the heat exchanger, do I need to replace the core or the whole assembly?
- If just the core, what else should be checked/replaced at the same time?
- what am I not asking that I should be asking?
Reply With Quote Quick reply to this message Share with Facebook
Old 07-02-2013
Senior Member
Join Date: Oct 2011
Location: Nanaimo B.C.
Posts: 2,292
Thanks: 3
Thanked 45 Times in 45 Posts
Rep Power: 4
Capt Len is on a distinguished road
Re: Yanmar heat exchanger leak??

What if you disconnect raw water out at the injection point of the exhaust and try it again. I see two options .. Youv'e misidentified the ins and outs raw and fresh or the core is about to tell you something.Look out for air lock in hoses above the expansion tank and pressure sensitive tank cap .A good run at temp to remove the last of the water in oil.
Reply With Quote Quick reply to this message Share with Facebook

heat exchanger , yanmar

Quick Reply

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

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.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Yanmar 2gm20f heat exchanger jerzy0129 Diesel 3 01-03-2014 12:41 PM
Yanmar Heat Exchanger/Exhaust Elbow CapnRon47 Gear & Maintenance 7 11-06-2012 08:04 PM
Yanmar 2GM20F Heat Exchanger arf145 Diesel 3 05-10-2011 03:43 PM
Yanmar Heat Exchanger Hunterdon31 Diesel 5 11-24-2009 10:29 PM
Yanmar Heat Exchanger Problem? AlanBrown Gear & Maintenance 5 05-06-2008 10:00 PM

All times are GMT -4. The time now is 02:39 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2015, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.