Yanmar 3YM30 Heat Exchanger Removal and Cleaning

LVGS

LVGS

.
Apr 8, 2018
32
Hunter 33 Nanoose Bay, Vancouver Island
We have been experience overheating of our H33’s 3YM30 and have narrowed it down to either the mixing elbow or heat exchanger; perhaps both. I have purchased a new elbow and am confident that I can replace it. However, removal of the heat exchanger is keeping me up at night. The various Yanmar manuals that I have read do not provide sufficiently detailed ’how to’ instructions on removing the unit.

For those of you that have done it, any advice, detailed instructions or referral to instructional resources would be much appreciated. Thanks in advance for any input.
 
jssailem

jssailem

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Oct 22, 2014
21,081
CAL 35 Cruiser #21 moored EVERETT WA
LVGS, This video might be helpful. Here the owner has removed the assembly from his engine. He is taking the unit completely apart.

 
kloudie1

kloudie1

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Nov 6, 2006
9,892
Hunter 34 Mandeville Louisiana
I am not super familiar with that engine, but I think taking the tube bundle out is not that big of a job (if the nuts/bolts aren't frozen) . Drain antifreze, remove the alternator and exhaust ell,, pull the end caps and slide the tube bundle out .. Key is to have a new set of gaskets/o-rings before ya pull it apart.. Take some pictures so you can easily reassemble .. Note the little pegs (if any,; the GMF bundle has some to keep the bundle firmly in place) Good luck..
 
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seadaddler

seadaddler

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Dec 19, 2006
5,809
Hunter 36 Punta Gorda
OK I have 2007 3YM30 on my H-36 and what I have done is completely flush the system once or twice also
take end caps off of the heat exchanger check to see anything and I use the right size threaded rod in and out each hole and it did help run cooler but just changed the fresh water pump because had a leak and think it is running much cooler but have not taken it out cruising for a few days yet and put all new antifreeze and new impeller too
 
O

odaydokay

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Jul 5, 2011
702
Oday 28 Madison, CT
That is now 14 years old right? You may do a lot of work and wind up unhappy. Look at the hours and risk and compare to a new one maybe?
 
LVGS

LVGS

.
Apr 8, 2018
32
Hunter 33 Nanoose Bay, Vancouver Island
Thanks everyone, your feedback is very helpful and much appreciated.

I had the opportunity to spend approximately 30 min with the service manager at a Yanmar dealer earlier today. He was kind enough to to walk me through the process of replacing the elbow and checking the core ie. without removing it. These are my next steps to determining where the obstruction is located. In the event the core is plugged up, I will then drain the coolant and remove and either clean or replace the core.

I also bought a new anti-siphon as I do not know when, if ever, it was replaced...cheap insurance.

Thanks again and if you have any other words of wisdom please let me know.
 
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dave_and_dd

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Apr 13, 2015
156
Catalina 309 Port Charlotte
I have a 3ym20, so pretty similar. When i last replaced the mixing elbow, was easy to remove the heat exchanger end caps an used a rod to be sure the tubes were all clear. New O rings on the end caps and that was done.

Didn't try to take out the tube bundle.

Hope that helps....
Dave
 
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