Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 09-06-2018, 00:54   #1
Registered User

Join Date: Oct 2012
Posts: 33
Coolant temperature at idle rpm on Yanmar 4JH5E

Hello everyone,

I transfer here my previous thread regarding my false-diagnostic on my Yanmar 4JH5E.

So here are the facts :
- Yanmar 4JH5E installed new in 2011. 1500 hours now
- After 25-30 minutes at idle rpm (around 800 rpm) the temperature alarm fires
- When navigating, there is no problem (Done 6 or 7 hours trip)
- No suspicious smoke
- Checked the impeler (recently changed anyway), OK
- Cleaned the raw water strainer, and the water at exhaust seems in reasonable volume
- The temperature at the top of the engine during those 25-30min clearly rises, and is too hot to touch at the end
- At exhaust, the water spit by the engine is suspectedly cold ... this water is not cooling the engine ...

Any clue where should I start from ?
Why only at idle ?
Thanks everyone
Jaad
__________________

jjorio is offline   Reply With Quote
Old 09-06-2018, 01:14   #2
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 8,753
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

Partial blockage in the Heat Exchanger (either coolant or raw water side) perhaps.

Happens at idle because the water pump (coolant or raw water) is not pushing enough coolant or raw water past the partial blockage when engine is idling ?????

More likely to be the raw water side IMHO although you seem to be getting a reasonable flow.

Until you better advice, try inspecting the heat exchanger...
__________________

__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is online now   Reply With Quote
Old 09-06-2018, 01:33   #3
Registered User

Join Date: Oct 2012
Posts: 33
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

Thank you for your suggestion.
But what about the temperature of the discharged water at exhaust ?
It should be at least warm in normal conditions ?
jjorio is offline   Reply With Quote
Old 09-06-2018, 01:38   #4
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 8,753
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

Quote:
Originally Posted by jjorio View Post
Thank you for your suggestion.
But what about the temperature of the discharged water at exhaust ?
It should be at least warm in normal conditions ?
Which is why it might be the coolant side of the heat exchanger that is partially blocked although this is less common.

Is the discharged water warm when the engine is running at speed under load?
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is online now   Reply With Quote
Old 09-06-2018, 01:39   #5
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 8,753
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

Can you see if the coolant is circulating when the cap is removed?
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is online now   Reply With Quote
Old 09-06-2018, 01:41   #6
Registered User

Join Date: Oct 2012
Posts: 33
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

Quote:
Originally Posted by Wotname View Post
Is the discharged water warm when the engine is running at speed under load?
I'll test it in the next days. Unfortunately can't do it now ...
jjorio is offline   Reply With Quote
Old 09-06-2018, 01:47   #7
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 8,753
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

By then you might get smarter and better replies from others
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is online now   Reply With Quote
Old 09-06-2018, 01:48   #8
Registered User

Join Date: Oct 2012
Posts: 33
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

Quote:
Originally Posted by Wotname View Post
Can you see if the coolant is circulating when the cap is removed?
The engine is still hot, but acceptable temperature.
I tried to remove the cap, it turns, opens, but I can't remove it !!! seems to be blocked. (I didn't put too much force neither, don't want to break it ...)
I changed this cap (old was rusty) a few months ago ...

Also when I opened the cap, there was air pressure inside (like opening a pressure cooker / I had a protection on my hand of course)

The sub tank is quite full, and when I open the cap, the hose bubbles in the coolant contained in the subtank
jjorio is offline   Reply With Quote
Old 09-06-2018, 01:59   #9
Registered User

Join Date: Oct 2012
Posts: 33
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

There is also this :
Check the picture of the impeller (as I said earlier it is only a few hours old), you can see that one of the wings (don't know how to say) are bent on the opposite side that the others.
Inlet of raw water is on the right side of the picture.
Outlet on the left

Something looks wrong ?
jjorio is offline   Reply With Quote
Old 09-06-2018, 02:03   #10
Registered User

Join Date: Oct 2012
Posts: 33
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

The picture
Attached Thumbnails
Click image for larger version

Name:	IMG_20180608_222224.jpg
Views:	189
Size:	171.7 KB
ID:	171310  
jjorio is offline   Reply With Quote
Old 09-06-2018, 02:05   #11
Registered User
 
MBWhite's Avatar

Join Date: Apr 2012
Location: Illinois
Boat: Hurley Alacrity
Posts: 374
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

No slight intended at all, but what you need to do next is buy an "IR (infrared) Thermometer"



You can get these for less than $10 off ebay, walmart, or amazon. Get one with a laser dot so you can see where it is pointing, and you can map pretty accurately what your engine temps are at and where. It works MUCH better than the old way of seeing how long you can hold your hand on something.
MBWhite is offline   Reply With Quote
Old 09-06-2018, 02:08   #12
Registered User
 
MBWhite's Avatar

Join Date: Apr 2012
Location: Illinois
Boat: Hurley Alacrity
Posts: 374
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

Quote:
Originally Posted by jjorio View Post
The picture
I don't think that is enough to cause an issue, but just rotate the engine by hand until that vane is on top where it has more room and flex it back the other way, either just with your fingers or use a pair of needlenose pliers.
MBWhite is offline   Reply With Quote
Old 09-06-2018, 02:08   #13
Registered User

Join Date: Oct 2012
Posts: 33
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

Quote:
Originally Posted by MBWhite View Post
No slight intended at all, but what you need to do next is buy an "IR (infrared) Thermometer"



You can get these for less than $10 off ebay, walmart, or amazon. Get one with a laser dot so you can see where it is pointing, and you can map pretty accurately what your engine temps are at and where. It works MUCH better than the old way of seeing how long you can hold your hand on something.
Thanks for that !
The problem is that this is impossible to find here. Need to order it and it takes a long time to ship here ...
Maybe other cruisers might have one. I'll check that in the morning.
jjorio is offline   Reply With Quote
Old 09-06-2018, 02:14   #14
Registered User
 
MBWhite's Avatar

Join Date: Apr 2012
Location: Illinois
Boat: Hurley Alacrity
Posts: 374
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

Out of curiosity, where are you located?

These are also often used in professional kitchens, so if you have a friend who works in a restaurant you may be able to borrow one there (they are used for checking temps of freezers and also ovens).
MBWhite is offline   Reply With Quote
Old 09-06-2018, 02:22   #15
Registered User

Join Date: Oct 2012
Posts: 33
Re: Coolant temperature at idle rpm on Yanmar 4JH5E

Quote:
Originally Posted by MBWhite View Post
Out of curiosity, where are you located?

These are also often used in professional kitchens, so if you have a friend who works in a restaurant you may be able to borrow one there (they are used for checking temps of freezers and also ovens).
I'm in Hiva Oa, Marquesas Islands 1200 persons living in the island.
Very remote
__________________

jjorio is offline   Reply With Quote
Reply

Tags
coolant, rpm, yanmar

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not 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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Yanmar 4JH5E Injection Pump Failure gmthompson99 Engines and Propulsion Systems 11 05-02-2018 12:17
Yanmar 4jh5e service / shop manual download Pwrybas Engines and Propulsion Systems 1 22-06-2013 03:49
Yanmar 4JH5E Gasket source? gbanker Engines and Propulsion Systems 3 19-12-2011 04:08
Perkins 4.108 Replacement with Beta 43 or Yanmar 4JH5E AbacoBahamaMan Engines and Propulsion Systems 2 06-08-2010 17:14
Engine idle woes-Will not idle after warm Pa La O La Engines and Propulsion Systems 5 24-09-2006 13:13



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 05:02.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.