EnginsOperating Temp 6BY260

N

Nellie Too

Well-known member
Joined
Jan 13, 2009
Messages
793
Fluid Motion Model
C-288 C
Hull Identification Number
86
Vessel Name
(2009) Nellie Too
Hello All,
A few weeks ago I was coming home and the engine warnings came on, the temp was showing 225'. I had the fresh water impeller replaced (which had been quite damaged) and also refilled the antifreeze. After all was done I became very attentive to operating temp and am very concerned about it. I am wishing to get some feedback about your normal temps so that I can compare mine. Currently at 1200 rpm it operates at 200', at 2200 rpm the temp rises to 205' and if I run it to work the turbo at 3600 rpm the temp rises to 213' ( think this is quite high and I am concerned). I called MER Equipment to price a new thermostat (comes as an assembly) the price is $137.00 but they said I could have it a $117.00. It appears that this is a seldom needed item because they only had 5 at the Chicago distribution center. I plan to dive under the boat to check the seawater intake to make sure it isn't partially plugged but the water is quite cold at this time. Any input would be appreciated.
Bob
 
Bob,
These are the same temps I see when running Karma. I would think we are okay.
 
I'm surprised at those operating temperatures. I'm used to seeing 175 degrees F with temp going up to 180 to 190 degrees when running at 85 to 95% of max rpm under load.

I must admit my experience is limited to about a half dozen older Yanmars. I've seen those kinds of temps with high performance motorcycles and cars.

I'd give Andrew a call. You might also check the temp with a remote temp gun; Radio Shack sells them, or they did.

Gene
 
Gene,
I have done both of what you suggest. I have been told that these temps are normal.
 
Hi Guys and Gals,
As you had suggested I talked to Andrew shortly after my overheat problem and he thought it might be a bit high. Last week I talked with MER Equipment about the temperatures and they felt it to be the "very high end" of normal; I would prefer to be middle normal. I am just trying to get some samples of op temps from a few sources. It is possible I do not have a problem but I prefer to be cautious. When I am running at higher RPMs I tend to slow it down at about 212' rather than see how high it will go.
Thanks for the inputs,
Bob
 
Bob and all,

Basic Thermodynamics - you have a bigger engine block so it needs to dissipate more heat. Your water coolant will in turn show a higher reading. It is possible you have some partial clogging in the strainer but you should only see it decrease a few degrees on your thermostat. If you thermostat failed you should either see no increase in temperature or a spike in the temperature at the low rpm readings. The spike you witnessed seemed to be driven by the impeller as you state.

Agree with what all were saying - these slight increases seem to be on par with a larger engine block.

Good luck and it sounds like you did all the right things.

Regards,
Rich
 
Bob:

I operate at about 208 WOT and 203-204 at half throttle. About 199 at idle.

Lyman
 
We run the same as Zuma

Stuart... Spirit of Gratitude
 
Most normal duty water cooled engines run best between 180 to 195 degrees regardless if they are gas or diesel. Close to boiling point but with a safe margin for engine load to increase the coolant temperature under heavy load. Most thermostats are a mechanical device that are designed to react at a specific temperature. The easiest way to verify your thermostat temperature is to first check the manufacturers rating, then remove the thermostat housing (usually two bolts) and check the temperature rating stamped on the thermostat. Obviously it should match the manufacturers rating. You can then check to see if it opens at the rated temperature by boiling it in water on your stove with your wife's candy thermometer in the pot with it. You will see it open within a degree of the rated temperature. Whatever temperature the thermostat opens at on your stove should be the normal operating temperature of your engine, give or take a degree. The thermostat should open and close to respond to increased heat hence giving the engine a reserve cooling capacity. If the engine runs hotter than the thermostat rating and the thermostat works properly I would look for a kinked cooling hose or a blockage restricting water flow.

Hope this helps, Leon
 
The "new" common rail diesels like the 6BY2-260 run hotter than the "old" diesels. I have checked with a number of trusted diesel mechanics and I think you are fine. My concern was the same as yours and I accept that this is in the normal range for this motor.

Happy Boating!
Denny
 
Folks, both Leon and the others are correct in what they say about operating temp of these newer engines and engines in general (including gasoline, turbojet, ramjet, rockets, etc). There are sweet spots for temp and then there is a margin where one can safely push a little.

What needs to be recognized is that power is a byword in selling, along with reliability. Those higher operating temps are the result of striving to produce higher power output within the parameters of the engine design, fuel availability, etc. I try to exactly follow the engine manfacturer's manual on engine operation. If they've miscalculated, then a warranty claim has validity. 😉 And, they do miscalculate. 🙁

Gene
 
I would like to thank all of you who have responded. I have had many diesels in my life, three in Ford vans and one in our 40' Monk, and this is the highest temp I have ever seen for normal operation ( the higher rpm running). I will continue to pay close attention and let you know if there are any issues. Leon, I want to thank you for the suggesation of putting the thermostat in boiling water to see if it opens up at a given temp but it is an assembly not the typical part that we are used to ( It was described to me I have not taken mine out to look at). I am still leary to let it rise in temp at higher speeds, but , maybe I will venture at some time and see how high it goes. The temp gage could also be defective.
Thanks Again,
Bob
 
Part of the commissioning sea trial is a full throttle run for a given time period... If it were overheating I would expect Andrew to have noticed...
 
Bob, I'm late to the discussion but something you said in the very first post caught my attention.

I had the fresh water impeller replaced (which had been quite damaged) and also refilled the antifreeze.

If this was damaged to the point of putting rubber pieces in the fresh water system, could it have partially clogged up a heat exchanger? If so, maybe it'll gradually work it self out.

charlie
 
Dennie-O,
The overheat I believe was a result of some recent event. The boat is a year old tomorrow and I am sure the condition did not exist at the time of sea trials or Andrew would have caught it. I have a great deal of respect for and trust in Andrew.
Bob

Charlie,
The impeller did not loose any blades or material that was obvious. The blades were cracked at the base which allowed them to bend back when rotating but not come apart.

Thanks to you for your input and I will continue to report any occurances that happen on the Nellie Too as a heads-up for the rest of you. The boat is great as built and I would not change a thing.

Bob
 
Just a shot in the dark here but, sometimes the impeller that will fit the application will have variations from the original depending on who makes it. Things like different number of vanes, or a thicker hub (shorter vanes), this can change the volume of water the pump will move. I had this occur several years ago when I had the impeller changed by a boatyard on a 15hp yanmar in an 30 ft S2 sailboat. The engine ran hotter until I changed the impeller myself (again) for one with longer and fewer vanes..solved the problem (the boat was 12 years old when I bought it so I never did find out which impeller was the "stock"size).
 
Does the engine operating manual, or the website, give operating temp range in the specifications? 🙂

Gene
 
Slackwater Jack,
What you are say makes sense but the part I got was a Yanmar factory part. I may however try to change it again as I have two spares now but its not easy to get to. Thanks for the input.
Bob

Gene,
I could not find it in the ops manual and it took the local distributer a while to find it for me. Thanks for all the good help.
Bob
 
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