Reduced engine heat to hot water heater & Kubota dealers in CA

[Stu Jackson]

Update:  replaced the thermostat with the 82C (180F), now the engine runs at 180 to 185 instead of 160F with the old thermostat.  Haven't had a chance to check out the hot water from the engine since we were plugged in between races at the Nationals.  Only will know the next time we use the boat.  Will keep U posted.

[Ron Hill]

Stu : Regarding the National Races: With a +20 degree higher thermostat, Aquavite must be some kind of "HOT" boat when motoring!!  What about when sailing??    :rollingl

[Footloose]

Acually, I would be interested to know how long it takes to get hot water with the new thermostat.  Footloose lives on a mooring so we are always starting from cold. 

[Mike and Joanne Stimmler]

Stu, why did you go to a 180 degree thermastat from a 160? Seems way too hottttt!

Mike   

[Stu Jackson]

Thanks, Ron, it's somewhat hot when sailing, too.     Only occasionally, though.

Mike, I went to the 180 F thermostat because I wasn't bright enough to simply request the 160 F thermostat.  I ended up selling my second thermostat to another C34 owner who needed one at the docks during the National Regatta, so when I get a chance this week I'll call the Kubota dealer and order two new 160 F thermostats. The Kubota catalog numbers for the thermostats was recorded in the earlier posts I referenced, but when I get them I'll note them here, too.

The engine temperature runs between 180 and 185 degrees, the gage swings a bit within that 5 degree band.  180 is not too hot to run a diesel.

Dave, The hot water is now working, although it seems to take a somewhat longer time to heat the water.  Perhaps I was too impatient.  It takes about 45 minutes of motoring.  I noticed that the water in the heater gets hotter even after you turn off the engine, so the heating coil stays hot for a while and keeps heating the water.  The engine has to be run at cruising speed, running it anchor at 1500 rpm for charging, for instance, just won't get the water hot within any reasonable time.

Accordingly, I'm going to replace the hoses from the thermostat housing to the water heater, since the water heater was new when we bought the boat in 1998 -- it is not OEM from 1986.

Added May 2008 - Here's why!!!:  http://c34.org/bbs/index.php/topic,3769.0.html

[David Sanner]

Stu... as others have suggested it sounds like you've got a flow issue, probably in the HW loop but
maybe restricted flow somewhere else in the system.  Or maybe it's all in your mind ;)
(45 mins...  I think my water heats up much sooner)


I installed Stu's 180 degree thermostat and my engine is running steady at 180 degrees.
The thermostat that it replaced was a 160 degree thermostat that was less than a year
old. Unfortunately it seemed to have the same problem as the one it replaced which caused
the engine to run in the 140 range.... or less.  ie. stuck open.

The manuals mentions 180 degree operating temperature.  I would think the
engine would be more efficient running at 180 than 160, less carbon, etc.  Or not?



-d

[Ron Hill]

Stu : I'm glad that you're going back to a 160 degree thermostat, even though diesels are said to run better hot.  I'm sure that the engineers selected 160 rather 180 for that reason of being too hot.

Guys : I've talked you a number of people over the past 20 years with M25 series engines and it takes about 1 hour of motoring to get hot water!! After all you're trying to warm up 6 gallons of water, not just a few quarts.  The warm coolant is also going thru the heat exchanger to help keep it from heating and the water heater is only a secondary by product !!  After all the engine will run at 160 without a waterheater!!!  

[Stu Jackson]

Reference to Bernd's post on thermostat model numbers from Kubota: http://c34.org/bbs/index.php?topic=1067.0

It says:  

p/n15531-73010 (180 degree)
p/n19203-73010 (160 degree)
p/n1576-73270  gasket


New thermostat gasket model # is: http://c34.org/bbs/index.php/topic,4165.0.html

I just ordered two 160s.  The local Livermore tractor dealer had one in stock and is getting me the second.  Very helpful people in Livermore, Roy in parts.  For you Northern California guys who need tractor parts, I highly recommend Team Power (see post in this thread above for phone #).

[David Sanner]

Ron, you mention the designers chose 160 but I've been looking
over the manuals (http://www.c34.org/manuals/index.htm) and they all
seem to talk of 180 degree not 160.  ... normal operating temp 170-190. 

I guess there's a starting opening temp and a fully opening temp but the service
manual from the above link says the opening temp is 180F.

I'm not sure what the opening temp is on mine but it's stamped 82c (180F)
and the engine runs right in the middle of the gauge (on the big number) 180.

With my 3" heat exchanger and the colder waters of the San Francisco
bay I've only had the problem of the engine not running hot enough.
...except when my intake plugged up ;)

-d

[jmnpe]

One possible consideration of the 180 versus 160 degree callouts is that the "typical" application for the industrial version ( i.e. - tractor ) of this engine is in non-cowled or loosely cowled compartments with the radiator fan moving lots of air out of the minimal engine compartment. In the C34 application, we don't get nearly as much air moved out of the compartment, and at least down here in Texas summers that nice "cool" 104 degree intake air doesn't help moderate the temperature in the engine compartment very much.

Only speculation on my part.....

John

[Stu Jackson]

Received the 160 F thermostats yesterday:  $21.69 each.

The 180F s were "only" $16.72.

[Stu Jackson]

The hot water is back -- with a vengeance.  Took the boat out yesterday, looks like there may have simply been an air bubble in the hot water line to the heater.  Water's hot now, and gets there pretty quickly like before (about 40 minutes), and is hotter than before because of the 180F thermostat.  I'll switch back to the new 160F when I get a chance.  Thanks for all the ideas and suggestions.

[John Sheehan]

One possible reason for the 160 rather than the 180 in the marine applications is the lower temperature would reduce the amount of mineral precipitation in the heat exchanger.

[Jimlad]

Hi Stu,
Regarding the problem below, I've encountered the same issue but in reverse in that my failed thermo was a little larger than the 'new' one as supplied by the dealer when I updated my spare part inventory (part 301358).  I think my dealer needs to update his stock and ship the part no 200218 to me. My vessel is built in 2002 (This is a real bummer when you try to stock up on spares and the spares don't fit - I guess the moral of the story is, always check you have got the right spares, even to the extent of trying to fit them)

An update from my dealer.  Up until March 98 the M35B had a thermostat assembly that had a flange diameter of 38mm.  Engines manufactured after March 98 had a flange diameter of 44mm.  According to him the the later part number is 201001.  Thanks to Prince of Rivergare Marina up in Brisbane for the research and great customer service!

I agree, and thanks.  Next ?:

I purchased a new thermostat this afternoon.  The old T # (Universal) was 301358 (8 years old).  The new "kit" which includes the gasket, is a #200218, and the thermostat plastic bag has this # on it, so I don't think it was just a change in the product # to include the gasket.  The salesperson noted that Universal had changed the product # after checking on his computer.  The new T is a little wider in diameter at the flange and not as deep.

Anyone have any recent experience on this product # change and T size?  I have the puppy in my hot little hands and am prepared to put it in, just want to know if anyone's had this experience, and if you know if it fits.  I'm fully prepared to try it out (not a hard job, at any rate), but it'd be nice to know that it will fit in the hole!

[Stu Jackson]

and buy two or more when you do find them...