Operating without a thermostat?

[etpm]

Last weekend I flushed the cooling system and filled it with new coolant. I noticed that coolant is flowing in the radiator as soon as the engine is started. And the temp gauge always shows the engine running cool. So I think the thermostat is missing or stuck open. The tractor seems to run perfectly but since this is my first diesel engine powered anything I don't know if running cool could be damaging anything. I would rather not try to replace the thermostat if I don't need to. If I do does anybody know which thermostat it takes? Or if it is a common one that I can just take to the auto parts store and have them match it? I know I can buy one from Hoye or Fredricks but their prices and shipping charges are ridiculous. Hoye wants 40 bucks for a thermostat and Fredricks wants 23 bucks. Those prices seem high. Hoye wants 17 bucks shipping as does Fredricks.
Thanks,
Eric

 

[winston1]

Amazon.com

 

[careyo63]

Yanmar 2310 are comon. Org. # 129350-49800 Thermostat.

Thermostat 129350-49800 for Yanmar YM2002 YM140 YM146 YM1802 YM2620 YM2010 YM2310

Thermostat 129350-49800 for Yanmar YM2002 YM140 YM146 YM1802 YM2620 YM2010 YM2310

www.fridayparts.com

Free Shipping Cheap!
Still have that PTO.Shaft LOL...... Still can't Weld!!

 

[California]

Yanmar used a lot of third-party common stuff like thermostat, alternator, oil pressure sender etc that also appeared on Datsun (Nissan) in the same era. So a generic thermostat for an 80's Japanese car at the same rated opening temperature should be fine. rScotty, is this ok?

I'll also note my YM240 (YM2000), designed a few years earlier than YM2310, doesn't have a thermostat (or temperature gauge). Only a boilover warning light. Simple, and sufficient.

 

[careyo63]

I tried NAPA and nothing!

datsun therrmostat 129350-49800 for sale | eBay

Get the best deals for datsun therrmostat 129350-49800 at eBay.com. We have a great online selection at the lowest prices with Fast & Free shipping on many items!

www.ebay.com

 

[etpm]

Amazon.com

Thank You, I'm gonna order one.
Eric

 

[etpm]

Thanks for all the quick replies folks! I love TBN!
Eric

 

[ruffdog]

A diesel runs best the sooner it can get to full operating temperature. A car/truck with a stuck open thermostat will have horrible fuel mileage in a cool climate.

 

[etpm]

A diesel runs best the sooner it can get to full operating temperature. A car/truck with a stuck open thermostat will have horrible fuel mileage in a cool climate.

Thanks for the reply. It seems like it would be a very good idea to have a working thermostat. I'm ordering one tonight.
Eric

 

[ROUSTABOUT]

It needs a thermostat.

 

[careyo63]

Esp. if it's cold out! Your find the Heater works!! Or doesn't!!...JS.

 

[irq]

Do you guys know what thermostat will fit to Yanmar FX24D tractor? Or where to check it?
I've unscrewed the hose where a thermostat is placed and measured the diameter (44 mm) and depth (43 mm).
But what's left to check is opening temperature the thermostat should have. Is it 71C (160F) or 84C (183F)?. Does it matter much?
Of course I was searching the net, but there's no consistent knowledge about it.
Photos

 

[careyo63]

I'm showing HT-9155 Thermostat F-18,195,215,255. Then FX26,22,42,195,215,255,285,305
No FX24-?
Thermostat HT-9150 F17,F,20,F22,F24.
My books parts is old. Why no FX-24 ? this is Fredricks so I'm sure they know which one or both may fit for that matter.

 

[ponytug]

@irq I don't think it matters much. I would try to buy the higher temperature thermostat if you use your tractor at all during the colder months.

Good luck! (And welcome to TBN!)

All the best,

Peter

 

[bmaverick]

Do you guys know what thermostat will fit to Yanmar FX24D tractor? Or where to check it?
I've unscrewed the hose where a thermostat is placed and measured the diameter (44 mm) and depth (43 mm).
But what's left to check is opening temperature the thermostat should have. Is it 71C (160F) or 84C (183F)?. Does it matter much?
Of course I was searching the net, but there's no consistent knowledge about it.
Photos
View attachment 872769 View attachment 872772

84C (183F) is correct.

 

[rScotty]

Temperature is important for little diesels. The engines don't have a lot of mass, so temperatures and therefore the internal clearances do vary a lot. You want to keep them as constant as you can.
Many Yanmars are sleeve-bore, and they all have a high flow coolant system without a special bypass path like is common on big diesels.

Switching to a guage that reads out in degrees of temperature is sure worth doing. I liked to see my engines in the 180/190 F range. But not uncommon to see it from 170 to 200 - or more - depending on the work it is doing. With a gauge in degrees you can know for sure. Some winters I do block off part of the air flow past the radiator to keep the temperature up. Motors are real individualistic that way. I suspect air flow past or around the sides of the radiator is a lot of the reason. Clean the screen often.

If a thermostat fits and has clearance enough to open it will work. You can test the thermostat using a candy thermometer in a pan of hot water on the stove. Some have a smallish bypass hole in the mountng plate.
Thermostat failures are rare, but they are not precision devices. The percent opening & flow resistance can vary over a 5 to 10 degree range on some. Let us know what you find out about yours.

Don't be afraid to massage the cooling system to make it run at a good temperature.
Use 50/50 ethylene glycol/water
Luck,
rScotty

 

[careyo63]

In Ga. I only run 35% antifreeze be careful Walmart etc. offers it prediluted 50/50.
I can say looking into it Thermostat HT-9350 is 160Deg. Ym2002 etc. uses it.

 

[ponytug]

In Ga. I only run 35% antifreeze be careful Walmart etc. offers it prediluted 50/50.
I can say looking into it Thermostat HT-9350 is 160Deg. Ym2002 etc. uses it.

Yes, I'm glad that works for you, but the poster (@irq) is in a rather colder location (Cracow), where 50/50 glycol water is definitely necessary, based on the winter temperatures...

All the best,

Peter

 

[irq]

Thanks guys for your replies. I will consider all your advices. As of now I bought the thermostat, which fits the following Yanmar engines: 4TNE88 3TNE88 3TNE84 4TNE84 4TNA78 3TNE78 3TNE68. It opens by 82 C (180 F).
My engine number is 3TNB84-UA and I couldn't find the thermostat exactly for it (by number), so I took a chance nad choose the most similar (by look) engine 3TNE84 and bought available for it thermostat. Of course, I know that looking for a missing part based on the appearance of the engine is not necessarily a good idea, but the diameter (44mm) and opening temperature (82C) are right.

As a coolant I pour the same pink fluid I use for my cars. Here's its specs:

 

[ponytug]

With these older engines and the changing coolants available, I think it is hard to know what the best coolant is sometimes.

Good luck!

All the best,

Peter