# Tube Between Radiator and Expansion Tank Blows Off



## jfull550 (4 mo ago)

Tractor Yanmar 2310D

Lately, everytime I run the tractor the tube between the radiator and expansion tank blows off at the expansion tank. I haven't hose clamps on the tubing yet because none were needed in the past. Any insights as to why this is happening?

Jim


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## bmaverick (Feb 20, 2014)

jfull550 said:


> Tractor Yanmar 2310D
> 
> Lately, every time I run the tractor the tube between the radiator and expansion tank blows off at the expansion tank. I haven't hose clamps on the tubing yet because none were needed in the past. Any insights as to why this is happening?
> 
> Jim


When was the last time the cooling system was flushed?

Hoping the coolant used is _NOT_ the Long Life type. This would cause some issues. 

IF the machine was worked hard in hot 90F+ temps for a long period weepage of pressure 'could' be possible from the head gasket.

Another item to consider, if the engine oil is 15W40, heat remains trapped longer in the engine and/or heat is not dispersed quickly, then the cooling system has to work harder and the pressure increases. These Yanmar's are built to JIS standards and not SAE. Thus, 10W30 summer and 5W30 winter is required. 

Lastly, the air intake filer, when clogging, will make the engine work harder as the stroke on a diesel is longer. Cleaning the air intake filter can and will lower the engine and cooling temps and the pressure will return back to normal. 

Bret


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## 2billt (Aug 7, 2011)

@bmaverick is the gold standard for troubleshooting Yanmars.

I'll throw out a couple of possibilities but determining if your operating temp has increased should be conformation #1

Other basic "overheat" concerns could be...
1. Radiator cap, pressure relief defective? (7 or12 lb?)
2. Fan belt tension
3. Thermostat, of course

If excessive heat is not the problem.....
A. Over-flow tube expanded/ loose or tired, at connection (cut back or replace)
B. Drop tube, inside expansion tank obstruction?


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## bmaverick (Feb 20, 2014)

jfull550 said:


> Tractor Yanmar 2310D
> 
> Lately, everytime I run the tractor the tube between the radiator and expansion tank blows off at the expansion tank. I haven't hose clamps on the tubing yet because none were needed in the past. Any insights as to why this is happening?
> 
> Jim


Jim, 

You are looking at something like this below. Where the two red arrows show the wimpy clamps, the over-flow bottle has a rubber seal cap and the coolant should be filled in the area of the green lines. This YM2610 right now is listed on PurpleWave. I would not buy it. No coolant in the over-flow 'could' mean a blown head gasket! 

There is no relief of pressure in the over-flow bottle.


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## FredM (Nov 18, 2015)

jfull550 said:


> Tractor Yanmar 2310D
> 
> Lately, everytime I run the tractor the tube between the radiator and expansion tank blows off at the expansion tank. I haven't hose clamps on the tubing yet because none were needed in the past. Any insights as to why this is happening?
> 
> Jim


I'd be checking the breather hole in the expansion tank cap, needs this for expansion and contraction of the coolant.


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## John Liebermann (Sep 17, 2018)

FredM said:


> I'd be checking the breather hole in the expansion tank cap, needs this for expansion and contraction of the coolant.


Expansion tank should not be pressurized.


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## FredM (Nov 18, 2015)

John Liebermann said:


> Expansion tank should not be pressurized.


Read the quote again, nowhere did I say the expansion tank is pressurised, the breather hole in the cap is needed for when the fluid in the radiator gets to operating temperature and expands and lifts the cap valve off of the seat to allow the fluid to enter the expansion tank and likewise when the radiator coolant cools and creates a vacuum and pulls back the fluid from the expansion tank.

The fact that the hose is blowing off the tank spigot shows that either the hose end is stretched or the cap has a plugged breather hole.


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## John Liebermann (Sep 17, 2018)

"radiator and expansion tank blows off" And that means it was/is pressurwized. If the hose just falls off that should be obvious by observing the hose end. 

Even if you did not induce pressure yourself being pressureized is still an issue.


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