Water flowing out of expansion bottle

[EuroYanmar]

I am sure somebody on the board can give me explanation of this phenomenon :

When the engine of my Yanmar AF 22 runs 10 minutes, water level in the expansion bottle begins to increase slowly. After 5 more minutes water begins to flow out of it.

The water in the radiator is clean with no trace of oil in it.
The engine is running normally, no white or black smoke from the exhaust.

In the same time and in a strange way the temperature indicator stays on "cold" (not an basic red light but a normal indicator with a needle indicating the temperature from "cold" to "warm").

My questions are :
1) What is your diagnostic ?
2) How to test such a temperature indicator (it's not a red light) ?
3) Could this problem be originated in the thermostat or is it a more serious problem ?

Any help will be appreciated

Phil

 

[Soundguy]

I'm not sure what range your temp gauge reads to/from.. but if you think it is suspect.. drop the bulb in a pot of water and start boiling it. Add a candy or other cooking thermometer to the pot for a reference temp, and see what your gauge reads in comparison to the thermometer.

With the engine cool, open the radiator and start the tractor.. are you getting any bubbles in the radiator neck? If so.. it's a compression leak.

Soundguy

 

[EuroYanmar]

Soundguy,

Thank you for your advice about how to check temperature probe. I will try as soon as possible.

The compression leak you mentioned could it be only originated in a bad head gasket or it could be a cracked head or block too ?

I noticed too a strange rusty mud in the expanding bottle.

One more question : Is there any tip to check if a head gasket is deficient without opening the head ?

Thank you very much for your answer,

Phil

 

[normde2001]

"I noticed too a strange rusty mud in the expanding bottle."

That, and possibly a bad gauge could very well be your problem.

 

[ducksjunk]

I always work with the KISS method.
Check the simple things first.
1] Are you filling the overflow bottle too full to start with. When cold it should be at minimum level. this allows for the expansion when the engine warms up.
2] Check or replace the rad cap. If the rad cap is not working at the right pressure or is damaged it will allow coolant out before it should. It may also not allow for recovery of the coolant to the rad which will just cause it to keep putting coolant into the bottle without drawing it back in. A crack in the hose to the recovery bottle will also do this.
Lots of simple stuff to check before you condemn the head.
good luck.
The rusty coolant may just be the result of using straight water, or poor maintenance or both.
Richard.

 

[Soundguy]

Euroyanmar..

Bubbles in water.. water in oil, oil in water are all signs of a bad head gasket ( or bad head.. or bad block! )

Also.. flush the system.. that orange gunk adds ions to the water just like antifreeze.. ( but not like anti-boil). it greatly effects heat transfer and circulation on a non-pump system.. You could have local hot spots and even be boiling the water.. etc.

Flush and re-check with clean water.

Soundguy

 

[EuroYanmar]

Richard,

Thank you very much for your answer.
As I see there are some very simple things to check : radiator cap, looking for cracks in the hose to the recovery bottle. I will check them soon.

Thanks, I really appreciate,

Phil

 

[EuroYanmar]

Sounguy,

Thank you for this new advice. You are right, I must flush the system and recheck. (AF 22 is with water pump and 3TNS82RA engine). I will post pictures on the board very soon.

Phil

 

[kayssupply]

I would really like to see some pictures also. That is probably the newest Grey Yanmar I have heard of to date.

 

[EuroYanmar]

As it could be useful for friends on the board I post here the final explanation of the above phenomenon

I took out the head of the engine and the metallic head gasket looked in good condition. I sent the head to a specialized shop, they checked it and saw it was like new BUT VERY RUSTY. They told me rust has an incredible power : the chemical reaction creating rust can produce a strength that can push a head even if it is bolted to its maximum torque.

I changed the head gasket, put back the head and ....everything became normal (no more air leak in the radiator). Strangely, the temperature indicator stayed on "cold". I changed the thermostat with its John Deere equivalent and the indicator now works perfectly.

I hope these information can help some friends in the future.

Thank you one more time for all your advises.

Phil