Green Yanmar Problem

[tacticalturnip]

Replace the radiator cap. The vent is plugged or the deflection disc will not spring back.

You're a treasure in this community- coming here with simple solutions and the knowledge to back it up!

 

[R Barger]

Replace the radiator cap. The vent is plugged or the deflection disc will not spring back.

I have replaced the radiator cap with a new one and also tried a couple of others including a vented 15lb one.

 

[R Barger]

Make sure the overflow vent is clear. If it isn't, air can't come back in and let the coolant return. I'm a little confused by the statement that there is pressure on the system after shutting down. If there is pressure in the cooling system after it cools off, that would keep the coolant from returning. It should go negative after shut down.

The overflow is clear. That is the first thing I checked. I can't check it 2 days after running it and there will be slight pressure in the system. That's what is why I thought the system does not have a leak.

 

[careyo63]

Remaining pressure days later sounds like a dirty clogged up radiator. Air pressure pockets is what I call it. Running should be around 13-15 PSI.. A big chain Auto parts store will rent or lend a test kit to check it.

 

[R Barger]

Remaining pressure days later sounds like a dirty clogged up radiator. Air pressure pockets is what I call it. Running should be around 13-15 PSI.. A big chain Auto parts store will rent or lend a test kit to check it.

My thought is maybe part of the radiator is clogged causing a little more than normal pressure when running at 2000 rpm for a length of time. Coolant not leaving the bottom as fast as the pump is putting it in. I am going to back flush the radiator today if that don't change things I'm going to go ahead with the head gasket replacement.

 

[ponytug]

My thought is maybe part of the radiator is clogged causing a little more than normal pressure when running at 2000 rpm for a length of time. Coolant not leaving the bottom as fast as the pump is putting it in. I am going to back flush the radiator today if that don't change things I'm going to go ahead with the head gasket replacement.

Have you tried looking in with a bright light or borescope to see if you see signs of gunk or corrosion?

All the best,

Peter

 

[KWentling]

Kind of a long shot here but I have seen the inner lining of hoses come loose and act like a check valve. You might check the hose between the expansion tank and the radiator neck.

 

[R Barger]

Kind of a long shot here but I have seen the inner lining of hoses come loose and act like a check valve. You might check the hose between the expansion tank and the radiator neck.

The hose is a single ply hose with no problems.

Today I removed the thermostat flushed the engine and back flushed the radiator. Everything is very clean. At 2000 rpm with the cap off the the water passes through the radiator with no restrictions. The thing that surprised me was I put the radiator cap on and rode the tractor at 2000 rpm for 15 min. and it put no water in the expansion tank. The was cool enough that I could put my bare hand on it. Every time I decide to do the head gasket, I start having second thoughts.

 

[ponytug]

The hose is a single ply hose with no problems.

Today I removed the thermostat flushed the engine and back flushed the radiator. Everything is very clean. At 2000 rpm with the cap off the the water passes through the radiator with no restrictions. The thing that surprised me was I put the radiator cap on and rode the tractor at 2000 rpm for 15 min. and it put no water in the expansion tank. The was cool enough that I could put my bare hand on it. Every time I decide to do the head gasket, I start having second thoughts.

Diesels are much more efficient than gasoline engines, as they are fuel limited. A fair amount of the non-work heat losses are passed through the exhaust due to lean mixtures burnt in a diesel engine.

That said, my apologies, I am still trying to understand your problem. The engine isn't overheating, it runs, and it leaves some coolant in the reservoir. That sounds like normal operation from this armchair. What am I missing?

All the best,

Peter

 

[kennyd]

LOL, here's what I thought from the thread title: