3YM30 Coolant Service

[hxschiller]

There are two drain devices on the Yanmar 3YM30 to drain old coolant. The one that's on the starboard side of the engine block and seems to be somewhat obvious; simply unscrew a bolt. However, the other one is on the port side of the engine in the middle of a (very circuitous) coolant hose in what appears to be a rubber TEE fitting. Just how does one drain coolant through this thing? Is there a special tool? Must I remove the clamp on the TEE?

 

[nzfisher]

Is this the Yanmar 4by engine? If so most people that DIY just drain from the side with the finger drain, refill and call it good and hope for the best. Make sure to use the proper coolant

 

[SGIDAVE]

There are two drain devices on the Yanmar 3YM30 to drain old coolant. The one that's on the starboard side of the engine block and seems to be somewhat obvious; simply unscrew a bolt. However, the other one is on the port side of the engine in the middle of a (very circuitous) coolant hose in what appears to be a rubber TEE fitting. Just how does one drain coolant through this thing? Is there a special tool? Must I remove the clamp on the TEE?

Hello hxschiller,

I believe you use an Allen wrench to remove the 'plug' in that drain.

/dave

 

[SGIDAVE]

Is this the Yanmar 4by engine? If so most people that DIY just drain from the side with the finger drain, refill and call it good and hope for the best. Make sure to use the proper coolant

Hello NZ,

He is referring to the 21EC engine, Yanmar 3YM30 (3 cylinder, 30 hp diesel)

/david

 

[hxschiller]

Thank You Dave! I found by process of experimentation, that the thing unscrews from the bottom with a 3 mm Allen wrench/hex key. Tugnuts fora came through again.

 

[SGIDAVE]

Thank You Dave! I found by process of experimentation, that the thing unscrews from the bottom with a 3 mm Allen wrench/hex key. Tugnuts fora came through again.

Can you give an estimate of HOW MUCH coolant actually drained out?

/dave