425 COOLANT FLUSH & REPLENISHMENT

[sriddle1]

Fun times in New Hampshire this morning......The lower bolt to the Thermostat Housing sheered while I was cutting the lawn and coolant started leaking......After removing the Housing I was able to remove what was left of the bolt (thank Goodness). I ordered a new T-STAT, Gasket and the two bolts, coming-in tomorrow. I thought I'd flush the coolant once I get it back together, I've read there are flush kits, not sure about the 425 though? I have the JD Service Manual on CD but can't find any procedure outlining a flush/replenishment. Any help appreciated...

 

[beenthere]

Some may flush with a cleaner, but I'd just run straight water through the radiator, then fill it and run the tractor for a short while. Then drain and replace with coolant and expect to be "good to go".

Scary that a lower bolt would shear off.. but I was surprised that that bolt had some corrosion when I tore down my 425 Kawasaki engine earlier this year.

I was further surprised by the low torque specs for the water pump bolts.

 

[sriddle1]

Thanks for your response, I've read some blogs and see water is the preferred method.... I didn't see an air bleed on this Kawasaki Engine, air certainly is in the block after removal of the T-Stat... :reading:

 

[beenthere]

I didn't see an air bleed on this Kawasaki Engine, air certainly is in the block after removal of the T-Stat.

Never thought of air being a problem with coolant.

 

[Richard001]

Never thought of air being a problem with coolant.

Most likely there will be some air trapped in areas. Typically this will work it's way out after running the engine for a few minutes. You want to make sure you have all the air out of the system before you put the unit to work.

Richard

 

[beenthere]

I'm curious to how one would know they were sure to have all the air out of the system. just curious.....

 

[Richard001]

I'm curious to how one would know they were sure to have all the air out of the system. just curious.....

Just like you would with an auto engine. Fill with coolant, leave the radiator cap off, run engine at fast idle and watch the coolant level in the radiator. Also important to fill the reservoir about half full if it has one.

After a few minutes, shut the engine off and check the coolant level in the radiator. If down any, refill and do again. Repeat as necessary to the point when you can not add coolant. Put the radiator cap back on and your good to go.

Richard