DF 140 need to flush head?

[Molarboater]

Thanks for all the previous posts that have helped to dx the 1-5 code issues. I removed the Exhaust Temp Sensor and saw a bit of white pasty corrosion in the hole. I think the sensor is OK but I need to flush this stuff.

What is the easiest way to clean this without dismantling or is that the only way to clean? I replaced the impeller 2 years ago & has a good flow in the lower.

[Molarboater]

Also, if I will need to pull the head, could the moderator give me a list of gaskets, etc I will need to order.

[Molarboater]

After researching on some other sites, seems 2003 & newer Zuks (mines 2002) use a surface mounted Exhaust Temp Sensor & is not subject to being exposed to corrosion inside the exhaust manifold which corrodes the sensor (bolt) & causes warnings.
Many state the fix is to leave the old bolt as it may break when removed and just disconnect. Then, plug in a new sensor and attach the end of the bolt touching the surface of the exhaust manifold as the newer models are designed.
Guess my question remains, what about the corrosion INSIDE the exhaust manifold? And how do you remove it, flush it etc?

[Molarboater]

Unplugged bolt and ran with water muffs on had strong flow out the ExhaustTemp Sensor hole, in fact, it idled much more smoother than it has since this sensor went off. Obviously there is water flowing well.

[Molarboater]

Put in the new sensor, just like the old sensor yesterday and all is well!
New sensor bolt has a bigger head and a rubber/plastic coating on the end to prevent corrosion and triggering a false Temp + 1-5 code.
So, which sensor will go out next?