[5rebel9]

Looks to me that the thermostat housing has sprung a leak. They were redesigned to correct this problem. The heater hoses were changed also with the new part for the early(your) Avengers. YES it is serious if you keep driving as the motor is loosing its coolant and introducing air inside, not good for driving . The res. may still have coolant in it, but take the rad. cap off and I bet you will not see much if any coolant there.

Edit: REALLY 117 yrs old?

 

[5rebel9]

Depends on the skills of a friend, not hard to do but with proper "bleeding" of the coolant system when done should take no longer than 2 hours to complete. There are threads on this page of members having done this chore themselves.

 

[5rebel9]

The part, if dealer bought should include all the pieces needed due to the updated(revised) part.

 

[5rebel9]

Yup! I kind "jumped the gun", I surmised that that may have already been done. One never knows for sure when communicating by print.

 

[5rebel9]

Should be a pretty straight forward R&R, Make sure you let the air bleed out of the cooling system by leaving the rad cap off while idling the motor, you may have some coolant bubble out but put the cap on and shut down and let it cool down then finish refilling thru the rad. cap. When all air is purged and the main system is full, then top up the res. as needed.

 

[5rebel9]

YES. Make sure the mating surface of the motor is nice and smooth (clean) before installing the new unit.