I am cleaning up a Bird Termaline 8890 in preparation for working on my GPT 10K and I realize it most likely needs some oil.

I reach out to Bird and ask for  a modern equivalent to the part # indicated in the manual

They cheerfully send me to a link ( Bird RPK8890-3, Coolant Kit | Bird RF Online Store (btgstore.com) )  for the oil.

The kit only costs $1300 for 3 gallons of oil - and a gasket.

I couldn't believe it. 

Anyone have any advice about a lower cost replacement for the oil ?

I was thinking of using the MFJ transformer oil for loads.

tnx

de WA4AM

Mark