Recommended Replacement Coolant for Bird Part #5030 - GE Type 10C Transil Dielectric Oil?


If you're using one of our older Termaline model loads like the 81, 6835, 8221, 8833, 8834, or any other models that are now classified as "Discontinued Products," you might be wondering about maintenance. Although these models are considered obsolete and finding repair parts might be difficult, performing regular maintenance can extend their lifespan. One important maintenance step is checking or replacing the coolant, which may be referred to in the manual as "GE Type 10C Trasil Dielectric Oil, Bird part #5030." Unfortunately, we no longer supply this specific coolant, but we do have an alternative available.


Over time, we've updated our coolant from the #10 C in the 1950s to Texaco 600 #55 transformer oil, and most recently to Shell “Diala” S2 ZX-A. Our latest coolant is the 5-030 mineral oil, which you can find in our Bird Online Store. Please note: While using the new coolant may result in slight differences in your VSWR, it should not significantly affect operation.


Do NOT mix or top off with new coolant. Avoid combining the old coolant (#5030) with the new 5-030 coolant. If you need to add more coolant, do not simply add the new type on top of the old; instead, fully replace the old coolant with the new 5-030.


To date, we provide three different volume purchasing options directly through our Bird Online Store.

  1. 1/2 gal. (5-030-2)
  2. 1 gal. (5-030-3)
  3. 5 gal. (5-030-4)


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