Grease Turning to Liquid in Grease Gun

[curado100d]

I have successfully used Pennzoil 707L red grease in my trailer bearings for years. I always keep a grease gun in the truck bed (which has a tonneau cover). Since moving to Florida, the high heat under the tonneau cover is causing the grease to turn to liquid and run out of the grease gun. I called Pennzoil and inquired about their "Marine grease" but was told by a technician that it would liquidfy also.

Are there greases available that won't turn to liquid? What about synthetic marine greases? I'm not sure how hot it gets under that tonneau cover in the Florida sun, maybe 125 - 135 degrees ?

[TRCM]

It'll get hotter than that under there.

not much you can do, 'cept not keep the grease under there.

Mine even does it in the garage, and I know it ain't that hot in there