I had that problem in my patrol.
I tried heat shields, venting, but unfortunately nothing seemed to work.
I usually got at least 3 years out of a deep cycle so under the extreme heat I wasn't too upset.
I don't believe there is any fix in a patrol.
Anyhow............
Great to see you are being pro-active with this.
Best wishes to a top swagger.
Cheers,
Brian
(Oh and I solved the problem by buying a prado

)