Haven't ever bought one, but we deal with them all the time at the shop. Some are real finicky on what they will actually pay for, and some pay for everything, no questions asked.
Some of the extended/used car warranty companies will pay for a repair, IF their adjuster believes the damage is not "normal wear/tear", BUT they won't pay for fluids!
My only advice would be to read
carefully any contract you may be considering, and make sure it will actually cover everything you are concerned with.
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Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"