Are you sure you don't mean 4.g4!? in the Advanced Caro?
The Caro-Kann Advance

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This is why I play 3...c5!? in the Advance, to avoid all of this. Or at least I think it gets an interesting nowadays. I've had pretty good results with it, though! Mostly wins, a few draws, a handful of losses.
Hey guys,
I am new to this site but a frequent chess player. I am looking for a weapon against the Caro-Kann and I recently found an interesting idea in the Advance line.
1.e4 c6 2. d4 d5 3. e5 Bf5 4. h4!? with a very clear plan for White. Probably not the soundest of ideas, but I like it better than the Fantasy variation of the Caro-Kann.
Are there frequent replies to 3. e5 from Black? How should White continue? I am currently attempting to salvage a worse, but drawish position as White after 3 ... c5!?.