Caballo Loco No. 4—a blend of vintages spanning 1992 to 1997 and bottled in 1998—builds upon the No. 3 edition by incorporating the 1997 vintage, which is recognized as one of the best of the 1990s and considered a historic benchmark for this wine. Syrah was added to the blend, which now comprises Cabernet Sauvignon, Malbec, Merlot, Cabernet Franc, Syrah, and Pinot Noir, sourced from vineyards in Colchagua, Curicó, and Maule (Central Valley Denomination of Origin). It features a reddish-orange brick color and 14% alcohol content. Aged for 24 months in French and American oak barrels; 36,000 bottles produced.

It is situated in a horseshoe-shaped formation facing the Mataquito River within the Coastal Range, with a northerly aspect, and is protected from the cold coastal breezes that flow up and down the river. The soils are of granitic origin, derived from colluvial deposits from the surrounding hills. It features Pinot Noir vineyards (planted in 1968) using the Valdivieso clone, characterized by very low yields.