Wheezer

[f. WHEEZE v. + -ER¹.] One who wheezes; esp. a broken-winded horse.

1831.  Youatt, Horse, x. 196. The Wheezer utters a sound not unlike that of an asthmatic person when a little hurried.

1844.  H. Stephens, Bk. Farm, II. 227.

  transf.  1915.  Blackw. Mag., Aug., 259/1. Beastly cold on top of this old wheezer [sc. omnibus].