The impurity contribution to the spin‐lattice relaxation of the Al27nuclei has been studied in the compoundsLa0.99Ce0.01Al2andLa0.95Tm0.05Al2. The impurity component of the magnetization recovery is observed to be non‐exponential, which is attributed to diffusionless relaxation of the nuclei to the magnetic impurities. An analysis of the functional dependence of the resulting rate, 1/&tgr;1, indicates that longitudinal fluctuations of the dipolar field are the principal relaxation mechanism. An analysis in the RKKY approximation indicates the strength of the impurity‐conduction electron coupling in the Ce and Tm cases respectively is 2.5 and 1.7 times that forLaAl2Gd.