is supported within a stationary structure not indicated of the engine annular heat shields 48 50 are installed to cover the outer wall not indicated of the bearing housing 32 the heat shields 48 and 50 in combination with the outer wall of the bearing housing 32 define a space not indicated therebetween for insulating the bearing chamber from the combustor the stationary structure of the engine defines a plenum 42 surrounding the bearing assembly 30 the plenum 42 contains pressurized air which enters the bearing chamber 34 of the bearing housing 32 through the front side seal 36 and rear side seal 38 a diffuser heat shield 44 which is preferably an annular metal plate extends from the stationary structure of the engine radially and inwardly towards the bearing housing 32 an inner end of the annular diffuser shield 44 abuts an annular ridge 46 such that the diffuser shield 44 in combination with the ridge 46 of the bearing housing 32 forms a partition between the front and rear seals 36 38 of the bearing housing 32 referring to fig2 3 and 4 the ridge 46 includes an axially protruding rim portion 52 preferably having bevelled surfaces not indicated and a recessed portion 54 having a substantially radial annular surface 56 the inner end of the diffuser shield 44 has a wave like shape to generally correspond with the contour of the annular ridge 46 of the bearing housing 32 it is preferable to bias the diffuser shield 44 against the ridge such that the diffuser shield 44 forcibly abuts the ridge 46 a plurality of openings such as grooves 58 is provided in ridge 46 as shown in fig3 and 4 the grooves 58 are circumferentially spaced apart from one another and extend radially through the ridge.