A heat exchanger (HEX) for cooling air in a gas turbine engine is provided. An adjustable damper is provided. The adjustable damper may be for damping a movement of the HEX relative to the gas turbing engine. An adjustable damper may comprise: a first tube; a second tube located at least partially within the first tube; a housing coupled to the second tube; a moveable member, the moveable member comprising a contacting surface in contact with the second tube; an adjusting member adjustably coupled to the housing; and a spring member located between the moveable member and the adjusting member, the spring member configured to at least one of compress or decompress in response to adjusting member moving relative to the housing.