A method for reducing the formation of deposits on the inner walls of a tubular heat exchanger through which a petroleum-based liquid is flowing comprises applying one of fluid pressure pulsations to the liquid flowing through the tubes of the exchanger and vibration to the heat exchanger to effect a reduction of the viscous boundary layer adjacent the inner walls of the tubular heat exchange surfaces. Reduction of the viscous boundary layer at the tube walls not only reduces the incidence of fouling with its consequential beneficial effect on equipment life but it also has the desirable effect of promoting heat transfer from the tube wall to the liquid in the tubes. Fouling and corrosion are further reduced by the use of a coating on the inner wall surfaces of the exchanger tubes.