the updated part should be a permanent solution to this problem. Blower Motor Regulator - If this part fails, the climate control fan will not operate faster than approximately 50% power. Mercedes updated the regulator to improve its reliability, but the redesigned regulator requires the installation of a new blower motor. The old-style regulator, which is compatible with the existing blower motor, is no longer manufactured. The blower motor regulator may be replaced with the much less expensive W140 S-class blower regulator, provided that the E-class wiring harness is re-attached to the S-class regulator. Front Sway Bar Drop Links - While not a serious concern, most E-classes end up with a sub clicking or rattling sound from the front end. This is usually due to worn out front-end sway-bar drop links. These can easily be replaced by anybody with minor knowledge of vehicle DIY, for no more than around £20. Front Spring Perches - Some owners have reported rust problems on the front spring perches - the top perches, which hold the tops of the springs for the front suspension. The perches are spot welded to the chassis, and factory coated in a weatherproof mastic to stop their rusting, however in some rare occurrences, water gets behind the mastic causing the perches to rust and eventually to fail - leading to collapse of the suspension. The car remains controllable. This is a problem that Mercedes USA have acknowledged. The problem is not identifiable without first removing the mastic to check. Body corrosion - Most model year versions of the W210 displayed body rust, notably on European-sold cars. Rust would sometimes appear spontaneously on panels such as doors and roofs on cars less than a year old. In response to this problem, the manufacturer would in some cases change or repair the affected panels under warranty or good will. Mercedes-Benz has been criticized in the European press for not officially acknowledging this problem. This was due to problems introducing water-based paint technology within the German automobile industry, between the years 1998–2002. Window regulators - The power window regulator, essentially the mechanism that transfers power from the electric motor to the window, has a few plastic parts that can fail after several years causing the power window to stop operating. Cylinder Head Gasket - The cylinder head gasket on the M104 is known to fail, causing an oil leak at the rear