Rover K Engine - Head Gasket Problems

Head Gasket Problems

The K-Series engine has gained a reputation for head gasket trouble. This is due to a range of problems, including build tolerances, reduced block face stiffness, casting quality and material and cooling system layout. A number of changes were made over the years to improve the condition.

Amongst the first of the changes was the introduction of steel head locating dowels. Early versions of the K Series engine had steel dowels, but these were loose fitting and used as an assembly aid. Plastic dowels were then introduced to prevent head face damage on the assembly line and also as a cost saving. This engine had wet liners and a solid block top deck and was not known for being prone to gasket failure. The plastic dowels were carried forward to the redesigned K series which was then available in 1600 and 1800 capacities by using damp liners and an open block design. However, it became apparent that this engine had an issue with head gasket failure, which was partly due to lack of stiffness in the head/block interface. To help reduce this shuffling, steel dowels were reintroduced, but with a tight fit to fix the head securely to the block face. This reduced one mode of head gasket failure caused by movement between the block and head faces, but was only partly successful, because the dowels only helped in their local areas. The gasket itself was also subject to minor improvements to the sealing bead design over the years.

During its later years, the cooling system of some models was also modified by the introduction of a PRT (pressure-release thermostat). This allowed increased coolant flow at high engine loads, even before high temperatures were reached, and reduced the thermal shock the engine saw when a conventional thermostat was first opened. This thermal shock would cause differential expansion across the gasket face, causing relative movement between head and block.

A new design of head gasket has been available for several years from Land Rover which can be retro-fitted to all K-Series engines. This is of the MLS (multi layer steel) design. This has now been superseded by a new MLS design that is used in conjunction with higher tensile head bolts and strengthened oil rail (into which the bolts are screwed). A modified tightening method is also used with the new bolts. The effectiveness is yet to be proved.

Destined to be introduced with the Euro IV emissions compliant engine in late 2005 was the MLS gasket and strengthened oil rail. The aim of the latter is to improve engine rigidity. But this was never introduced by MG Rover Group, as the company had gone bankrupt by the time of the planned launch.

The N-Series engine (basically the aforementioned Euro IV-compliant K-Series) in the MG TF relaunched by Nanjing Automotive in September 2008, has these modifications as standard.