Evans and Reid supply both conventional glow plugs as well as thermostarts for diesel engines. We stock these for 525 excavators, 138 tractor models, and 327 models of JCB Loadalls and backhoes.
The glow plug fits directly into the cylinder head and heat the fuel in the combustion chamber. The thermostarts heat the air in the inlet manifold prior to it entering the combustion chamber.
Both assist starting in cold conditions.