BOSCH Duraterm High Speed Rod Glow Plug 0250403021 GLP237 - Genuine OEM Quality

Because they are wearing parts, their functional performance should be regularly checked by an expert. Motorway use is the easiest condition for oil, the speeds are fairly consistent and rarely push the engine hard, there is plenty of air flow to help cool the engine and the oil has a chance to get up to temperature and flow properly.