VW T6 Engine issues. Two of the more powerful diesel engines can be susceptible to engine failure although this is quite rare. These seems to affect the 180bhp and 205bhp Bi-Turbo Diesel models and is caused by a faulty EGR valve (see above). Due to age of the T6, most of these engine failures are covered under the original VW warranty but Given the pump and sensor have been replaced, if the hot oil at low revs cannot get above the lowest sensor pressure figure, then this could be onset of bearing/crank wear causing the oil to pass too easily. Cold oil will hold pressure as being less fluid. High revs will hold pressure as pump is working harder. L8Eqdc.