I know this is most probably the wrong group to ask, but nobody in the Vauxhall (Opel) group gave an answer.
1993 Corsa 1.5TD GLS, Manual, Isuzu Engine.My corsa once in a while overheats (boils over) for no apparent reason. I have changed the thermostat, pump, radiator and I have tested the cooling fan on the radiator, which kicks in at the right temperature. I noticed in the Haynes manual they mention there is an oil cooler and a oil cooler thermostat, can some kind soul let me know the purpose of these items and if they might be the cause of my problem?