Coolant heat up time?

[pmg]

Purely by chance last night I was returning home across the South Downs from Petworth. By the time I reached the A27 near Fontwell, all was well warm and oil at 95%. On entering the A27 dual carriageway, I gave it full blast in sport and taking the revs to 5000 before hitting 70 just before Fontwell roundabout. At that point oil temp had risen over the few seconds of high revs to 105 deg c . I had just never noticed that before. As I proceeded down Fontwell avenue at the 40 limit, the oil temp almost instantly dropped back towards 95 deg C

[Jim S]

The thermostat is two stage, the first stage will bypass the radiator to allow the engine to warm up quicker. Once it starts to open it closes off that route and the coolant then goes through the radiator.

The oil cooler acts as a heater for the oil to help it get up to temperature quicker using the coolant which is heating up quicker than the oil. Then of course the coolant then helps to cool the oil once the oil is hotter.