Will the oil viscosity in a car break down if the car is only driven 15 miles every 3 months?

My brother has a car that he keeps in mint condition. He only drives the car 15 miles every 3 months. He has not changed the oil in two years and it is still clear. I told him he should change it cause the viscosity has broken down. He claims that since the car is only driven 15 miles every 3 months and he keeps it in his garage and that the oil is still golden that it does not need to be changed? Is he right?Will the oil viscosity in a car break down if the car is only driven 15 miles every 3 months?
If you left gasoline sitting on a shelf for a year and went back to get it, would you pour it into your tank? Would it have the same quality it had when you first put it there? I say no, it would break down over time, just like oil, and other hydrocarbons. The oil still needs to be changed regardless of whether it is driven or not.Will the oil viscosity in a car break down if the car is only driven 15 miles every 3 months?
it will be hard to make him see anything but the oil is like the tires age is not always the factor the rubber in the tires will start to degrade just like the oil and it will not protect the most imporant parts of the engine rings bushing of the crankshaft valve parts etc.plus the emission section will not work proplery either but he should change the oil and filter etc at least 3 months to a year ask him to talk to mobil and see what they say or you can do it and then get it in writing from them nuf said
viscosity no, additives and the water the oil is collecting and helping rust the inside of that motor Yes (that's why they recommend 6 months/year for in date)....





I would change at least once a year but usually my line is 6 months
The oil doesn't loose the viscosity in 3 months, or 6 months, or two years in his driving conditions..... I'd still change it once a year maybe..... but he's not hurting anything.
It won't hurt the engine. If anything...the car setting will damage it as the oil seals will dry out. I'd try to drive it 100 miles a month and change the oil once a year. Good luck.
the first answerer is right, in my own opinion, oil will not lose its ability to lubricate the engine, or its viscosity, or thickness, but in a vehicle that isn't driven, temperature changes from hot to cold, and so forth, will cause condensation to build up inside the crankcase, and you don't want moisture recirculating through the various internal components of the engine. Because where there is metal and water, there will be rust. change it every 3 to six months, and i recommend at least running the engine at least once or twice a month, for at least 15 to 20 minutes at a time.