I just finished replacing the headgasket (HG) on my neighbor's 2010 Corolla 1.8. The vehicle was a recent purchase and despite having a documented 5K oil change history for the last decade, I think the headgasket failure caused a moderate amount of sludge to form inside the engine.
I cleaned the valve cover, camshaft housing and lower oil pan in a parts washer so all of those parts are now sparkly clean. However, there is still a decent amount of build up inside the upper oil pan and in other inaccessible areas.
He is trying to spend as little as possible on this car since he isn't sure how long it will be kept for. The engine was refilled with Valvoline Restore and Protect 0W20. Would it be safe to just proceed with a 5K interval going forward, or is it absolutely imperative for the oil to be changed in 500-1000 miles?
I cleaned the valve cover, camshaft housing and lower oil pan in a parts washer so all of those parts are now sparkly clean. However, there is still a decent amount of build up inside the upper oil pan and in other inaccessible areas.
He is trying to spend as little as possible on this car since he isn't sure how long it will be kept for. The engine was refilled with Valvoline Restore and Protect 0W20. Would it be safe to just proceed with a 5K interval going forward, or is it absolutely imperative for the oil to be changed in 500-1000 miles?