Hi mr scotty
I have a toyota corolla 2.0 xli 2007 model it has 175 000 kms i put the 15w40 mineral oil and i changed every 5 000 kms .
Do u think it s better to put the 10w40 semi synthetic oil for going 10 000kms and some money in maintenance?
Are there in damages in puting a semi synthetic instead of mineral oil in this vehicule?

NO, engines get used to oils, do not switch if you have no problems now