Change semi synthetic x mineral oil
 

My Honda Civic is a year 2002, EX 1.7 VTEC.
I was using semi synthetic oil (10w30) in the last 8000km and I changed the oil by another semi synthetic (10w30), but I don't know if the API / brand is the same of the previous oil.
When I run for the first like 15km, no problems, but when the engine is very hot, also in a hot day (30 degrees celsius in Brazil), sometimes the oil light blinks when I run the car at idle or when the engine rpm suddenly goes down.
I also notice that this oil seems to be very thin, when I take the dipstick it seems to flow very easily.
Could my problem be just the "wrong" type of oil?
I want to change it back to the original recommended oil in the vehicle manual (10w30 mineral), may this solve the issue?
Another question, if I just change the oil to a mineral, do I need to replace the oil filter that was running on semi synthetic (I ran just about 300km with it)?
Thanks.

Re: Change semi synthetic x mineral oil
 

what part of Brazil?

Re: Change semi synthetic x mineral oil
 

Rio de Janeiro

Re: Change semi synthetic x mineral oil
 

so very hot year around.

synthetic tends to be more stable, not supposed to be the problem.
Keep the filter, that does not matter.
is oil level correct?
could be some debris clogging parts of the oil system.
Is there any bent parts in the oil pan? If yes, it could be blocking the oil catch up.
or oil pump is not working well.

Re: Change semi synthetic x mineral oil
 

Thanks!
Yes, the oil level is correct, although when it was changed (not by me) they put a lot more (4 liters) but I removed the excess and now it is right in the top level marker of the dipstick.
In the oil pan there is a slight bent part, but not too hard so I think that's not it.
Thanks.