I use Castrol motor oil for my pro.
I usually use SAE 20/50 but just recently I bought SAE 50.
I didn't realise that it was SAE 50 until after I drain out my old oil and I couldn't go anywhere to purchase or exchange what I bought because it was a sunday and I couldn't leave the car without oil since it's a daily driven car.

Would that in any way affect the engine?

 

holy ****...you ran 50 weight oil in your Mazdaspeed??? oh god. You have screwed the pooch my friend.

 

it's not a mazdaspeed
normal 1.5l engine, '99 model
you guys don't have that there.

so what, i should change the oil?

 

for some reason I assumed you had a mazdaspeed protege!

The problem with your oil choice is that the engine is designed for a 30weight oill. All of the clearances and oil channels are designed for that certain viscosity. When you put in something thicker like a 40 or 50 weight oil you basically stretch the engine out. If you go back to running a 30weight oil you'll have leaks and smoking problems (most likely). This is a common problem I saw when I worked for that Quick Lube. A lot of poeple would switch heavier oil in the winter and then thinner oil in the summer time. this would cause all sorts of leaks and oil burning.

I would try to install an oil pressure gauge and make sure you're getting the proper amount of oil pressure through your engine...There's a possiblity that by "stretching" out those clearances when you switch to a lighter oil you won't have the proper amount of pressure anymore.

 

Shouldnt it be vice versa ?

 

oops. busted, you're right.

 

Rods right, not only that the reason the multi weight oil was made was so during start up the 5-10 weight oil gets to the head faster. After the engine warms up the oil thikens to 30. If you use anything thiker than 30 it take longer to pump up to the heads and that causes all kinds of problems. Plus it robbs HP. I had a hot rod that I used 20w50 and the Penzoil guy gave us a class and I learned that its not a good idea. I use 10w30 in every thing. If you live up north I would use 5w30. I just hope it isn't to late.

 

Well I live in Trinidad, that's just south of the equator and when I purchased the car they told me to use castrol and my uncle told me that I should use 20/50 and that's what i have been usin' the whole time (about a year and a half) but like i said, i recently put in just plain 50 without checkin' it until after.