Is it bad of i used the wrong oil?

I used 20w-50 instead of 5w-20

Added (1). I have a 2003 ford ranger with 155xxx miles

Drain it out, leave the filter and refill with the correct oil. Honest mistake - easily fixed. Yes it is bad because it is not the correct weight oil that the engineers at Ford recommends for your Ranger. Modern engines are designed with very tight tolerances. Using a 50 weight oil in an engine designed to use 20 weight will for sure damage the engine over time. You will not notice it in the short term but down the road you for sure will when the engine starts using oil and looses power. Why would you even think of using a weight that Ford does not recommend? Change the oil again As soon as possible and it could be a good thing for the engine to get the extra oil change and help clean it good. That can lower your gas mileage. If your engine has a variable cam, controlled by oil pressure, it will definitely affect its operation. Yes, that's wrong enough to cause problems.

Drain it and fill up with the right stuff. You'd better put the right oil in. 20w-50 is almost like gear oil. At 155k the heavy oil should not hurt it… It only gets heavy at extreme temperatures… Good luck. The higher the number, the thicker the oil. Thick oil seals piston rings better, so it is good for old cars. Thin oil is good for cold temperatures because engines start easier.

Yes it is bad because it is not the correct weight oil that the engineers at Ford recommends for your Ranger. Modern engines are designed with very tight tolerances. Using a 50 weight oil in an engine designed to use 20 weight will for sure damage the engine over time. You will not notice it in the short term but down the road you for sure will when the engine starts using oil and looses power. Why would you even think of using a weight that Ford does not recommend?

Change the oil again As soon as possible and it could be a good thing for the engine to get the extra oil change and help clean it good.

That can lower your gas mileage. If your engine has a variable cam, controlled by oil pressure, it will definitely affect its operation.

Yes, that's wrong enough to cause problems.

Drain it and fill up with the right stuff.

You'd better put the right oil in. 20w-50 is almost like gear oil.

At 155k the heavy oil should not hurt it… It only gets heavy at extreme temperatures… Good luck.

The higher the number, the thicker the oil. Thick oil seals piston rings better, so it is good for old cars. Thin oil is good for cold temperatures because engines start easier.