whats the diff. 5w30 5w20 oil

 

Please go through the Motor Oil U and come back with any more questions.

http://www.bobistheoilguy.com/motor-oil-101/

 

What Im wondering is I put 5w30 in my truck and when under a load (pulling a trailer up a hill) I get a rattle in the motor sounds like valves. would using differant oil cause that?

 

Are you using two oils with the exact same additive packages and the only difference is the viscosity? Also are you sure it's oil related and not a slight misfire under load?

 

Im sure its not a miss fire. I had the miss fire and new plugs fixed that. It sounds like a valve tap. Like an octane knock. It only did it going up hill, as soon as I went over the top it goes away.

 

Are you using two oils with the exact same additive packages and the only difference is the viscosity?
Are the results repeatable and happen every time with one oil verses the other? May just be a bad tank of gas.