If under warranty I would stick with the viscosity recommended to make a warranty claim easier! Otherwise, my answer would be no there is little difference between the two and 5w30 should be no problem.
Would like to go to a good Dino. 5W20 holds up in the heat?
Warrenty issues (fears?) is EXACTLY why I stay with 5-20, even in our eternal Texas heat. I grit my teeth, use full synthetic as a hedge against thermal degradation, and look foeward to the day I can put 5-30 in my Honda freely! I urge you to use synthetic 5-20!
I have gone thru motorcraft blend, syntec, mobil1, PP and now GTX. GTX has by far been the quietest oil of them all in my application. From what I read here it is the thickest 5w-20 out there.
I never worry about using 5W-20 or 0W-20. It seems to me this is the only place that tries to scare guys out of using 5W-20 because it makes noise. Not because there are millions of motors having oil related failures using this grade of oil.
I have gone the way of finding a solution by changing brands not weights of oil I use and it has worked great for me.
That's my opinion and nobody has to agree with it if they don't want to.
I didn't know there was a 5w20 dino oil. I thought there only was a blend & full syn
It is marketed as a conventional, but from the word here you need grp II+ or grp III to make 5W-20.
there is a blend offering from castrol marketed in grey bottles as opposed to the white GTX and black syntec bottles.
Today's engines,run what is recomended.The lifters in a GM 5.3 will rattle if 5w30 is not used.The MDS systems in the 5.7 hemi powered cars: the 300C,Charger and Magnum will not work right if 5w20 is not used
i am going to put in ST 5-30 next time in my focus...right now i am running M1...i can hardly see how we can hurt our engine by running 5-30 esp after reading all the " i just add oil and dont change stories" here
Either one makes no real difference. They are so close together that I just split the difference and run the 30 weight. 20 weight works good too, I just don't like the volatility, less film strength. I really doubt the difference in wear at startup time is significantly different. If you're really not sure, just run a 50:50 mix, or adjust the mix so your hot cSt of the virgin oil is around 9.8 or 10. 20 weights start out at about 8.6, so the difference between using a 9.8 vs an 8.6 is negligible. Above 9.3 is by definition 30 weight, so we are all around one or the other side of the border. Even I had a 7000 mile run planned this summer, so I'm actually using a 10w30 synthetic.
I switch from dino 5w20 to synthetic 5w30 and got ~ 2 mpg improvement in my Hyundai.
Of course, this would not be a valid (anecdotal) experiment because you have tested 2 variables( weight and oil type) at the same time.
It's quite possible you could have gotten a >2 mpg improvement had you switched to a synthetic 5w20.
To the OP, if you're out of warranty run the 5w30, it won't hurt a thing. If you're under warranty, you're on your own. I'd run the 5w20.