So I am doing my 10 hour Oil change and can not find Penzoil Marine 15w40 oil anywhere. i did find the Penzoil Heavy Duty 15w40 Oil at wallmart that has all the API certs except instead of CI-4 it has CI-4 Plus. Will it be a good oil to use? Here is a link:
http://www.pennzoil.com/products/Lon...eavyDutyDiesel