How long can I keep Sea Foam in the crankcase? So far it has been in for 3 days and 240 miles. I plan to get the oil changed Thursday but may go over the 300 mile recommendation on the can . Also, this is fresh oil (just had it changed) and my truck is a 2005 GMC Sierra 1500 5.3 v8 with 288K miles.
Hi Joshua. I will try to answer your questions in two ways. First, you can leave Sea Foam in your oil for the entire life of the oil interval with no concerns. We recommend adding 100 to 300 miles before every oil & filter change because it will turn the heavier residues to liquid in time for everything to drain out when replacing the oil. [Otherwise the sticky/heavier oil residue stays and builds in the crankcase.] Second is, your description suggests that you only have 240 miles on your oil. If that’s the case, there’s no need to change your oil until an oil change is due (3,000 + miles depending on useful oil life). Hope this helps!