My truck is a ’99 GMC Safari 4.3L.
Last July, I started getting a clattering noise when starting the cold engine that would last up to 5 minutes before it would go away. A chain store mechanic diagnosed it as a bad lifter, and recommended a used engine – $3500.
Put Sea Foam in oil, ran 150 miles, changed oil, engine was quiet, then the noise came back after 2 weeks.
Later, put Sea Foam in again, ran 300 miles, changed oil again and engine stayed quiet for about 9 weeks.
When it got colder (35-40F), noise came back, and oil pressure was 80 PSI on the cold starts.
Added Sea Foam again, and engine has been quiet now for over 2 weeks, and cold oil pressure is now normal (60 PSI).
Question: Can I run Sea Foam in my oil indefinitely? Or do I need to be changing it out at 300 miles?
Hi Alex. Our maintenance recommendation is to add Sea Foam to oil 100 to 300 miles before every oil change interval. You seem to have a sticky lifter (dirty)/lifter noise matter to overcome, so am going to recommend that you add Sea Foam when the oil is new and allow it to clean for the duration of your oil interval. Just keep adding it every interval… Sea Foam will progressively work away at those stubborn oil residues and deposits until there’s no noise whatsoever.