Going to do my 250k mile service this week. Should I Seafoam before I change the oil or no? Its running great other than a small lifter tick.

I'm about to hit 275k with a service and have been wondering the same thing. Could there be any downsides to giving the crankcase a little clean up if there are no issues?

Some think Seafoam is "snake oil". Others brew up their own concoction. Plenty of YT vids on the good, bad and ugly of it.

I run Seafoam periodically, especially when smog testing is almost upon me. In the tank, and down the TB. I run some MMO in the oil anyway so I usually skip that part.

Probably a lot more things much more important for a quarter million mile service than seafoam. do it if you want, i have never done it, but i havent heard of bad things done by it that I recall, but that dont mean it is good, or that bad dont happen when used. If you dont use it, that likely will not cause a bad thing to happen either, at least that is my slightly educated assumption. Oh shucks, just flip a coin.

lettuce know how it goes.

Will do. Yes I realize there are more important things. I have already done a tuneup, got a bunch of fluids ready. Just thought if I am changing oil, probably should seafoam first.

Are you talking about adding Seafoam to the oil before you change it? Or are you asking about using it for a "top end" cleaning? Couple of ways to use Seafoam. Actually three ways if you count adding it to your fuel tank periodically.

If this engine has had very regular oil changes and other maintenance through the 250K, I would probably pass on either as your engine should really be pretty clean even at this mileage. If it hasn't had regular oil changes and or if there is evidence of any sludge in the engine or other fuel related symptoms, then a Seafoam crankcase treatment (or some other name brand mfg. engine oil cleaner) or the induction method might be helpful.

I have done regular oil changes for the past 20 years. However, when I cleaned the throttle body last week, it was pretty dirty. Maybe just a top end clean?

might look at....

https://www.cherokeeforum.com/f30/st...-4-0-a-226299/

The throttle body being dirty is normal and has nothing to do with the crankcase condition. Supposed to be cleaned every 30,000 miles at tune-up time.

Take a peek through the oil filler hole and see what things look like. If it looks sludgy, add a quart of Marvel Mystery Oil and drive it for 1000 miles before changing the oil. Might help with the lifter tick.

Cool, I am obviously not a mechanic. Appreciate the suggestions.

There is plenty of ebate on this. Is Seafoam a good product? Yes, however the directions for use are crap. The problem arises when you pour it down the throttle body enough to almost kill the engine. Whoopee, it made white smoke. Used like that does it clear out the carbon, yes. However at that concentration it can also take out your catalytic converter. To use it safely, pour it in the gas tank when it is a quarter full and take it for a nice long drive. It will clean out the combustion chamber. I have done this and verified it with a teardown afterwards and the cat lived to work another day