I have a 93 T100 with the 3.0L V6 3VZE that's consuming half a quart of oil every 1000 miles with no visible leaks, I want to try some seafoam high mileage in with the oil prior to my next oil change and see if it helps but have heard it can free up deposits that can clog up the oil passageways and cause engine problems, is this a legit concern? Vehicle has 205K and otherwise runs well with no issues.

 

A quart of oil in 2000 miles is not excessive consumption in a 200.000 mile plus engine.
Leave well enough alone and just check the oil level once in a while.
What weight of oil are you using??

 

10-30 full synthetic, rec'd weight per owner's manual.

 

I've used Rislone with some success regarding this issue. Either it works, or not at all.
You want something that will slowly melt the sludge and carbon to avoid big pieces breaking free and clogging things.
Much more frequent oil and filter changes will be in order, too. But that's not terrible, the fresh detergent in the new oil will also help clean things a bit.

The old guys who were hardcore used ATF, but that's a little trickier to do.

 

Any specific product of their many offerings that you recommend?

 

Engine treatment.

 

that's actually not bad for a worn-out v-6, built with 1980's technology, i don't get excited until i see consumption approaching a quart every thousand miles.

you might try to isolate the cause of the problem, for instance what i've done is add an oil catch can, try to control crankcase pressure, get a borescope to look at the combustion chamber, etc.

at 205k there is no question that in general a valve job would help, and if it's losing oil via the valve stem seals or even worn-out guides, you'd be directly addressing that... not sure that i'd bother at this point tho, and for me personally, i don't use additives.

 

I agree with the comments about oil usage per 1,000 miles. The only bad thing is typically once an engine hit that mark it tended to get worse at a faster rate. It was rather rare for an engine stay at that mark. And once oil use dropped below 1qt per 1,000 it typically got ugly.

 

I had a 22re that was pushing 300,000 that burned a quart of 10-40 every five or six hundred miles.
It still ran strong and did not foul its plugs.
Finally went down on head gasket failure.

 

Nice. But for many, 1 qt every 500 or so miles or so gets tedious to monitor, and if you're required to get bi-annual smog tests those start to get iffy.
But yes, you can buy a ton of oil as opposed to tearing an engine apart.