tapping noise in motor

i've got a 1996 s-10 blazer w/4.3 the oter day i noticed a knock coming from the front of the engine. but not a hard knock like a spun bearing. more like piston slap. my question is how long before this becomes an expenseve fix and can i put an oil additive in to help quite for the time being. actually this is my daughters vehicle and limited cash flow. the blazer has app. 110,ooo mi. and had normal service done. thanks for the help.

Hi, welcome to automotive forums. It's pretty hard to pin down what the noise is and even harder to estimaste how long it'll go.

Going by what you said, if it's a piston/pin/skirt then it could go for thousands of miles, but may also increase the expense if let go.

Maybe some tests will help pin it down.

Is it worse when cold/hot?
Is it worse when rpm is constant/varying?
Is it worse when loaded/unloaded/steady?

How is the hot/cold oil pressure?
When did it start?
How long has been knoking?

Ticking? clicking? could it be an accessory in front?