98 454 niose

[stockrahmba]

Any ideas?

 

I bought a used 98 Sub 2500, 454, 100,000 miles. When I bought it I listened to the engine real good when I started it (cold) and everything sounded good. I brought it home and did a compression check and all cylinders where real close to 160 lbs. Oil pressure runs about 25-30 psi idle and 45-50 psi above 1500 rpm (warm). The question I have is, when I did my first oil change a noise has appeared. After about the first 20 seconds I can hear a noise (loudest underneath the vehicle) that sounds like what has been described as piston slap. It's not a knock, nor does it sound like lifters. If I increase the rpm above idle or place the vehicle in gear the sound goes away and once the engine is fully warmed up the sound goes away. After driving 2000 miles on the oil change the sound became less detectable. I drove on a 500 mile trip towing a trailer and It almost completely went away. I just changed the oil again and the sound immediatly reappered. The truck uses about a pint of oil between oil changes.

 

Any ideas?

[vhato]

I dunno if this applies to your truck,

 

but the Camaro/Firebird/Corvette guys claim MANY Oil Filters Internally crush under pressure (Fram, K&N, AutoZone, Advance AutoParts). I did experience this first hand.

 

However, filters from Wix, General Motors and Mobil-1 are a tad restrictive at first but begin to flow well after use. This could be your problem.