2000 JGC (4.7L) Gas Engine Sounds Like Diesel...

[tStar]

Hi,

My 2000 JGC is a gasoline engine with 230k's, and very well maintained (oil changes on schedule, recently changed plugs, new radiator, run mid grade and higher fuel alternately, etc.)

Recently it started sounding more like a diesel when it starts up in the mornings.

The noise is noticeably loud for the first 45 seconds to about 1 minute, and then starts quieting down gradually there after.

After about 3-4 minutes, it sounds normal again.

Does anyone have an idea what this could be?

Thanks.

[Bob D.]

It sounds like you're describing typical valve train/lifter noise; lifters leaking down overnight then pumping back up.
Based on this I would say first check the oil level and condition, change oil and filter if they are dirty. Also check the oil pressure gauge, it should read around 40 psi at idle. If the oil, filter, and oil pressure are good, at 200k plus miles the lifters may just be leaking down, nothing to do except rebuild the motor and replace the lifters. Just make sure the engine is getting properly lubricated.

As long as they pump up and quiet down after a few seconds it's not a big deal. You can try an oil additive in the crankcase and see if it helps free up any sticky lifters.
Remember that's based on what you stated -- it may be something entirely different -- but it sounds like classic lifter noise.

[tStar]

Thanks for your answer Bob D.

I will try the oil additive.

Any particular brand you would recommend?

[Bob D.]

Any particular brand you would recommend?

I haven't used one in a while but just read the can, you want an oil additive that says "frees sticky lifters" or something to that effect.