I have an 01 Suburban with 130,000 miles running the 5.3 liter engine. Normally engine runs smooth as silk. However recently when pulling my travel trailer I get a lot of what sounds like lifter clatter after about 20 - 30 minutes. If I stop and shut engine down for a few minutes, the noise goes away for a while. I've recently changed oil and filter thinking I had a bad filter. The problem persists. Any ideas?
Thanks

Mike

 

Are you sure its not engine ping form the load? try running a higher grade of fuel

 

I can try higher fuel grade, but the noise sure sounds a lot like the lifter noise that's common when the engine is first started. Once the noise starts it doesn't stop when I slow. I have to shut the engine off for the lifter chatter to stop. I also notice a gradual drop in oil pressure as the noise starts. The pressure starts at 60lbs and eventually drops to around 40-45lbs. I pulled my camper twice last summer over longer distances without the slightest hiccup. This just started recently.

Mike

 

Oil is naturally thicker when its cool and thins some as it warms, consequently a higher initial pressure and then dropping. I wouldn't think that 40-45 is out of range for the mileage you have.
If it is indeed clatter from the lifters I would suspect oil level then possibly pressure...

 

Might try a hi-mileage oil and another filter. Not Fram.

 

Oil level is good.
I've gotten some advice from some of the gear-heads at my work. One recommends using Lucas oil additive. Another recommended frequent oil changes to work whatever is clogging the system out. I've considered an engine flush, but I've read nothing good about those. I've also heard that the seal on the oil sump goes bad and needs replacing. Do you have an opinion on any of those possible remedies? In particular the Lucas oil additive.
Thanks

 

So you lose any power when the noise starts?

FWIW I used a qt of tranny fluid in the crankcase in an old pickup that had sticking lifters and it took care of the problem. I'm not a proponent of using liquids to solve a mechanical problem but this truck was ready to scrap anyway.

 

It sounds like an oil contamination issue. What brand and quality of oil you use really does matter. The less money you spend on oil, the less protection you get!! You may have some trash in one or more of the lifters causing them to lose there pressure resulting in the chattering/clattering sound. I have used the oil system cleaners and I have had mixed results. If you have been changing your oil on a regular basis with low quality oil, the treatment should be fine. If you have a poorly maintained engine then this treatment is probably going to cause a bunch of leaks, as with older/high mileage engines they tend to absorb dirt and grime into the seals and gaskets. This a was true with on of the truck projects I bought a few years back. I hope the info helps out.