'02 5.3L Knocking/Ticking only at highway speeds

[OR VietVet]

Ne benefit from the high volume. You don't need it. You are bone stock. Please bear in mind that after replacement of oil pump you will want to monitor the pressure and watch the oil level. I am not saying you will lose or burn oil but the level is crucial and want it right. Do a complete oil change obviously and use a new good oil filter. I always use NAPA brand gold oil filters. They are made by WIX and I personally think the quality is top notch. You can also use a new AC Delco filter and be ok.

Be aware that with that kind of mileage on the engine your tolerances at the crank bearings and cam bearings are slightly larger and the like new oil pressure may be slightly lower because of that. Good luck.

When you reassemble make sure all seal surfaces are "CLEAN". Lube the o-ring with oil before install. Oh, and did I say "CLEAN."

 

[Dozer]

I am getting a ticking/knocking on cold starts. Is that something I should be concerned about? I have a 2002 with 113,000 miles on it. No engine mods.

 

[dmperfection]

IMO you have a pressure problem from the oil pump area. These engines are known for an o-ring failure at the pick up tube attachment.

I dropped the pan today and the pickup tube seal was pretty bad. Still pliable, but was formed into a square shape--is that the shape of the original seal, or is that due to time and heat forcing a round o-ring seal into a squarish shape? Anyway, pick up a new tube with a nice thick green o-ring seal (might be Melling), but the tube is Sealed Power. I also picked up a new pump. I'm a creature of instant gratification and put it back together with same pan gasket for s**ts and giggles. Wow! What a difference. The first start up, I heard just a bit valve noise, but as soon as oil pressure came up, all my valve noise went away. The second start up was an instant 40+ psi with absolutely no valve train noise at all.

After full warm up, idle oil pressure settled at 34 psi, 1800 rpm is close to 50 psi. On the road, I got good pressure between 40 and 60 psi depending speed. No drop to zero after 30 miles of driving streets and highway.

Before, my testing gauge would sweep between 20 and 30 psi, then drop to zero at idle.

Now that I know the biggest culprit has been found, I'm tearing down again to take care of the pump. Hopefully new pump gives me a couple more psi.

stop driving it! until its fixed.

Oil pressure issued fixed and just about ready to drive the hell out of it!