Hi, I need some advice on my 06 with a 5.3. I recently purchased this clean 2WD Tahoe with 135,000 miles. A week after taking it home we were driving down the freeway and heard a ticking from the engine. I put the transmission in neutral and cracked the throttle and the noise followed the rpm's. We get off the freeway, rolled the window down to listen and the noise was gone. I get home and open the hood while running and I can see the A/C tension pulley moving all over the place. Seeing as the engine was quiet I figured it was my source of the noise. I replaced the A/C tensioner, belt, accessory drive belt tensioner , belt, idler pulley, water pump and thermostat. As I was refilling the coolant with the engine running the thermostat opened and at that instant I heard a lifter start ticking. Since the coolant was full and I saw I had around 35-40 psi on the oil pressure gauge I took it for a drive and half way around the block it stopped ticking and never came back. Sitting in a drive through a day later and after about two minuets it started to tick again, we drove off and the ticking stopped. Again oil pressure looked good.

I started to search forums and found this is a common problem with LS engines. I performed a flush of the engine and no sludge came out and the oil looked clean however, the tick came back while driving. I have pulled the truck off the road until I get this sorted out. My next step is to inspect and replace the oil pump pick up tube o-ring which along with a pan gasket I purchased from Chevy.

My question is on the oil pump there is a bypass valve and spring that can cause low oil pressure issues. Should I replace the bypass valve and or the spring while I have the oil pan off and is there a stiffer bypass spring I could install to raise oil pressure by about 10 psi or so? I don't want to go too high and over pump a lifter or cause other high pressure issues. Has anyone else delt with this lifter issue? Any and all thoughts are welcome.

Thanks, Chris.

 

What did you end of figuring out with this problem? I have similar issue and most threads I see have the issue on startup, but mine usually starts shortly after you start driving and eventually goes away.

 

My oil pump pick up tube o-ring was toast, flat on the sides and brittle. Installed a new one from Chevy along with an oil pan gasket and we are good to go. Cost about $50.00 for the parts plus oil and filter. The oil pressure on start up is about 52 psi or so and hot idle is over 40 psi. The engine rattle although slight on cold start is now silent even after sitting for a couple of weeks.

I made this repair back in October and was not able to get on here for one reason or another until now. It is like drinking through a straw with a hole in it. I think when enough air gets mixed in the system while you are at a constant rpm like sitting at idle or freeway driving is when you lose pressure and a lifter gets starved.