2006 H2 180k approx.

First off exhaust broken studs fixed years back (will also give tick at start up).

So, on to symptoms: engine tick at start up for 10 seconds or so (obviously +/- in your case) possibly “Low oil pressure” warning at start up or delayed showing pressure in gauge momentarily at start up.

Cause: Oil pickup tube o-ring is “flattened” and causing loss of suction at start up.

See attached pics, you could clearly see the oring was “flattened”. How many orings can you stand on its side and get a picture, lol.

oil pan needs to come off and 3 bolts for oil pickup tube removal. So, hours of labor to get a few dollar part replaced. If your doing this and you have external oil leaks already- you may want to do the front engine cover/front crankseal at same time since the sealing surface at oil pan is going to be removed anyway…with 20 years +/- on the original seal and gaskets- now is the time. Also your oil cooler lines and the seals for them. The front differential just needs to be unbolted and if you follow another post on this site- you don’t have to totally remove it, will drop enough with persuasion, unsure about 08/09).

Upon start up - pressure now instantly shows, no tick AT ALL, even if sitting for weeks!! Highly advise you do this, that oring is not going to fix itself and condition will continue to deteriorate. Plus you may stop many sources of external leaks you may presently have….

Hope this helps someone thinking they may have a serious engine issue and it can be as simple as this……

 

I’ll back this up with my own experience.



I did this repair on my 2007 H2 at 198k miles, and in my case it was actually worse than just a startup issue.



My symptoms:

• Startup tick
• Delayed oil pressure indication
• Oil pressure was low all the time, not just at cold start
• Pressure never really looked “normal,” even when warm

Once we got in there, the cause was obvious:

The oil pickup tube O-ring was completely flattened and hardened, no longer sealing at all. The pump was pulling air constantly, not just at startup.

Since I was already that deep, I went further than just the O-ring.



What I did at the same time:

• Replaced the oil pickup tube O-ring
• Installed a Melling high-volume / high-pressure oil pump
• New pickup tube brace
• Timing chain replacement
• Resealed the front timing cover
• New front crank seal
• Oil pan gasket
• Oil cooler line seals

Basically, everything oil-system and front-engine related that makes sense while the pan and cover are off.



Results:

• Oil pressure now comes up instantly
• No tick at all, even after sitting
• Oil pressure is now rock-solid and consistent around ~55 psi
• Engine is noticeably quieter and smoother overall

In my case, this wasn’t a “might happen eventually” problem, it was already happening full time. That O-ring was never going to seal again, and pressure was never going to improve on its own.
If anyone is seeing low oil pressure that doesn’t make sense on an otherwise healthy LS, don’t assume bearings or lifters right away. This is a very real and very fixable failure point.



Highly recommend addressing it sooner rather than later.