Supposed 03 4.8 LR4 with 90XXX miles.

Anybody know what they might mean?

I figure the top is a date.

 

 

I pulled off another cap and found the same markings on the bearing.

 

I have torn down several Gen 3 untouched 5.3 and 6.0 engines. Never ran across one where the rod caps had been marked on with a paint pen.

 

I’m a bot…

 

So I�m an old timer that�s just getting back into the LS hobby and I remember way back in the early 2000�s there were a couple TSBs out for piston slap and oil consumption issues in 4.8, 5.3, 5.7, and 6.0 motors at the time. While I don�t know the exact cause it was speculated that the issues were from either the low tension rings or bores that were slightly out of spec.

I can�t find the TSB info anymore but I believe GM actually replaced the pistons in some of these motors with pistons that had coated skirts and or rings. The early LS motors did not have OE coated skirts.

So if I had to guess either that engine was a slapper or a heavy oil consumer at some point and they at a minimum pulled the pistons to rering it if not put new slugs in. Thus the date on the cap.

As for the 0300. That�s either a tech employee ID or possibly the tech wrote the root reason he was in there P0300 (multiple cylinder misfire) which could trigger if the slap was bad enough or it was consuming enough oil. These are all SWAGs (sophisticated wild *** guesses). But that�s what I�d tell myself.

 

GM actually replaced entire engines in some cases where the engines were really noisy, and the owners pitched a big bitch. My 2000 vert had a noisy one. In the Summer, when I bought it, there was nothing. First Fall morning when temps were under 50�, the damn thing sounded like a diesel (Im NOT exaggerating!) for the first 30 seconds. I was told that some engines had slightly oversize bores, maybe .001" at most. I bitched, but not enough, because they did nothing but say it was "commercially acceptable." OK.....

 

Of all the LS engines I’ve been in, I’ve never seen the paint pen marks myself, but there have been a couple different threads here, made by folks who have come across an LS with paint pen markings on the caps. My theory is that it’s a warranty job as described above.