Dealership overfilled ls2 engine oil

[pavelow]

Us TBSS guys fill our LS2s with 7 quarts of oil to prevent oil starvation on hard acceleration due to the front sump oil pan GM put on these trucks. Doesn't hurt anything.....helps keep the rod bearings alive.

 

[HangFire]

When my truck was new I had some free dealer services to use up, so I paid the differential for "full synthetic" oil and still came out ahead of doing it myself. After one such change I challenged the "QS 4x4" on the receipt and the service manager came out with a bottle of QS 4x4 Semi-Syn (don't get excited, 4x4 has been made in both semi-syn and full syn by QS). He was sure PO'd when I told him that's not what I was paying for.

His guys drained and refilled and I was on my way. Later I checked the oil and sure enough it was a full quart over. Almost half a quart because of the full oil filter and the rest because they dumped the whole 5 quarts into a 4.4 quart sump. The engine manual does warn against overfilling.

That engine burned/consumed oil for the next 110K miles, but I'll never know if it was the overfill or if it is just the norm for the 3.9L V6, a known mudder of an engine with a TSB for leaky/sucking intake manifolds and a known head crack problem that trashes valve seals.

 

[pavelow]

Certain LS2s have known oiling issues due to front sump oil pans. The GTO and TBSS use a front sump oil pan that is well known to cause oil psi drops/starvation when the oil pump pickup gets uncovered during hard acceleration or cornering if running the factory recommeded oil quantity of 6 qts. Overfilling the pan to 7qts is a band aid fix that helps with the starvation issue and for some, is all they will ever need to keep their bearings alive. More drastic cases require custom oil pans and/or a dry sump oiling system. Some guys even go with a Accusump oil accumulator. In the end, they all help to keep the engine from destoying itself.

It is well documented that overfilling the LS2 oil pan does not cause any harm. A TBSS owner said it took almost 9qts of oil before being too full became an issue. No need to run that much though....7 does the job just fine.