Oil Leak?

This guide can help us fix it

https://www.2carpros.com/articles/engine-is-leaking-oil

From the dealer

Engine Oil Leak at Crankshaft Rear Main Oil Seal (Install Revised Crankshaft Rear Main Oil Seal Using Revised Rear Main Seal Installer and Remover Tools)
TECHNICAL SERVICE BULLETIN
Reference Number(s): 05-06-01-019F, Date of Issue: October 02, 2007
Affected Model(s):1986-2008 GM Passenger Cars and Light Duty Trucks (including Saturn); with 2.8L, 3.1L, 3.4L, 3.5L, 3.9L 60 Degree V6 Engine (VINs D, E, F, J, K, L, M, N, R, S, T, V, W, X, Z, 1, 3, 8, 9, W, R - RPOs LG6, LA1, LNJ, LG8, LL1 or LX9, L82, LL2, LB8, LHO, LG5, LB6, LE2 or LQ1, LH7, LC1, L44, LZ4, LZE, LZ9, LGD, LZ8, LZG)
Supercedes:This bulletin is being revised to add an Important statement on proper seal installation. Please discard Corporate Bulletin Number 05-06-01-019E (Section 06 - Engine/Propulsion System).

Related Ref Number(s): 05-06-01-019C, 05-06-01-019D, 05-06-01-019E, 05-06-01-019F
ARTICLE BEGINNING
SERVICE INFORMATION
IMPORTANT:This bulletin only applies to 60 degree V6 engines. Some of the discontinued 60 degree V6 engine VINs and RPOs may have carried over to other new model year engines and may no longer be a 60 degree V6 engine. So this bulletin may not apply. It is very important to verify that the following information is correct before using this bulletin:

Year of vehicle (e.g. N = 1992)
V6 Engine Liter size (e.g. 3.4L)
VIN CODE (e.g. X)
RPO (e.g. LQ1)
If ALL the information from the vehicle (year, size, VIN Code, RPO) you're working on can be found under the models listed above, then this bulletin applies to that engine. If one or more of the vehicle's information can NOT be found under the models listed above, then this bulletin does NOT apply.
IMPORTANT:This bulletin does not apply to 2004-2007 Saturn VUE models with 3.5L DOHC V6 Engine (VIN 4 - RPO L66) or 2005-2008 Cadillac CTS with 2.8L HFV6 Engine (VIN T - RPO LP1).

Condition
Some customers may comment on external oil leakage.
Correction
IMPORTANT:Before replacement of the new design crankshaft rear main oil seal, be sure the PCV system is operating correctly.

NOTE:The new seal described below comes with a protective nylon sleeve already installed in the seal. This sleeve assures that the seal is installed in the correct direction and also protects the seal from getting damaged during installation. Do not remove the protective sleeve from the seal; if removed, the installation tool (EN-48108) will not work.

A new design crankshaft rear main oil seal and installation tool (EN-48108) has been released. This seal incorporates features that improve high mileage durability. Replace the crankshaft rear main oil seal with the new design rear main oil seal, P/N 12592195, using the following service procedures.

Check the brake hose first then look for a torn boot on axle shaft. Cold be either.

Hi and thanks for using 2CarPros.com.

Honestly, it could be low oil pressure or a bearing issue. Keep in mind, when steel gets hot, it expands. Thus, often times the noise will become less noticeable. You mentioned that it only leaks when running. Have you located where it is leaking from? If there is no evidence of a leak, have you noticed any blue smoke behind the vehicle which could indicated it is burning the oil?

Take a look through this link and let me know if it helps.

https://www.2carpros.com/articles/engine-noises

Let me know,
Joe