Originally Posted by ABN31B

seriously... you have to be a computer....

Originally Posted by ABN31B

GM actually had to stop making Blazers because their K.Y.L.E. unit had become self aware and knew more than the guys attempting the gen 3 redesign....

Originally Posted by swartlkk

GM has a technical service bulletin on this very topic. It does happen. Porosity in the casting can allow air to leak out of the rim. This can be diagnosed with a dunk tank and is evidenced by tiny bubbles forming on the surface of the rim between the beads. This isn't something that just starts happening one day though unless the rim has been damaged so...

Quote:
Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels

TECHNICAL

Bulletin No.: 05-03-10-003F

Date: April 27, 2010

Subject: Low Tire Pressure, Leaking Cast Aluminum Wheels (Repair with Adhesive Sealant)
Models:
2011 and Prior GM Passenger Cars and Light Duty Trucks (Including Saturn)
2010 and Prior HUMMER H2, H3
2009 and Prior Saab 9-7X
with Cast Aluminum Wheels

Supercede:
This bulletin is being revised to update the model years and the bulletin reference information. Please discard Corporate Bulletin Number 05-03-10-003E (Section 03 - Suspension).

Condition

Some customers may comment on a low tire pressure condition.

Diagnosis of the low tire pressure condition indicates an air leak through the cast aluminum wheel.

Cause

Porosity in the cast aluminum wheel may be the cause.Correction

1. Remove the tire and wheel assembly from the vehicle. Refer to the appropriate service procedure in SI.
2. Locate the leaking area by inflating the tire to 276 kPa (40 psi) and dipping the tire/wheel assembly in a water bath, or use a spray bottle with soap and water to locate the specific leak location.
   • IMPORTANT - If the porosity leak is located in the bead area of the aluminum rim (where the tire meets the rim), the wheel should be replaced.
   • IMPORTANT - If two or more leaks are located on one wheel, the wheel should be replaced.
3. If air bubbles are observed, mark the location.
   • If the leak location is on the tire/rubber area, refer to Corporate Bulletin Number 04-03-10-001F
   • Tire Puncture Repair Procedures for All Cars and Light Duty Trucks.
   • If the leak is located on the aluminum wheel area, continue with the next step.
4. Inscribe a mark on the tire at the valve stem in order to indicate the orientation of the tire to the wheel.
5. Dismount the tire from the wheel. Refer to Tire Mounting and Dismounting.
6. Remove the tire pressure sensor. Refer to Tire Pressure Sensor removal procedure in SI.
7. Scuff the INSIDE rim surface at the leak area with #80 grit paper and clean the area with general purpose cleaner, such as 3M(R) General Purpose Adhesive Cleaner, P/N 08984, or equivalent.
8. Apply a 3 mm (0.12 in) thick layer of Silicone - Adhesive/Sealant, P/N 12378478 (in Canada, use 88900041), or equivalent, to the leak area.
9. Allow for the adhesive/sealant to dry.
   • Notice: Caution must be used when mounting the tire so as not to damage the sealer. Damaging the repair area may result in an air leak.
10. Align the inscribed mark on the tire with the valve stem on the wheel.
11. Reinstall the Tire Pressure Sensor. Refer to Tire Pressure Sensor installation procedure in SI.
12. Mount the tire on the wheel. Refer to Tire Mounting and Dismounting.
13. Pressurize the tire to 276 kPa (40 psi) and inspect for leaks.
14. Adjust tire pressure to meet the placard specification.
15. Balance the tire/wheel assembly. Refer to Tire and Wheel Assembly Balancing - Off-Vehicle.
16. Install the tire and wheel assembly onto the vehicle. Refer to the appropriate service procedure in SI.