BMW X3 Service & Repair Manual: Corrosion protection

NOTE: Following repairs, the corrosion protection work already begins with the correct removal of the underbody protection, anti-drumming layer and seam sealing in the repair area.

The PRODUCTS RECOMMENDED by BMW are optimized with regard to corrosion protection.

1.0 Removing and applying sealant:

1.1 Removing sealant:

IMPORTANT:

• Do not burn off PVC material (sealant) with an autogenous torch or similar or heat to temperatures above 180 ºC. This would generate highly corrosive hydrochloric acid and release harmful vapor.
• The new sealant does not adhere appropriately to burnt polyvinyl chloride material and hence subsequent rust creep is possible.

Remove PVC material with a rotating steel brush, or heat PVC to maximum 180 ºC with a hot air blower and scrape off with a spatula.

Remove PVC material with a rotating steel brush, or heat PVC to maximum 180 ºC with a hot air blower and scrape off with a spatula.

1.2 Applying sealant:

Prime and seal all weld seams that are sealed with sealant in original condition immediately after repair work. Replace damaged or removed anti-drumming layers.

NOTE: Required spray gun for sealant (order number 81 49 0 300 887).

Seal blind rivet with SEALANT (risk of corrosion).

2.0 Basics of cavity preservation:

Apply cavity preservation after all body repairs.

Concluding cavity preservation is the most important part of all corrosion protection measures.

Use the cavity protection spray only for smaller-scale straightening work where the parts in question are easily accessible. Use the PRESSURE CUP GUN for all other repairs. Cavity protection agent is available in different container sizes.

Use the relevant sensors with tubes for the different cavity areas.

IMPORTANT: Incorrectly performed cavity protection can, especially in the case of steel/aluminum joints, give rise to a non-calculable product liability and safety risk.

The best repair is worth nothing if the subsequent cavity protection measures are not conscientiously carried out.

2.1 Cavity preservation of steel parts:

New doors and lids must be sealed with cavity protection agent after being painted.

New sheet-metal parts or cavities, weld seams and folds formed by new sheet-metal parts must be sealed with cavity protection agent after being painted.

The cavities affected must be sealed with cavity protection agent after all straightening work.

2.2 Cavity preservation of aluminum parts:

New doors, lids and side panels made of aluminum are not sealed with cavity protection agent.

After all straightening work on aluminum components, the cavities affected must be sealed with cavity protection agent after being painted.

After all welding work (E52 only) on aluminum components, the cavities affected must be sealed with cavity protection agent after being painted.

Cavities, seams and folds formed from new sheet metal parts or extruded profile must be sealed with cavity protection agent after being painted.