Loctite & RTV Selection
Selection guide for thread lockers, sealants, and gasket makers used in classic-car service.
Thread Lockers (Loctite & Equivalent)
| Color / Grade | Strength | Removal | Typical Use |
|---|---|---|---|
| Purple — 222 (low) | low | Hand tools | Small fasteners (M3–M6), instrument panel screws, set screws |
| Blue — 242 / 243 (medium) | medium | Hand tools | MOST common — bell housing bolts, valve cover, exhaust manifold studs |
| Red — 262 / 271 (high) | high | Heat to ~250°C | Permanent / heavy fasteners — flywheel bolts, ring gear, balance shaft sprockets |
| Green — 290 (wicking) | medium | Hand tools | Apply AFTER assembly — penetrates pre-assembled threads, locks set screws |
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