Trunk Water Leaks Despite New Taillight Gaskets - Comprehensive Resealing Guide

Body/Interiorintermediate✓ Community Verified

Problem

Water accumulates in the trunk and rear fender wells of MK3 Supras even after replacing the taillight gaskets, which is the most commonly suspected cause. Multiple additional leak points exist around the rear hatch area that degrade with age.

Water pooling in trunk under spare tireWater accumulating in rear fender wellsWater streams from corners of hatch shroud when trunk is openedWater collected on inside panel covering rear wiper motorTaillight malfunction and dash error light from water intrusion into lamp modulesWater leaks during rain but not always from garden hose testing

Root Cause

Multiple age-related seal failures beyond just the taillight gaskets. The most common additional culprits are the rear hatch glass bottom trim seal, rear quarter window seals, hatch trim bolt holes, rear spoiler mounting holes, rear side marker light seals, taillight housing cracks from age, and the power antenna opening. The factory seals and adhesives degrade over 30+ years, creating multiple simultaneous leak paths.

Confidence

High confidence — Multiple community members agreed on this solution

View Original Thread →Posted July 2020 on SupraForums.com