Can I fix the leak with silicone?
Quick answer: No — don’t use household silicone to fix car leaks. Temperature swings make it shrink and lose adhesion. If a sealant is truly required, use an automotive-grade product; but most leaks come from perished gaskets or grommets and are best fixed by replacing the parts, not sealing.
You should not use silicone household sealants to repair leaks in cars because they degrade very quickly.
Cars are subject to sub-zero temperatures in winter, and when baked in the summer sun, the panels can get to well over 40ºC. This results in the silicone shrinking and losing adhesion fairly quickly.
If a sealant is needed, a suitable product, specifically designed for cars, from a reputable supplier such as Würth or Innotec is recommended.
The majority of leaks are caused by perished gaskets and grommets, which can be remedied by replacing the part with a new one. No sealant is required.
Written by Danny Argent. Last updated 03/09/2025 19:04
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