Auto & Tools · Permatex

Permatex Ultra Black Gasket Maker

The black, oil-resistant RTV that seals valve covers and oil pans with a factory look — a garage staple for a reason.

Formulated for maximum oil resistance on oil pans, valve covers and timing covers.
Sensor-safe, non-corrosive silicone that won't foul oxygen sensors.
Cures to a flexible black seal that blends in on modern engines.

$7.56

On Amazon when we checked (June 16, 2026) — live price may differ.

By Patrick Smith · Updated July 11, 2026 · How we review · We may earn a commission from Amazon links.

Price when checked: $7.56; on Amazon, June 16, 2026
Best for: It worked best for patient DIY builders sealing oil-wetted joints; worst for anyone…
Biggest complaint: The recurring complaint is the slow moisture cure — the recommended wait before service feels impractical…
Sources cited: 2; independent sources

Our verdict

The right pick for DIY engine sealing jobs where you can leave the vehicle overnight. Pros who need same-hour turnaround tend to reach for faster-curing products like The Right Stuff instead.

Reasons to buy

Users praise its dependable, leak-free seals across oil pans, valve covers and motorcycle cases, with experienced mechanics reporting years of use without a failure.

Reasons to skip

The recurring complaint is the slow moisture cure — the recommended wait before service feels impractical mid-job — plus tubes that harden, separate or lose caps in storage.

Permatex Ultra Black is the black, oil-resistant RTV that a generation of weekend mechanics reaches for on oil pans and valve covers — partly because it simply looks factory once cured. What the front of the tube doesn't emphasize is time: this is a moisture-cure silicone, and Permatex's own technical data sheet calls for parts to sit finger-tight while the bead skins over for about an hour, then a full 24 hours of cure before the engine returns to service. Forum mechanics who trust the seal it makes still grumble about that wait, along with a mundane failure mode nobody advertises: half-used tubes that dry out, separate, or lose their caps on the shelf. Buy it for the job at hand, not for the drawer.

What buyers say

Our summary of recurring themes in customer reviews on the Permatex Ultra Black Gasket Maker Amazon listing (read July 2026) — not quotes or endorsements.

Most praised

Users praise its dependable, leak-free seals across oil pans, valve covers and motorcycle cases, with experienced mechanics reporting years of use without a failure.

Most common complaint

The recurring complaint is the slow moisture cure — the recommended wait before service feels impractical mid-job — plus tubes that harden, separate or lose caps in storage.

Worked best for

It worked best for patient DIY builders sealing oil-wetted joints; worst for anyone needing the engine back in service the same day.

Frequently asked questions

How long before I can run the engine?

Permatex's data sheet specifies about an hour for the bead to skin over with parts assembled finger-tight, and 24 hours at room temperature for full cure before returning to service or refilling with oil.

Is Ultra Black really oil resistant?

Yes — oil resistance is its defining trait versus general-purpose RTVs. It's formulated specifically for oil pans, valve covers and timing covers, and it's sensor-safe.

Does it replace a gasket or just dress one?

On stamped covers and machined flanges it's designed to form the gasket itself. It's not for head gaskets or other high-pressure fiber-gasket applications.

Sources

Permatex Ultra Black Gasket Maker

$7.56 on Amazon when we checked (June 16, 2026). Amazon handles checkout, shipping and returns.

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