Frequently Asked
The Questions People Actually Ask Before They Buy
Straight answers, the same ones Dave gives on the phone before anyone spends a dollar.
Does head gasket sealer actually work?
Depends which one, and how bad the failure is. Most bottle sealers are built for minor seepage. Thermalweld has operated in the severe-failure segment since 1995, BBB A+ since 2002, with a documented 1,100+ repair field record and a published 95% success rate. Not every engine qualifies — that's what the 60-second check is for.
My mechanic quoted $4,500–$7,000 — is there an alternative?
On a car worth close to or less than that quote, yes — if it qualifies. Check the specific symptoms first, before spending anything.
Will it clog my heater core?
A fair question for any stop-leak product — ask directly and get a specific answer before you pour anything into a cooling system.
Does it work on a Cadillac Northstar?
Northstar failures are one of the most common cases in the field record, documented on video. Severity varies engine to engine — check yours.
Is there an option for diesel trucks?
Yes — engine-specific diesel kits, not a universal bottle. Diesel runs different pressures than gas, so a one-size-fits-all sealer is a red flag.
How is this different from BlueDevil, Steel Seal, K-Seal?
A public, checkable record instead of a number on a bottle: 1995, BBB A+ since 2002, 1,100+ field repairs, 69 five-star reviews.
A 60-second check before you spend anything. Check Now