"Simple to use and fast results."
Block-Check Blue Combustion Leak Tester Kit
A practical DIY combustion leak tester for diagnosing suspected head gasket failure. Get a clear yes-or-no result in under two minutes. The kit includes UK-made non-toxic Block-Check Blue fluid, a twin-chamber tester, a tapered silicone bung for most petrol, diesel, and LPG cooling systems, a printed quick-start guide, and a full instruction manual.
- ✅ Universal fit for petrol, diesel & LPG engines
- ✅ Safe, non-toxic, UK-made formula
- ✅ Includes everything needed for ≈ 15 tests
- ✅ Full instruction manual + printed quick‑start guide
- ✅ Fast UK shipping with Royal Mail 1st/2nd Class options
30 mL Block‑Check Blue™ fluid
Twin‑chamber tester
Tapered silicone bung
Quick‑start card
Full instruction manual
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How it works
1) Draw gases through fluid
Insert the tester into the expansion tank and let the engine idle. Exhaust gases (if present) bubble through the blue fluid.
2) Watch the colour
Blue stays blue = no leak. Blue turning green/yellow = combustion gases detected.
3) Decide with confidence
Get a definitive yes/no in under 2 minutes so you can repair, negotiate, or rule out a head gasket issue.
Buying help and test guidance
Use these pages to choose the right combustion leak tester, run the test correctly, and understand the result before you buy parts or book further diagnostic work.
Combustion leak tester hub
See the main commercial page for block tester, head gasket tester, and combustion leak detector intent.
How to test for a blown head gasket
Follow the step-by-step process for a safe, usable block tester result at home or in the workshop.
Results explained
Understand blue, green, yellow, weak positives, and the next checks to run after the test.
Manuals and downloads
Access the quick-start guide, safety data sheet, and support notes for this head gasket test kit.
Delivery, returns, and company details
Marketplace checkout happens on Amazon UK or eBay UK, but you can still review delivery and returns information and learn more about LeakLogic UK before you buy.
Real demo and buying checks
Watch the current LeakLogic promo demo to see the Block-Check Blue tester in action.
What you can verify before you buy
- Read the quick-start guide, PDF manual, and safety sheet
- Check delivery and returns information
- Review business details for LeakLogic Ltd. in Devon, United Kingdom
- View the current Amazon UK listing
- View the current eBay UK listing
Review summary on this page is sourced from the current Amazon UK listing: 4.9 out of 5 from 23 global ratings, alongside verified-purchase review excerpts shown below.
Recent verified Amazon UK reviews
"What a great piece of kit... everyone needs one before you buy a car to check if there is an expensive issue."
"Does does what it's suppose to do and easy to use. Good for the money."