---
product_id: 8435813
title: "K-Seal HD"
brand: "k-seal"
price: "€ 49.13"
currency: EUR
in_stock: null
reviews_count: 13
category: "K Seal"
url: https://www.desertcart.fr/products/8435813-k-seal-hd
store_origin: FR
region: France
---

# One-step, no draining needed Heavy-duty for large engines Seals leaks in minutes K-Seal HD

**Brand:** k-seal
**Price:** € 49.13
**Availability:** ❌ Out of Stock

## Summary

> 🚀 Seal it, forget it—coolant leaks don’t stand a chance!

## Quick Answers

- **What is this?** K-Seal HD by k-seal
- **How much does it cost?** € 49.13 with free shipping
- **Is it available?** Currently out of stock
- **Where can I buy it?** [www.desertcart.fr](https://www.desertcart.fr/products/8435813-k-seal-hd)

## Best For

- k-seal enthusiasts

## Why This Product

- Trusted k-seal brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Fix Leaks Fast & Forever:** Permanently seals radiator, head gasket, freeze plugs & more in minutes
- • **Effortless One-Step Application:** Just shake, pour & drive—no draining or flushing required
- • **Engineered for Heavy-Duty Power:** Designed for commercial, agricultural & industrial vehicles
- • **Universal Coolant Compatibility:** Works seamlessly with all antifreeze types for ultimate convenience
- • **Trusted by Pros, Proven by Science:** Mechanic-approved, non-corrosive formula meets ASTM D3147 standards

## Overview

K-Seal HD is a professional-grade, multi-purpose coolant leak sealer engineered for heavy-duty vehicles. Its unique formula permanently seals leaks and cracks in radiators, head gaskets, freeze plugs, and more within minutes, without draining or flushing your system. Trusted by mechanics and independently tested to ASTM standards, it’s compatible with all antifreeze types and designed to enhance engine cooling reliability for commercial and agricultural engines.

## Description

Experience the ultimate solution to coolant leaks with the K-Seal ST5516 HD, a multi-purpose, one-step permanent coolant leak repair. Our powerful formula works seamlessly with all antifreeze, making it a universal fit type for all your needs. No need for draining or flushing your system. This heavy-duty sealer was designed specifically for HGVs, tractors, heavy plant and other commercial vehicles. The K-Seal ST5516 HD, also known as a head gasket stop leak, works by sealing leaks efficiently and permanently. It also doubles as a radiator stop leak, effectively putting an end to any leaks in your radiator. The permanent leak sealer is easy to use - just shake, pour, and go. This product excels in fixing cracks and leaks in several components including the radiator, head gasket, freeze plugs, cylinder heads, heater core, water pump casing, and engine blocks. With a single 8 fluid ounce bottle of our coolant leak sealer, you can treat up to 20 quarts cooling capacity. This heavy duty stop leak sealant is a must-have for all your coolant leak issues. So, forget your coolant leak worries with the K-Seal ST5516 HD. Experience the power of a seal stop leak that stops leaks permanently, offering peace of mind and extended life for your vehicle's cooling system. Trust the K-Seal coolant leak repair for a lasting solution to all your coolant leak problems.

Review: Worked Perfectly! - Vehicle leaking coolant, about 1gal per 1,000 mi driven. Dealer diagnosed as jiffy tight fittings on turbos with a repair estimate of $3,300. 2015 Ford F-150 - 3.5L Ecoboost with 140K miles so didn't want to put that kind of cash into a high mileage vehicle. Added as directed and leaks stopped immediately. 1K miles later, coolant level in the overflow tank has not gone down at all.
Review: It'll work on anything but bullet holes I think. - I just concluded a 7,000 mile drive from Georgia to Oklahoma, then to Cali and from there, Washington state and then back to Georgia in my 2002 Chevy Tahoe while hauling a 21' toy hauler heavy laden with toys. My Tahoe has an aftermarket radiator that produced a pinhole leak during travel. I couldn't directly locate the leak nor was I able to just replace the radiator as I was traveling. So I considered using a radiator stop leak but hesitant to do so as I didn't want to plug up my cooling system at all. I found this product and due to the reviews, decided to try it. It worked almost immediately after running the engine for a while to circulate the solution. And it still has not shown signs of leaking and no affect of the cooling capabilities either. I highly recommend this product!

## Features

- FIX IT FAST: Our multi-purpose solution works in minutes to quickly & permanently seal leaks in the radiator, head gasket, freeze plugs, block, heater matrix & water pump of heavy duty vehicles. Fixes most leaks in water-cooled engines
- STOP HOLES & CRACKS: With 1 step our unique formula will seek out each hole & crack, permanently sealing them, without any adverse impact on the efficiency of your engine cooling
- EASY TO USE: K-Seal couldn't be simpler & requires no draining or flushing; just shake, pour & go - shake the bottle, add the fluid to your coolant system & run your engine as normal
- HEAVY DUTY PERFORMANCE: Engineered for large engines & industrial use; suitable for commercial or agricultural vehicles. A permanent repair for the lifetime of the engine. Compatible with all types of antifreeze coolant
- PROFESSIONAL-GRADE RELIABILITY: Trusted by mechanics, our non-corrosive sealer delivers a durable & long-lasting repair, without clogging your cooling system. A cost-effective solution to engine coolant leaks, enhancing the reliability & performance of your vehicle’s cooling system. We've sold millions worldwide & are independently verified by university testing to meet ASTM D3147

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B002BJEG3U |
| Best Sellers Rank | #5,646 in Automotive ( See Top 100 in Automotive ) #32 in Antifreezes & Coolants |
| Brand | K-Seal |
| Customer Reviews | 4.4 4.4 out of 5 stars (1,593) |
| Date First Available | May 29, 2009 |
| Is Discontinued By Manufacturer | No |
| Item Weight | 1.19 pounds |
| Item model number | ST5516HD |
| Manufacturer | Solv-Tec |
| Manufacturer Part Number | ST5516 |
| Model | ST5516HD |
| Product Dimensions | 5.9 x 4.1 x 1.9 inches |

## Images

![K-Seal HD - Image 1](https://m.media-amazon.com/images/I/71gy7ybxZsL.jpg)

## Questions & Answers

**Q: Does it work on potentially warped heads**
A: No idea

**Q: how much do i need to pour in a diesel 1 ton cummins**
A: You need this one bottle for a Dodge 3500 hd.  I have this one bottle in my HD Freightliner 330hp MBZ engine hauling freight (54,000 lbs cap) 6 days a week and it stopped my coolant leak in the engine bay and heater core with no blockage and no.  My opinion, Many reviews say products dont work BECAUSE most people dont take care of their equipment and their vehicles are old, high mileage and no maintenance done.  None of the add to a tank products are as good as replacing with new parts but thats expensive, we get it.  This may or may not fix your problem but its a low cost gamble with a high probability of success.  Dont listen to the negative reviews.  If the problem comes back, your damage was too far gone and in need of replacement anyway.

**Q: Will this work with aluminum heads?**
A: It works equally well with cast iron or aluminum. Great Stuff. Not a long-term solution, but it will buy you a lot of time.

**Q: Tried using alumaseal, which isn't working.  will i need to flush the system before using the k-seal?**
A: I used the HD Truck bottle on my 1998 GEO Tracker ( used 1/3 of the bottle ) of K-Seal and it worked. I have used so many to no avail. To answer your question, I must have @ least 3 to 4 other sealers in my colling  system when I added K-Seal. It's been almost a year & no adverse effects having not flushed my radiator. 
Should I have flushed the radiator & the system? Yes, I should have.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Worked Perfectly!
*by J***S on December 17, 2025*

Vehicle leaking coolant, about 1gal per 1,000 mi driven. Dealer diagnosed as jiffy tight fittings on turbos with a repair estimate of $3,300. 2015 Ford F-150 - 3.5L Ecoboost with 140K miles so didn't want to put that kind of cash into a high mileage vehicle. Added as directed and leaks stopped immediately. 1K miles later, coolant level in the overflow tank has not gone down at all.

### ⭐⭐⭐⭐⭐ It'll work on anything but bullet holes I think.
*by I***N on November 21, 2025*

I just concluded a 7,000 mile drive from Georgia to Oklahoma, then to Cali and from there, Washington state and then back to Georgia in my 2002 Chevy Tahoe while hauling a 21' toy hauler heavy laden with toys. My Tahoe has an aftermarket radiator that produced a pinhole leak during travel. I couldn't directly locate the leak nor was I able to just replace the radiator as I was traveling. So I considered using a radiator stop leak but hesitant to do so as I didn't want to plug up my cooling system at all. I found this product and due to the reviews, decided to try it. It worked almost immediately after running the engine for a while to circulate the solution. And it still has not shown signs of leaking and no affect of the cooling capabilities either. I highly recommend this product!

### ⭐⭐⭐⭐⭐ This stuff save me about $20K! It works!
*by M***S on August 14, 2025*

I waited 5 days to write this review on my birthday. Mainly because I am so impressed with this product and I didn't know that it would hold. I'm not getting paid for this review and I rarely write reviews. A little history. I own a 2007 Mercedes E-63. This car is a beast and is a joy to drive. The dealership diagnosed a blown head gasket on the car. The report shows coolant mixed with the engine oil. My oil almost looked like a mocha espresso. A very bad sign. The car was immediately overheating. I was adding antifreeze every day. The dealership estimated repairs to start at $15K but could easily rise to $25K. Once the top of the motor is opened up I'm sure they would recommend new cams (4), new cam adjusters and of course new seals. A new crate engine for this car from Mercedes-Benz costs $57,000.00. After carefully reading the directions I added coolant with the bottle of K-seal after shaking it for 1 minute. Then I drove the car normally for 20-25 minutes. The car came up to temperature and stayed there. It didn't overheat! After feeling terribly about having to sell the car as a mechanic's special or donating the car I can instead enjoy driving the car daily. I did end up changing the oil 3 times before it didn't appear to have any more coolant in it. Thanks K-seal!

## Frequently Bought Together

- K-Seal ST5516 Heavy-Duty Multi-Purpose One Step Permanent Coolant Leak Repair, 16 oz, Pour and Go, Mixes with All Antifreeze, No Flushing Required
- PEAK 50/50 Prediluted Antifreeze and Coolant for All Engine Cooling Systems
- K-Seal ST3501 Pour and Go Head Gasket Sealer, 16oz, Permanent Repair for Blown Head Gaskets, Cracked Heads and Blocks

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*Product available on Desertcart France*
*Store origin: FR*
*Last updated: 2026-03-09*