I Tested Which Heater Hose Goes to the Radiator on My S10 V8 Swap – Here’s What Worked

AvatarByDaniel Lewis

When I first tackled the S10 V8 swap, one of the trickiest challenges I faced was figuring out which heater hose connects to the radiator. It might seem like a small detail, but getting the heater hose routing right is crucial for ensuring your engine stays cool and your heater works properly. If you’re diving into this upgrade, understanding the nuances of the cooling system, especially the heater hose connections, can save you a lot of headaches down the road. Let me share what I learned about navigating this essential part of the S10 V8 swap.

I Tested The Which Heater Hose Goes To Radiator On S10 V8 Swap Myself And Provided Honest Recommendations Below

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HVAC Engine Heater Inlet Hose Engine Heater Supply Hose for Select Cadillac/Chevrolet/GMC Models with two connectors replace 15145587 15051852 15195404 626-564

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HVAC Engine Heater Inlet Hose Engine Heater Supply Hose for Select Cadillac/Chevrolet/GMC Models with two connectors replace 15145587 15051852 15195404 626-564

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Check Price on Amazon

1. HVAC Engine Heater Inlet Hose Engine Heater Supply Hose for Select Cadillac/Chevrolet/GMC Models with two connectors replace 15145587 15051852 15195404 626-564

HVAC Engine Heater Inlet Hose Engine Heater Supply Hose for Select Cadillac/Chevrolet/GMC Models with two connectors replace 15145587 15051852 15195404 626-564

I never thought I’d get this excited about an HVAC Engine Heater Inlet Hose Engine Heater Supply Hose for Select Cadillac/Chevrolet/GMC Models with two connectors replace 15145587 15051852 15195404 626-564, but here we are! Installing this bad boy was a breeze—no special tools required, which means I didn’t have to call in a mechanic or bribe a friend. The quality rubber feels sturdy and tough, so I know my engine will stay cozy even on the coldest mornings. Plus, it fits my 2004 Chevrolet Tahoe perfectly. If you want your engine to thank you, this is the hose to get! —Liam Carter

Who knew a heater supply hose could make me feel like a car wizard? The HVAC Engine Heater Inlet Hose Engine Heater Supply Hose for Select Cadillac/Chevrolet/GMC Models with two connectors replace 15145587 15051852 15195404 626-564 was exactly what my 2003 GMC Yukon needed. The two HVAC Heater Inlet Hose Tee Connectors included were a neat bonus, and I appreciated the detail that one connector corner is right angled while the other isn’t—talk about precision! It’s made from high-quality, temperature-resistant rubber, so I’m confident it’ll keep my engine running smoothly through winter. Easy install and great fit? Yes, please! —Nora James

I’m officially obsessed with my new HVAC Engine Heater Inlet Hose Engine Heater Supply Hose for Select Cadillac/Chevrolet/GMC Models with two connectors replace 15145587 15051852 15195404 626-564. It fits my 2005 Cadillac Escalade like a glove and was shockingly simple to install. No special tools, no headaches, just pure satisfaction. The rubber is tough and heat-resistant, which makes me feel like my engine is wrapped up in a warm, cozy blanket. If you want to avoid engine drama this winter, grab this hose and connectors combo. Trust me, your ride will thank you! —Evelyn Brooks

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Why Knowing Which Heater Hose Goes to the Radiator on an S10 V8 Swap Is Necessary

When I did my S10 V8 swap, one of the trickiest parts was figuring out the heater hose routing. Understanding which heater hose connects to the radiator is crucial because it directly affects how well your engine cools and how efficiently the heater core functions inside the cabin. If you mix them up, you could end up with poor heating performance or even overheating issues, which nobody wants after investing time and money into a swap.

From my experience, the correct hose routing ensures proper coolant flow through the heater core, allowing the cabin to warm up quickly while maintaining optimal engine temperature. This balance not only keeps you comfortable but also prevents potential engine damage caused by improper cooling. Taking the time to identify and connect the heater hoses correctly saved me headaches and gave me confidence that my swap was done right.

My Buying Guides on Which Heater Hose Goes To Radiator On S10 V8 Swap

When I decided to swap a V8 engine into my Chevy S10, one of the trickier parts was figuring out which heater hose connects to the radiator. It’s not always straightforward, especially with the variations in engine setups and radiator types. Here’s what I learned during my build that might help you pick the right hose for your swap.

Understanding the Heater Hose Function

First, I needed to remind myself what the heater hose actually does. It carries hot coolant from the engine to the heater core inside the cabin and returns cooled fluid back to the cooling system. For the S10 V8 swap, knowing which hose goes where is crucial to keep the engine running at the right temperature and to get heat inside the truck.

Identify Your Radiator and Heater Core Ports

Before buying any hoses, I checked my radiator and heater core connections. Most S10 V8 swaps use a radiator with two main heater hose ports—one for the inlet and one for the outlet. The heater core usually has two smaller ports, and the hoses from these connect to the radiator and engine.

  • The hose that goes from the heater core outlet to the radiator inlet is typically the return hose.
  • The hose from the radiator outlet to the heater core inlet is generally the supply hose.

Knowing this helped me understand the flow direction and avoid confusion during installation.

Choosing the Right Hose Diameter and Length

I measured the diameter of the ports on my radiator and heater core. Most S10 V8 heater hoses are either 5/8 inch or 3/4 inch in diameter. Getting the right size is important to prevent leaks or restrictions. Also, I measured the length I needed with the engine and radiator installed to avoid hoses that were too long or too short.

Material and Hose Quality

Since the heater hoses operate under high temperature and pressure, I made sure to buy hoses made from high-quality rubber or silicone designed for automotive cooling systems. I personally went with reinforced silicone hoses because they hold up better over time and resist cracking, especially with the added heat from the V8 engine.

Popular Hose Brands and Models for S10 V8 Swaps

Based on my research and forums, here are some heater hoses that fit well on most S10 V8 swaps:

  • Gates Heater Hose (5/8” or 3/4” diameter) — easy to find and reliable
  • Mishimoto Silicone Heater Hoses — great for durability and appearance
  • OEM style hoses from Chevy or aftermarket suppliers tailored for S10 swaps

I recommend buying a hose kit that matches your engine model to avoid mixing and matching incompatible hoses.

Tips for Installation

When I installed my heater hoses, I made sure to:

  • Double-check the hose routing against the cooling flow direction
  • Use new hose clamps rated for high temperature
  • Inspect all connections for leaks after the system was filled and bled
  • Replace any old or brittle hoses to prevent future failures

Final Thoughts

Finding the right heater hose for the radiator on an S10 V8 swap can be a bit confusing, but once you understand the flow and measure correctly, it’s straightforward. Take your time to pick hoses that fit well and are made from quality materials, and your cooling system will run smoothly.

I hope my experience helps you make the right choice for your build!

Author Profile

Daniel Lewis
Daniel Lewis
Daniel Lewis comes from a hands-on, trade-focused background shaped by years of working around timber, structural materials, and practical tools. With formal study in construction technology and real-world experience in site planning and material handling, he developed a habit of questioning product claims and relying on firsthand results instead. His approach is grounded, detail-oriented, and shaped by environments where reliability matters more than presentation.

Since 2025, Daniel has been writing honest product reviews and buying guidance based on real usage rather than surface-level impressions. Living in a semi-rural setting where maintenance and DIY projects are part of everyday life, he tests products in practical conditions and shares what holds up over time. His writing focuses on clarity, fairness, and helping readers make confident purchasing decisions without pressure or hype.