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Mitsubishi Eclipse 2007-2012 HVAC Heater Hose Replacement Guide

Keep your Eclipse's heat working and prevent engine damage by understanding when to replace your HVAC heater hoses.

4 minutes to read 2007-2012 Mitsubishi Eclipse
Difficulty
3/5
Est. Time
1.5 hrs
DIY Doable?
✅ Yes
Shop Labor
$85-$125
🚫 Do not drive — Driving with a significant coolant leak can quickly lead to engine overheating and catastrophic damage.
Key Takeaways
  • A failing heater hose can lead to critical engine overheating; address leaks immediately.
  • Symptoms include coolant leaks, a sweet smell, lack of cabin heat, and visible hose damage like cracks or swelling.
  • Aftermarket brands like Gates, Dayco, and Continental are reliable and cost-effective alternatives to OEM parts.
  • Always replace hose clamps and consider replacing both heater hoses at the same time for a complete repair.
The HVAC heater hoses in your 2007-2012 Mitsubishi Eclipse are a critical part of both the heating and engine cooling systems. These rubber hoses carry hot engine coolant from the engine to a small radiator called the heater core, which is located inside your dashboard. A fan blows air across the hot heater core to warm up the cabin. The coolant then circulates back to the engine to continue the cooling cycle. Essentially, these hoses allow your engine to share its heat with you on cold days.

Symptoms of a Failing Heater Hose

A bad heater hose on your Eclipse can cause problems ranging from inconvenient to severe. Because the hoses carry engine coolant, a leak can lead to serious engine damage if not addressed. Here’s what to look for:

  • Coolant Leaks: This is the most obvious sign. You might see puddles of green, pink, or orange fluid under your car. Leaks often start where the hoses connect to the engine or the firewall.
  • Visible Hose Damage: Over time, the rubber hoses can become hard, brittle, and crack. You may also see swelling or bulging, which indicates the hose is weak and could burst.
  • Sweet Smell: If a hose has a small leak, you might smell a sweet, syrupy scent inside or outside the car. This is the smell of hot antifreeze.
  • No Cabin Heat: If a hose is clogged or has failed, hot coolant can't reach the heater core, 🎬 Watch how to check if your heater core pipes are hot. leaving you with cold air blowing from the vents.
  • 🎬 Learn more about identifying symptoms of a failing heater core.
  • Engine Overheating: A significant leak will lower the coolant level in your system, causing the engine temperature gauge to rise into the red. Never drive an overheating vehicle.

Engine Overheating is Critical

If you notice your Eclipse's temperature gauge climbing, pull over immediately and shut off the engine. Driving with an overheated engine can cause catastrophic damage, such as a blown head gasket, which is a very expensive repair.

Choosing the Right Aftermarket Heater Hose

For the 2007-2012 Eclipse, the original equipment (OEM) hoses are good quality, but aftermarket brands offer a reliable and more affordable alternative. Since these hoses are primarily made of rubber, age and heat cycles are their biggest enemies. Aftermarket brands like Gates, Dayco, and Continental are well-established and produce quality molded hoses that are designed to fit just like the original parts.

When choosing between these brands, owner and mechanic experiences are often mixed, with fitment being the most commonly cited issue. However, all three are considered reputable choices.

  • Gates: Often considered a top-tier aftermarket brand, known for good fitment and quality materials engineered to resist electrochemical degradation.
  • Dayco: A solid and widely available option. Some users report Dayco hoses can be slightly thicker or have minor fitment differences from the original, but they generally perform well.
  • Continental: Another premium brand that produces hoses to OEM specifications. They are a reliable choice for durability and proper fit.

Pro Tip: When replacing a heater hose, it's highly recommended to replace the hose clamps as well. Spring clamps can lose their tension over time, and using new ones ensures a tight, leak-free seal. It's also a good time to inspect other cooling system components like the radiator hoses.

Cost of Replacing an HVAC Heater Hose

Part/Service Estimated Cost
New Aftermarket Heater Hose $20.66 - $73.15
New OEM Heater Hose $40 - $95
Shop Labor $85 - $125
Total Professional Replacement $105 - $200

Note: The provided shop labor costs from one source seemed to include the part price, leading to a higher total estimate of $372-$412. The table above separates these costs for clarity. Prices can vary based on your location and the specific hose being replaced.

Frequently Asked Questions

Are there any recalls for the 2007-2012 Eclipse heater hoses?

No. Searches of the National Highway Traffic Safety Administration (NHTSA) database show no specific recalls for the HVAC heater hoses on the 2007-2012 Mitsubishi Eclipse. There is a Technical Service Bulletin (TSB-11-55-003) related to the HVAC drain hose, but this concerns water draining into the cabin, not the heater hoses that carry coolant.

Is it difficult to replace the heater hoses myself?

For a DIYer with some experience, it's a manageable job. The difficulty is moderate, primarily due to access. The hoses connect to the firewall at the back of the engine bay, which can be a tight space. You will need to drain some coolant, so be prepared to capture and dispose of it properly. The job typically takes 1-2 hours.

🎬 See a step-by-step guide on replacing Eclipse heater core hoses.
Should I replace both heater hoses at the same time?

Yes, it is highly recommended. Both hoses have been exposed to the same age and heat cycles. If one has failed, the other is likely not far behind. Replacing them together saves you from having to do the same job twice in the near future.

What's the difference between a heater hose and a radiator hose?

Both carry coolant, but they have different jobs. Radiator hoses are much larger in diameter and connect the engine to the radiator to handle the main job of cooling the engine. Heater hoses are smaller and specifically route coolant to the heater core to provide heat for the cabin.

Symptoms Of A Bad Heater Core You Should NOT Ignore
Symptoms Of A Bad Heater Core You Should NOT Ignore
Heat dont work? Check to see if the Heater Core pipes are HOT every car has them
Heat dont work? Check to see if the Heater Core pipes are HOT every car has them
Replacing Heater core Hoses. 2G Eclipse 420A Engine
Replacing Heater core Hoses. 2G Eclipse 420A Engine

Technical Specifications

OEM Part Numbers: MN133418

Hoses are pre-molded to fit the specific engine (2.4L 4-cylinder or 3.8L V6). Made from EPDM rubber to resist heat and chemical degradation. Meets SAE J20R3 specifications.

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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.

Year Coverage
This article covers the HVAC Heater Hose for:
  • Mitsubishi Eclipse: 200720082009201020112012
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