Rick's Free Auto Repair Advice

Heater core bypass

How to perform a heater core bypass

Many SUVs and vans have rear heater cores to heat the back of the vehicle. Replacing a leaking heater core can cost a small fortune. If the front heater core works, one far less costly option is to perform a rear heater core bypass.

Rear heater core replacement cost

Depending on the vehicle, replacing a rear heater core can be an easy or difficult job. Here are some examples of the cost

To replace a rear heater core on a:

2000 Ford Explorer, the labor to remove and replace the rear heater core is about 3-hrs and the heater core is $150, making this a $500-$600 repair.

2000 Chrysler Town and Country van, the labor is 4-hours and the heater core is $250, making this about an $800 repair.

2000 Cadillac Escalade, the labor is just 1.4-hours and the heater core is $265, making this a $500 repair.

If you don’t want to spend the money to replace the rear heater core, you can perform a heater core bypass.

How to bypass heater core

Tools required:

Hacksaw, cut-off tool or reciprocating saw with metal blade


Flaring tool


Heater core bypass hose, also called a heater core

ICT Billet 551699 Heater Core Bypass Hose

Heater core bypass hose

crossover hose

Buy a heater core bypass hose

2 Hose clamps to match the diameter of the heater core bypass hose

Performing a heater core bypass is pretty easy, especially on a rear heater for an SUV or van. Drain the cooling system. Then locate the heater tubes under the vehicle and cut them using a cut-off wheel, reciprocating saw or hacksaw. Once you’ve cut the metal tubes, remove the burrs with a file. You’ll be clamping on a heater delete bypass hose to the metal pipes below the vehicle and you don’t want them to slip off so you have to perform one more step.

Use a flaring tool to bend a VERY slight flare on the end of the hose. Do NOT make a full flare. You want just enough flare to prevent the hose from slipping off, but not enough to cut into the hose.

Install the heater core bypass hose

Slide the hose clamps onto the metal tubes first. Then slide bypass hose onto both heater tubes. Locate the hose clamps in front of the flare and tighten.

Remove air from the cooling system

Refill the cooling system. Then use a handheld vacuum

power steering whine noise

Mityvac MV8000 Automotive Test and Bleeding Kit

pump to remove the air pockets.

©, 2018 Rick Muscoplat

Posted on by Rick Muscoplat

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