Melanie Reiff
Updated on Aug 11, 2022
The car heater bypass tube delivers coolant to the engine to prevent pressure build-up or overheating. Getting it replaced can save you from a costly engine repair down the road.
Driving too long with your car heater bypass tube malfunctioning can lead to major engine damage, which can be dangerous for you and other drivers. It’s best to get this checked out as soon as possible.
If you’ve got any questions, read this guide from car insurance broker Jerry. It explains the whats, whens, and hows of car heater bypass tube replacements.
The exact cost varies between different Mercedes-benz models. For example, newer vehicle models are usually made with more expensive materials, so recent or high-end models will cost more, especially if your service requires a part replacement. Use the table below to estimate the cost for your own vehicle.

What is a car heater bypass tube?

The car heater bypass tube, true to its name, bypasses the engine’s thermostat to allow small amounts of coolant into the engine. That means even when the car’s thermostat is off, small amounts of coolant are still being circulated. This prevents a build-up of pressure and allows for even cooling when the engine is started.
Issues with the car heater bypass tube can lead to your engine overheating. This can destroy your engine and lead to very pricy repairs.

When do I need to replace my car heater bypass tube?

The bypass tube is a sturdy, metal part, and was designed to last the lifespan of your vehicle. However, rust or other issues can lead to a need to replace your car heater bypass tube.
The car heater bypass tube is not inspected in routine car maintenance, so you need to be on top of any issues to keep your engine running correctly.
Here are signs there’s an issue with your car heater bypass tube:
  • You can smell coolant
  • Coolant (a yellow-green fluid) is collecting under your car
  • The engine regularly runs hot
Get this repaired as soon as possible—this simple fix can save you from massive engine repairs down the road.

How to replace a car heater bypass tube

Here’s a step-by-step guide to how your car heater bypass tube will be replaced:
  • Your car’s hood is opened
  • All the coolant is drained—it is highly toxic, so this should be handled with the utmost care
  • The old, defective heater tubes are removed
  • A new heater bypass tube is installed
  • The coolant is replaced and the hood is closed
After completing the replacement, your car will be run and the tubes will be tested for leaks.

How to find cheap car insurance

While you’re waiting at the repair shop to pick up your car, why not save some money on your car insurance? With the Jerry app, it only takes a few minutes to save hundreds of dollars on your yearly insurance bill.
After you download the app and answer a few quick questions, you’ll be given dozens of competitive insurance quotes from over 50 top providers. Just compare the quotes and choose the one that’s right for you.
Best of all, Jerry helps with your paperwork, making all sign-ups, switchovers, and cancelations a breeze.
Keep in mind that your location is another factor that determines the final cost of repairs. Areas with higher cost of living will usually have more expensive car repair services, especially if there’s less local competition. Check out the table below for an estimate of what Mercedes-benz drivers pay in different cities.
Jerry doesn’t just offer fair price repair estimates for Mercedes-benz drivers! Our team of writers has collected everything you need to know for every car. Here’s how much the repair costs for some popular cars:
CarTotal Cost EstimateParts CostLabor CostAverage Dealer PriceEstimated Service Duration
G25/G2500 Van
The cost of repairs might vary depending on which Mercedes-benz you drive, but there’s an easy way to save money for the services you need! Just download the Jerry app for help lowering your insurance premiums. In less than 45 seconds, Jerry collects all of your information from your existing insurer. Choose from competitive quotes from top insurance companies and Jerry takes care of the rest—securing your new policy and helping you cancel your old one upon request.
With an average annual savings of $887, Jerry can help you free up funds for the repairs your Mercedes-benz’s needs.