Common Reasons a may Car Overheat in Stop & Go Traffic from the service professionals at Carr Subaru in Beaverton, OR

The BOXER® engine that powers your Subaru is driven by combustion, and this is a hot process. It's hot enough that it can cause damage to the engine unless there's a properly functioning cooling system in place. An overheating engine is usually a sign of some trouble with the cooling system--but looking at when the engine is overheating can sometimes help narrow things down.

If you've noticed that your engine is overheating only when you're idling in stop-and-go-traffic, there are a few possible causes. Once you've seen what they are, be sure to head to an authorized Subaru service center to have the problem taken care of immediately.

A close-up view of the temperature gauge in a vehicle, with the needle in the red.

3. Thermostat Trouble

The thermostat helps your engine warm up faster. When you first start your Subaru, the thermostat will stay closed so that coolant can't enter the engine as it warms up. Once the engine reaches operating temperature, the thermostat valve will open and the coolant will begin doing its job. If the thermostat isn't working as it should, it may not open, keeping the coolant from circulating between the engine and the radiator. If you're in traffic when this happens, you may notice the engine beginning to overheat.

Steam coming from an overheating radiator in a vehicle.

2. Low or Contaminated Coolant

If the coolant in your cooling system is contaminated, or if there simply isn't enough of it, you may notice the same symptoms. As the engine warms up, the coolant begins to circulate and cool the engine down. If you're sitting in traffic when the coolant starts flowing, but it can't do its job right, the needle in the temperature gauge may begin to rise.

A shot of an interstate entrance with lots of cars driving nearly bumper-to-bumper.

1. Broken Radiator Fan

If you notice your engine beginning to overheat while you're stopped in traffic, but the heat goes down again once you start moving, the most likely culprit is a damaged or broken radiator fan.

The radiator cools down the hot coolant from the engine by spreading it out over a large area and allowing air to flow over it. When you're driving at speed, the airflow from driving is enough to do this job. However, when your Subaru is idling, there's no airflow--and this is where the radiator fan comes in. It turns on when your vehicle is not in motion to keep air moving over the coolant.

If the fan is broken or damaged, the coolant that enters the engine will be too warm. There are many potential causes of a damaged or broken radiator fan, including electrical damage, a worn-out motor, or even debris or physical damage from an accident. The technicians at Carr Subaru will be glad to take a look and get to the bottom of the problem.

Schedule service online at Carr Subaru in Beaverton, OR
Order parts online at Carr Subaru
  1. Carr Subaru

    11635 SW Canyon Rd
    Beaverton, OR 97005

    • Sales: (877) 271-4560

Map Data
Map data ©2019 Google
Map data ©2019 Google

Carr Subaru

11635 SW Canyon Rd
Directions Beaverton, OR 97005

  • Sales: (503) 672-3370
  • Service: (866) 460-0188
  • Parts: (888) 627-4707