The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2018 Chrysler Pacifica Overheating - Coolant Flush or Thermostat?

0

Sarah K. · rep 0 · May 22, 5:56 AM · 1 replies · solved · Question

Vehicle: 2018 Chrysler Pacifica Touring L

Hey everyone,

I've got a 2018 Chrysler Pacifica Touring L with about 85,000 miles on it. Lately, I've noticed the temperature gauge creeping up, especially in stop-and-go traffic. It hasn't fully overheated yet, but it's making me nervous. I also got a check engine light a few days ago, and my OBD scanner pulled a P0128 code.

I checked the coolant reservoir, and it was a bit low, so I topped it off. The fan seems to be kicking on, but it still feels like it's running hotter than usual. I'm wondering if this is a sign I need a coolant flush, or if it's more likely a failing thermostat given the P0128 code.

Has anyone dealt with this on their Pacifica? Is replacing the thermostat a DIY job I can tackle in my garage, or should I just take it to a shop? Any advice on how to diagnose this further before I start buying parts would be greatly appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 5:56 AM

0

Hi Sarah,

The P0128 code (Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)) is a strong indicator that your thermostat is likely stuck open or opening too early, preventing the engine from reaching its optimal operating temperature. While it might seem counterintuitive for an overheating issue, a thermostat stuck open can sometimes lead to the engine struggling to regulate temperature efficiently, especially if other components like the water pump or radiator are also compromised.

Here's a breakdown of what to check and potential solutions:

  1. Verify Coolant Level & Condition: Ensure your coolant reservoir is at the correct level when the engine is cold. Also, inspect the coolant itself. Is it clear, or does it look sludgy or discolored? If it's dirty, a coolant flush is definitely in order, but it might not solve the P0128 code directly.
  2. Inspect Radiator and Hoses: Check for any leaks around the radiator, hoses, or water pump. Look for cracks, bulges, or signs of corrosion. A clogged radiator can also cause overheating.
  3. Thermostat Replacement (DIY Potential): Given the P0128 code, replacing the thermostat is a very common fix. It's generally a moderate DIY job for someone with basic mechanical skills and tools. You'll need to drain some coolant, remove the thermostat housing, replace the thermostat and gasket, and then refill and bleed the cooling system. Ensure you use an OEM or equivalent quality thermostat for your Pacifica.
  4. Bleeding the System: After any work on the cooling system, it's crucial to properly bleed out any air pockets. Air in the system can cause localized hot spots and prevent proper coolant circulation, leading to overheating.

Causes for P0128 and Overheating:

  • Faulty Thermostat: Most common cause for P0128.
  • Low Coolant Level: Can lead to overheating and sometimes trigger P0128 if the sensor doesn't read proper temperature.
  • Clogged Radiator: Reduces heat dissipation.
  • Failing Water Pump: Inefficient coolant circulation.
  • Cooling Fan Issues: If the fan isn't engaging or spinning fast enough.

When to See a Shop: If after replacing the thermostat and performing a coolant flush, the P0128 code persists, or the overheating continues, it's best to consult a professional. They can perform more advanced diagnostics, such as pressure testing the cooling system, checking for head gasket leaks, or diagnosing electrical issues with sensors or the cooling fan control module. Persistent overheating can lead to severe engine damage, so don't delay if the DIY fixes don't resolve the problem.

Menu

Help & account