Why does my Promaster leak coolant?

Why Does My Promaster Leak Coolant?


The sight of a puddle beneath your Promaster van can be distressing, especially when it's coolant that's leaking. A coolant leak not only poses a threat to the engine's health but can also lead to overheating issues and subsequent breakdowns. The two most common sources of coolant leaks in Promaster vans: from the surge tank and from the oil cooler on the Pentastar engine.

Promaster Coolant Leak from Surge Tank


The surge tank, also known as the coolant reservoir or overflow tank, plays a crucial role in the vehicle's cooling system. It is designed to collect excess coolant that expands as the engine heats up, preventing over pressure in the cooling system. However, when a coolant leak occurs from the surge tank, it can raise concerns about the cooling system's integrity.

Several factors could contribute to a coolant leak from the surge tank:

1. Damaged Surge Tank:
Over time, the surge tank may develop cracks or other forms of damage. This can happen due to exposure to extreme temperatures, vibrations, or general wear and tear. Inspect the surge tank for visible signs of damage, such as cracks, leaks, or weakened areas.

2. Loose or Damaged Cap:
The surge tank is sealed with a cap to maintain the pressure in the cooling system. A loose or damaged cap can result in coolant leaks. Check the cap for any signs of wear, cracks, or improper sealing. Tighten or replace the cap as necessary.

3. Hose Connections:
The surge tank is connected to the radiator and other parts of the cooling system via hoses. Leaks can occur at these connection points due to loose or damaged hoses. Inspect the hoses for visible signs of wear, and tighten or replace them if needed.

4. Coolant Level:
An overfilled surge tank can cause coolant to leak. Ensure that the coolant level is within the recommended range when the engine is cold. Overfilling can lead to excess pressure, resulting in leaks. Follow the manufacturer's guidelines for proper coolant levels.

Promaster Coolant Leak from Oil Cooler on Pentastar Engine


The Pentastar engine is found in many Promaster vans. While known for its performance, a coolant leak from the oil cooler on the Pentastar engine can be a cause for concern. The oil cooler is responsible for maintaining optimal oil temperatures to ensure smooth engine operation. When coolant begins to leak from this component, it requires prompt attention.

1. Faulty Gaskets:
The oil cooler is sealed with gaskets to prevent leaks. Over time, these gaskets can degrade, leading to coolant seepage. Inspect the gaskets for any signs of wear, such as cracks or deterioration. Replace the gaskets if necessary.

2. Corrosion:
Corrosion is a common issue in cooling systems, especially if the coolant is not changed at regular intervals. Over time, corrosion can compromise the integrity of the oil cooler, causing leaks. Regular coolant flushes and replacements can help prevent corrosion-related issues.

3. Physical Damage:
The oil cooler is exposed to various external elements, and physical damage can occur due to road debris or accidents. Inspect the oil cooler for any visible signs of physical damage, such as dents or punctures. Replace the damaged component to prevent further coolant leaks.

4. Coolant Quality:
The quality of the coolant used in the system can impact its overall performance. Ensure that the coolant meets the manufacturer's specifications and is compatible with the Pentastar engine. Using the wrong coolant can lead to chemical reactions that may result in leaks.

In conclusion, diagnosing and addressing coolant leaks in your Promaster van is crucial for maintaining the vehicle's performance and preventing potential engine damage. Regular inspections, proper maintenance, and prompt attention to any signs of leaks can help ensure the longevity of your Promaster's cooling system. If you are unable to identify or fix the coolant leak on your own, it is recommended to seek the assistance of a qualified mechanic to address the issue and prevent further complications.

Remember, a well-maintained cooling system is crucial for the overall health and longevity of your vehicle's engine. Don't hesitate to invest time and effort into proper maintenance – it's the key to a reliable and efficient Promaster van. Give us a call today at 305-444-8881 to ensure that the coolant leak on your Promaster doesn't affect the lifespan of your vehicle's enigne. 

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