NHC MOTORS · SERVICE RECORD
2011 BMW 520d Coolant Leak – Pressure Test and Hose Replacement
This 2011 BMW 520d, with 144,855 km on the odometer, came in with a coolant leak. Checking underneath, we found traces of coolant on the undercover, so before touching any parts we started with a cooling system pressure test to pinpoint where it was escaping.
2011 BMW 520d, 144,855 km — brought in for a coolant leak, coolant traces found on the undercover
Cooling system pressurized with a Snap-on pressure tester to locate the leak
Coolant hose replaced with a genuine BMW part and coolant refilled
Owner advised to keep an eye on the coolant level for a while after the repair
01 / NHC MOTORS
Coolant Traces on the Undercover
Fluid traces were visible on the undertray. A coolant leak may reach the ground, but it can also collect on a tray and be less obvious to the driver.
This car received a cooling-system pressure check and hose replacement, rather than simply topping up the coolant.
02 / NHC MOTORS
Why We Use a Pressure Tester to Find the Leak
We connected the Snap-on pressure tester and pressurized the cooling system to locate leakage under pressure.
Traces on the undertray alone may not identify where a leak starts. The hoses and connections need to be examined together.
03 / NHC MOTORS
Replacing the Hose with a Genuine BMW Part
The removed hose and replacement were compared before installation. The photographs show the new hose in BMW packaging alongside the old component.
Hoses work under heat and pressure. Connections and sealing areas should be checked alongside the hose itself.
04 / NHC MOTORS
Refilling the Coolant and What to Watch Afterward
With the hose replaced, we refilled the coolant to complete the job.
After pickup, we recommend keeping an eye on the coolant level in the expansion tank for a while. If the level starts dropping again, that is a sign another area needs inspection — in that case, come back for a check rather than repeatedly topping up.
Questions about this work
My coolant level keeps dropping slowly — do I need to get it checked right away?
Low coolant can lead to engine overheating, so finding the cause comes first. Pressurizing the cooling system lets us locate the leak even with the car standing still.
Does replacing a hose fix a coolant leak?
The leak location differs from car to car, so the right order is to repair whatever the pressure test identifies. On this car, the job was completed with a hose replacement and coolant refill, and we advised the owner to watch whether the coolant level holds.
Related guides and work
Losing Coolant, or Seeing Traces Where You Park?
Rather than repeatedly topping up, the first step is a pressure test to find where the coolant is escaping. When you book a consultation, let us know how often you have been adding coolant, whether any warning lights have come on, and where you have seen traces on the ground — it helps us focus the inspection quickly.
We explain the scope of any repairs and the estimate before proceeding with your approval.
Call 031-258-1617Book on NaverBy appointment only · Gwonseon-gu, Suwon