BMW 320d GTBooked for an oil change.
The coolant reservoir was empty.

01 / BMW 320d GT

Checking coolant during an oil service at 245,432 km

The odometer read 245,432 km. Before changing the oil, we checked the coolant level and engine surroundings. No coolant was visible in the reservoir, and several dried coolant traces remained around the oil filter housing.

The low level and surrounding traces warranted a closer look. The owner also reported repairs at another workshop a few months earlier, so that history mattered when assessing the current condition.

02 / BMW 320d GT

A borescope view of the areas out of sight

We used a Snap-on borescope to inspect the mounting area around the oil filter housing. The closer view helped locate the coolant traces.

We also found an intake manifold bolt that was not properly secured. That finding should be distinguished from the cause of the coolant loss. Further inspection and monitoring were needed to establish whether coolant was still leaking after the earlier repairs or whether some traces were old residue.

“To know for sure, I think we'd need to take it apart.”
Technician, during the borescope inspection

03 / BMW 320d GT

Engine oil and filter service

We filled the engine with PETRONAS Syntium 5000 AV 5W-30 and fitted a new MAHLE oil filter. BG DOC Diesel Oil Conditioner was also added.

With the vehicle on the lift, we checked the underside and driveshaft area. Regular oil service visits also provide an opportunity to check coolant, oil leak traces and underbody condition.

04 / BMW 320d GT

Comparing removed filters with their replacements

The engine air filter and cabin filter were also replaced. We inspected the removed filters alongside the new parts and addressed the additional service items during this visit.

Selecting the correct filter for the vehicle comes first. We recommended genuine or OEM products to the owner.

05 / BMW 320d GT

Explaining the findings in the context of earlier repairs

We explained the coolant traces and intake manifold fastening issue to the owner, and suggested checking the earlier repair details with the workshop involved. The owner preferred to continue the investigation with NHC.

The engine oil and filters were serviced during this visit. Coolant level changes and any continuing leakage will be followed up. Where and why the coolant is disappearing remains an item to check at the next inspection.

Coolant maintenance guide →

06 / BMW 320d GT

An appointment makes time for inspection and explanation

This is why NHC works by appointment. Inspecting a vehicle, reviewing its repair history and explaining the findings all take time. When a closer borescope inspection is needed, as on this 320d GT, there must be time to carry it out.

We allow time for more than replacing the oil. We check coolant and signs of leakage, and explain what needs attention now and what requires follow-up. Regular visits help us notice changes in the vehicle's condition.

Regular maintenance guide →

BMW M5: five years of regular care →