NHC MOTORS / Guides / Car maintenance
NHC MOTORS · MAINTENANCE GUIDE
What should a service include beyond replacing parts and fluids?
During a service, we choose oils and parts to suit the car, then check fasteners, fluid levels and operation after fitting them. The examples below follow a Bentley Mulsanne serviced from 2023 to 2026. We also service BMW, Mercedes-Benz and Korean cars using the specifications and procedures for each model.
The service at a glance
| Who it is for | Used cars with uncertain history, collection cars and owners planning regular care. |
|---|---|
| What we check | Service history, current condition and applicable vehicle specifications. |
| What we do | Agree the scope, select suitable products and carry out the work. |
| Before handover | Check assembly, levels and operation; explain the next priorities. |
In this guide
- Start with what your car needs
- Use the specified oil and verify the level
- Follow the fluid change through the system
- Clean the surfaces that locate the brake disc
- Check refrigerant, compressor oil and operation
- Let the battery test determine the next step
- Wheel care includes cleaning, balance and alignment
- Leave with the results and a plan for the next service
- Four years of care
- Three work videos
01
Start with what your car needs
Scheduled maintenance uses previous service records and the condition of the car today to decide what needs attention. Mileage, elapsed time and storage conditions help determine what to do now and what to check again later.
Luxury and rare models require careful preparation of parts, tools and access procedures. Protecting nearby components during removal and refitting also takes time.
This is useful when a used car has an uncertain history, when a collection car is rarely driven, or when an owner wants the wider condition checked during an oil service.
- 01Review history
- 02Inspect condition
- 03Agree priorities
02
Use the specified oil and verify the level
Engine, transmission, power steering and differential systems have different fluid requirements and checking procedures. The applicable vehicle specification determines the product and method.
During the 2023 Mulsanne service, we drained the engine oil, passed synthetic oil through the engine and removed the remaining oil by suction. We also replaced the filter. Shell Helix Ultra 5W-30 and BG MOA were used. During the transmission-fluid change, we selected the gears in turn and checked the response. We also cleaned the engine bay and covers.
After a fluid change, level and assembly checks follow the procedure for the model. Any flushing or additive treatment is discussed after reviewing the condition and application requirements.
- 01Confirm specification
- 02Change fluid and filter
- 03Check level and assembly
03
Follow the fluid change through the system
Power steering fluid in the 2023 Mulsanne was changed repeatedly while the steering wheel was moved from side to side. Samples 1–11 in the photo record that process; NEW on the right is fresh fluid. They show the visible colour change during the work.
The number of repetitions depends on the vehicle and how the fluid change is progressing. The samples show the change in colour; colour alone cannot establish the oil’s performance.
For the brake fluid, both reservoir chambers were checked and fresh fluid was supplied from above while fluid was bled at the wheels. Rear differential oil was also drained and replaced.
04
Clean the surfaces that locate the brake disc
In 2025, the Mulsanne discs were checked for thickness, machined and fitted with OEM pads. The decision to machine a disc depends on its applicable thickness limits and damage condition.
After removing the discs, we found debris on the hub contact surfaces. We cleaned those surfaces so the discs could seat properly, prepared the backs of the pads and reassembled the brakes.
- 01Check machining suitability
- 02Clean the hub surface
- 03Refit and check operation
05
Check refrigerant, compressor oil and operation
The 2025 Mulsanne air-conditioning work checked the R-1234yf label, specified charge quantity and suitable compressor oil. Refrigerant type alone does not establish the charge quantity or oil requirements for every vehicle.
We switched the air conditioning on again after the work and checked its sound and operation. During that check, the previous compressor noise was no longer audible.
06
Let the battery test determine the next step
NHC checks battery type, rating, temperature and charge state along with starting and charging performance. The result determines whether to recharge and retest, replace the battery or investigate repeated discharge.
A replacement must have the appropriate technology, capacity and vehicle specification. Registration or learning procedures follow the requirements of the particular model.
- 01Test the battery and charging system
- 02Recharge, replace or investigate
- 03Follow the model-specific procedure
07
Wheel care includes cleaning, balance and alignment
In 2023, wheel-weight adhesive was removed, followed by iron-remover cleaning, steam cleaning and drying. Protected contact points were used during tyre removal. The Mulsanne was balanced on the Hofmann equipment then in use, aligned through repeated adjustments and road-tested.
NHC now also measures radial force variation under roller load with Hunter Road Force equipment. Where appropriate, tyre-to-wheel matching is adjusted and measured again. Centring, wheel runout and tyre condition are checked as well.
Wheel balancing checks mass imbalance, road force checks force variation under load, and alignment checks wheel geometry. At a later visit, previous settings can be compared with current measurements to explain what has changed.
| Wheel balance | Mass imbalance without roller load |
|---|---|
| Road force | Force variation under roller load |
| Alignment | Wheel direction and geometry |
08
Leave with the results and a plan for the next service
After the work, we explain what was replaced or adjusted and the results of the checks. We set out any further work in order of priority and identify what needs checking at the next visit.
Road-test scope is agreed in advance. Owners who wish to avoid adding mileage to a collection car can request no road test; we then check the items that can be assessed while stationary.
Cost depends on the model, products and work required. We explain the proposed scope and estimate before proceeding with your agreement.
The same Mulsanne, four years of care
See the work in three videos
Select a thumbnail to watch on YouTube. Each part shows a different stage of the 2023 service.
Wheel cleaning, tyres and alignment
Adhesive removal, cleaning, protected tyre work, balancing, alignment and a road test.
Watch on YouTube ↗Engine and transmission oils
Draining, filter installation, transmission-fluid service and cleaning.
Watch on YouTube ↗Power steering, brake and differential fluids
Eleven fluid samples, brake-fluid supply and bleeding, and rear differential service.
Watch on YouTube ↗Frequently asked questions
Do you only take high-end imported cars?
We service imported cars such as BMW and Mercedes-Benz, as well as Korean cars. For each model, we choose suitable oils and parts, take the necessary measurements, tighten fasteners to specification and check the car after the work.
My car barely gets driven. Does it still need servicing?
Yes. Oils and fluids are affected by elapsed time and storage conditions as well as mileage. We review the service history, time since the last service and current condition, then explain what needs attention.
Does everything have to be replaced at once?
We use the service history, elapsed time, driving conditions and current condition to decide what needs work now. For parts that can remain in use, we explain when to check them again. Flushing and additives are also recommended according to the car’s condition.
Does a new battery always need to be registered?
It depends on the model. We check the manual to see whether the car requires registration with a diagnostic tool or learns the new battery itself, then proceed accordingly.
How do you set the quote and the road test?
We explain the required work and estimate first. Road-test scope is agreed in advance, and owners concerned about collection-car mileage can request that it be omitted.
If you want your car looked after properly
We will review your service history and the condition of the car, then explain the work it needs now. Product selection and scope are discussed first, with assembly, fluid levels and operation checked after the work.
The model, year, mileage and recent service history help us prepare for your visit.
Call 031-258-1617Book on Naver031-258-1617 · NHC Motors, Suwon · By appointment