What this part does (and why it matters)
The coolant expansion tank (also called the header/overflow reservoir) is part of the engine cooling system. It provides space for coolant expansion when hot, helps de-gas the system, and supplies coolant back to the radiator as temperatures drop. A failing tank or hose can cause coolant loss, air in the system, overheating, and costly engine damage.
Condition & what’s included
You will receive the exact item shown in the photos. Please inspect all photos carefully for connectors, mounting points, hose routing and overall condition. Some units have a coolant level sensor port and bleed/return connections—match yours visually.
Item photos (high resolution)
Tip: match the shape, hose angles, and part numbers before purchase.
📍 Where this part fits in the vehicle (reference photos)
🚘 Vehicle examples (match your body style)
✅ Fitment (exact model series & years) + part numbers
This listing is for the expansion tank A2045000049 (with hose A2045010982 shown in photos). Fitment is best confirmed by matching your old part number and the photos.
| Make | Model / Series | Body style | Year range | Notes (verify before buying) |
|---|---|---|---|---|
| Mercedes-Benz | C‑Class (W204 / S204 / C204) | Saloon / Estate / Coupé | 2007–2015 | Common across many C180/C200/C220 CDI/C250/C350 variants incl. 4Matic. Match the tank shape + hose routing. |
| Mercedes-Benz | GLK‑Class (X204) | 5‑door SUV | 2008–2015 | Confirm your old tank number is A2045000049 (or related/superseded). Compare mounting points. |
| Mercedes-Benz | E‑Class (W212 / S212) | Saloon / Estate | 2009–2016 | Used on many W212/S212 cooling setups. Always verify by part number and photos. |
| Mercedes-Benz | E‑Class Coupé/Cabriolet (C207 / A207) | 2‑door Coupé / Convertible | 2009–2017 | Confirm the exact connection layout (bleed lines and hose angle can vary). |
| Mercedes-Benz | CLS‑Class (C218 / X218) | Saloon / Shooting Brake | 2011–2017 | Check part number and sensor/return port configuration on your original tank. |
❌ Will NOT fit (to avoid wrong orders)
Symptoms of a faulty expansion tank / hose
• Coolant loss / low coolant warning
• Sweet coolant smell, steam, or visible leaks around the tank seam
• Cracks near hose ports or the cap neck
• Overheating or fluctuating coolant temperature
• Air in system (gurgling) / poor heater performance
Why choose an original part over cheap copies?
Original factory parts are built to the correct tolerances, plastics, and port angles so hoses sit correctly and the system seals properly. Aftermarket copies can vary in wall thickness, sensor port fitment, and hose alignment—leading to leaks and repeat repairs. Buying quality used can save serious money vs new dealer pricing.
🛠️ Fitting instructions, tools & estimated time
Required tools
• Basic socket set (commonly 8mm/10mm)
• Torx bits (commonly T25/T30 depending on model)
• Hose clamp pliers (or suitable pliers)
• Flat screwdriver / trim tools
• Coolant catch pan + funnel
• Gloves + safety glasses
Estimated repair time
DIY: 45–90 minutes (vehicle dependent).
Workshop: usually 0.8–1.5 labour hours depending on access and bleed procedure.
Step-by-step overview (coolant system safety first)
1) Let engine cool fully. Never open the cap hot (pressurised system).
2) Depressurise. Slowly loosen the cap when cold.
3) Capture coolant. Place a pan under the vehicle; drain enough coolant to drop the level below the tank ports.
4) Remove connections. Release hose clamps, disconnect hoses, and unplug the coolant level sensor (if fitted).
5) Unbolt tank. Remove mounting bolts/clips and lift the tank out carefully.
6) Transfer parts. Move any sensor/clip/cap only if compatible and in good condition (otherwise replace).
7) Install replacement. Fit tank, reconnect hoses exactly as original, and secure clamps.
8) Refill & bleed. Refill with the correct coolant mix and bleed air as per your model procedure.
9) Leak check. Run to temperature, check level after cooling, re-top up if needed.
Coolant is toxic—dispose of old coolant responsibly. If you’re not confident, message us about our fitting service (subject to availability).
Garage Labour Cost Estimator (no scripts)
Use this quick formula: Labour cost (£) = hourly rate × labour hours
| Example hourly rate | 0.8 hr | 1.0 hr | 1.5 hr | 2.0 hr |
|---|---|---|---|---|
| £60/hr | £48 | £60 | £90 | £120 |
| £80/hr | £64 | £80 | £120 | £160 |
| £100/hr | £80 | £100 | £150 | £200 |
| £120/hr | £96 | £120 | £180 | £240 |
Want us to fit it? We offer a fitting/repair service (subject to availability) — message via eBay for a quote.
🌍 Postage, Worldwide Delivery & Collection
Worldwide delivery
We ship worldwide through eBay’s Global Shipping / international delivery options where available. Tracking and import charges are shown at checkout.
Important: Buyers must ensure the checkout delivery address is correct — once paid we cannot change address details.
Collection (7 days a week, till 8pm)
Collection available by appointment (including bank holidays by prior arrangement).
ThePartCaptain • Unit 8–11 (located after Bee Kwik Scaffolding)
Ivanhoe Business Park, Wortley Road (sometimes shown as Wortley Road for this postcode)
Rotherham, S61 1LZ
Eligible countries (eBay international programme list)
Destinations can vary by item/category and eBay rules, but the standard eligible country list includes the following:
📦 Stock, repairs & why buy from ThePartCaptain
