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Details
| Specification | Value |
|---|---|
| Brand | MAHLE |
| MPN | crt21000s |
| Category | coolant expansion tank |
| Length [mm] | 188.0 mm |
| Width [mm] | 172 mm |
| Height [mm] | 167.0 mm |
| Additionally required articles (article numbers) | CRB 96 000S |
| Additionally required articles (article numbers) | CRB 146 000S |
| Packaging length [cm] | 18.0 cm |
| Packaging width [cm] | 18.00 cm |
| Packaging height [cm] | 16.00 cm |
| Net Weight [g] | 424 g |
OE numbers (8)
Search by this OE number to find compatible parts
- AUDI / VW / CUPRA—5Q0 121 407 A
- AUDI / SEAT / SKODA / VW—5Q0 121 407AA
- AUDI—5Q0121407D
- AUDI / VW—5Q0121407F
- AUDI / CUPRA / SEAT / SKODA / VW—5Q0121407G
- AUDI / SEAT / SKODA / VW—5Q0121407M
- AUDI—5Q0121407S
- AUDI / SEAT / SKODA / VW—5Q0121407T
Where this part fits
Original-fit position for OE 5Q0121407AA. The red ring marks where this part installs on the vehicle.
About this product
The MAHLE coolant expansion tank (CRT 21 000S) is a professional-grade replacement component engineered for long service life and reliable operation across all conditions your vehicle encounters. The part is built to the following specification: Length [mm]: 188, 0 mm, Width [mm]: 172 mm, Height [mm]: 167, 0 mm, Colour: Steel, Material: Plastic. Each dimension is checked against the OEM reference to ensure the component seats and functions correctly first time. Verified to fit AUDI, SEAT, SKODA, VW models. All compatibility data is cross-checked against the TecDoc database — select your vehicle to confirm the part matches your specific engine and year. This part supersedes original equipment references: 043023N, 100 223 0011, 103446, 1114703000 and 15 more. Matching these numbers confirms a like-for-like replacement with no loss of function. MAHLE is a recognised supplier of automotive replacement components to independent workshops and dealer networks across Europe. All parts are sourced from authorised distribution channels and carry full manufacturer traceability — you receive exactly the same component supplied to professional garages and dealer workshops. If fitment or specifications do not match your vehicle, our technical team can help identify the correct alternative — use the vehicle selector or contact us with your VIN for a guaranteed-fit recommendation. Replacing worn components on schedule preserves your vehicle's safety, reliability, and resale value — and aftermarket parts from established brands deliver OEM-equivalent performance at a fraction of the dealer price. Every part is dispatched with tracked delivery and a 14-day money-back guarantee with hassle-free returns.
About MAHLE
MAHLE, founded in 1920 in Stuttgart, Germany, is a global leader in engine components and filtration systems. MAHLE specialises in pistons, cylinder liners, gaskets, turbocharger components, oil filters, air filters, and fuel filters. As an OE supplier to nearly every car and truck manufacturer worldwide, MAHLE products are engineered to exact factory specifications. Trusted by professional workshops and racing teams alike, MAHLE delivers outstanding engine performance and filtration efficiency across millions of applications.
Suitable cars
Equivalent products (10)
coolant expansion tank MAHLE CRT 21 000S — compatible car models
| Car models | AUDI: A3 (8V1, 8VK), A3 Convertible (8V7, 8VE), A3 Limousine (8VS, 8VM), A3 Sportback (8VA, 8VF), Q2 (GAB, GAG), Q3 (F3B), Q3 Sportback (F3N), TT (FV3, FVP), TT Roadster (FV9, FVR); SEAT: ATECA (KH7, KHP), LEON (5F1), LEON Hatchback Van (5F1), LEON SC (5F5), LEON ST (5F8); SKODA: KODIAQ I (NS6, NS7, NV7), OCTAVIA III (5E3, NL3, NR3), OCTAVIA III Combi (5E5, 5E6), OCTAVIA IV Combi (NX5, PV5), SUPERB III (3V3), SUPERB III Estate (3V5), YETI (5L); VW: GOLF ALLTRACK VII Variant (BA5, BV5), GOLF SPORTSVAN VII (AM1, AN1), GOLF VAN VII Variant (BA5), GOLF VII (5G1, BQ1, BE1, BE2), GOLF VII Van (5G1), GOLF VII Variant (BA5, BV5), PASSAT ALLTRACK B8 Variant (3G5, CB5), PASSAT B8 (3G2, CB2), PASSAT B8 Variant (3G5, CB5) |
|---|---|
| Engines | 1.0 TFSI; 1.4 TFSI; 1.6 TDI; 35 TDI; 1.8 TFSI; 1.0 TSI; 1.2 TSI; 1.4 TSI; 2.0 TDI; 1.6 TDI 4motion; 1.2 TSi; 1.4 TSI 4motion; 1.4 GTE Hybrid |
| Year of manufacture | 2009-2024 |
| Manufacturer article number (MPN) | CRT 21 000S |
| OE part numbers | 5Q0 121 407 A, 5Q0 121 407AA, 5Q0121407D, 5Q0121407F, 5Q0121407G, 5Q0121407M, 5Q0121407S, 5Q0121407T |
Compatibility check
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Please wait while we load vehicle compatibility information.Description and what's included
MAHLE crt21000s BEHR. Additionally required articles (article numbers): CRB 146 000S. Additionally required articles (article numbers): CRB 96 000S. Colour: 1. Height [mm]: 167,0 mm. Length [mm]: 188,0 mm. Material: 6. Net Weight [g]: 424 g. Packaging height [cm]: 16,00 cm
- 1x coolant expansion tank
Shipping, returns, warranty
Free UK delivery on orders over £99.00. Tracked standard shipping.
- Standard delivery: 5–9 business days
- Order before 5pm — ships the next working day
- Free returns within 14 days
- All parts backed by manufacturer warranty
Warranty: 12-month manufacturer warranty on all parts. 14-day money-back guarantee if the part doesn't fit your vehicle.
Frequently Asked Questions
Is this coolant expansion tank compatible with my car?
This coolant expansion tank fits AUDI, SEAT, SKODA, VW vehicles. Use the vehicle selector at the top of the page to check exact compatibility — enter your car's make, model, and engine for a confirmed fitment match. All fitment data is verified through TecDoc.
What specifications does this MAHLE coolant expansion tank have?
This MAHLE coolant expansion tank has the following specifications: Length [mm]: 188,0 mm; Width [mm]: 172 mm; Height [mm]: 167,0 mm; Colour: 1; Material: 6; Supplementary Article/Supplementary Info: 897. Check the full specifications table above for complete details.
What OE part numbers does this coolant expansion tank replace?
This coolant expansion tank replaces OE part numbers: 5Q0 121 407 A, 5Q0 121 407AA, 5Q0121407D, 5Q0121407F, 5Q0121407G, 5Q0121407M, 5Q0121407S, 5Q0121407T. Cross-reference these numbers with your vehicle's original part number to confirm compatibility.
How much does a coolant expansion tank cost?
This MAHLE coolant expansion tank is available for £22.99. Coolant expansion tank prices vary depending on brand, specifications, and vehicle compatibility. MAHLE parts offer a balance of quality and value, backed by our 14-day money-back guarantee.
How do I know when to replace my coolant expansion tank?
Regular inspection of your coolant expansion tank is recommended as part of routine vehicle maintenance. Watch for changes in performance, unusual noises, or visual signs of wear. Consult your vehicle's owner manual for manufacturer-recommended replacement intervals specific to your make and model.
What tools do I need to replace a coolant expansion tank?
Tools needed: hose clamp pliers, flat-head screwdriver, 8mm socket, coolant top-up bottle. Difficulty: Easy DIY. Safety warning: Only open the expansion tank cap when the engine is completely cold -- coolant system is under pressure when hot and will spray scalding fluid if opened.
Can I use this part as a replacement for OE 5Q0 121 407 A?
Yes, this MAHLE coolant expansion tank is a direct replacement for OE part number 5Q0 121 407 A. It is manufactured to meet or exceed original equipment specifications, ensuring proper fitment and performance. All cross-reference data is verified through TecDoc.
Related categories
Common OE numbers for this part
Common original equipment numbers linked to stocked alternatives.
