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Smart Fortwo Fluids Quick-Ref Card — Glove Box Printable

Easy 2 min reference Smart Fortwo 450Smart Fortwo 451Smart Roadster 452Smart Fortwo 453Smart Forfour 453

What this is + why it matters

Print this page, fold it once, and keep it in the glove box. It is the short version of the Fluids and Specs Reference — every fluid on every Smart chassis, on one page.

You will need it more often than you think. At a parts counter on a Saturday morning, you do not want to be trying to remember whether your 453 takes Mercedes-spec or Renault-spec oil. In a shop you have never used before, you want to be able to point at the right spec on the page when the service writer says "we will use our normal 5W-30." Smart crosses two manufacturers — Mercedes-spec on 450, 451, 452 and Renault-spec on 453 — and that one fact is behind most of the wrong-fluid mistakes owners make.

This card is a memory aid. The workshop manual for your year is still the final word.

What you'll need

Engine oil

Chassis Spec Capacity (with filter) Interval
450 petrol (0.6 / 0.7L) 5W-40 ACEA A3/B4 ~3.0L 10,000 mi / annual
450 CDI (0.8L diesel) 5W-40 low-SAPS, MB 229.31 or 229.51 ~3.5L 10,000 mi / annual
451 NA (M132 1.0L petrol) 5W-30 ACEA C3, MB 229.51 ~3.4L 10,000 mi / annual
451 Brabus (turbo petrol) 5W-30 ACEA C3, MB 229.51 ~3.4L 6,000 mi / annual
451 CDI (diesel) 5W-30 low-SAPS, MB 229.51 ~3.7L 6,000 mi / annual
451 MHD (micro-hybrid petrol) 5W-30 ACEA C3, MB 229.51 ~3.4L 10,000 mi / annual
452 Roadster 5W-40 ACEA A3/B4 ~3.0L 10,000 mi / annual
453 NA (B4D 1.0L) 5W-30 Renault RN0700 ~3.5L 10,000 mi / annual
453 turbo (H4Bt 0.9L) 5W-30 Renault RN0710 ~3.5L 6,000 mi / annual
453 EQ (electric) n/a — no engine oil n/a n/a

Brake fluid

Chassis Spec Capacity (full flush) Interval
450 / 451 / 452 DOT 4 ~0.5L Every 2 years
453 (Fortwo / Forfour) DOT 4 LV (low viscosity) ~0.5L Every 2 years
453 EQ DOT 4 LV ~0.5L Every 2 years

Coolant

Chassis Spec Capacity Interval
450 / 451 / 452 Mercedes blue, MB 325.x / 326.0 (silicate-based) ~4-5L 5 years / 60k mi
453 Fortwo / Forfour Renault Type D (organic, OAT) ~4-5L 5 years / 60k mi
453 EQ Renault Type D + EQ-spec battery coolant (separate loop) varies Per workshop manual

Washer fluid

Chassis Spec Capacity
All Smart Fortwo / Forfour / Roadster Methanol-free formula, mix per climate ~2L

AC refrigerant

Chassis Refrigerant Charge Notes
450 / 451 / 452 R134a ~450-500g (verify under-hood label) Original spec
453 (early, ~2015–2017) R134a per under-hood label Verify by year
453 (later, ~2017+) R1234yf per under-hood label Switch year varies by region
453 EQ R1234yf per under-hood label Heat-pump-equipped variants vary

Manual transmission and DCT fluid

Chassis Spec Capacity Interval
451 automated manual (5-speed) Sealed — no service n/a Adaptation / teach-in only
452 manual Mercedes-spec gear oil (verify in manual) ~1.4L Per workshop manual
453 manual (5-speed) Renault-spec gear oil ~1.5-2L Per workshop manual
453 DCT (twinamic 6-speed) Getrag DCT-spec fluid ~5-6L per service 30,000 mi (Star Diagnosis fill-level)

How to use this card

  1. Confirm your chassis first. Pull your VIN and decode it if you are unsure. The Mercedes-Smart cars (450 / 451 / 452) and the Renault-Smart cars (453, including Forfour 453) take fundamentally different oil and coolant.
  2. Spec column is non-negotiable. Capacity column is a starting point. Fill to about 0.3L below the listed capacity, run the engine, then check the dipstick or sight glass and top off.
  3. Year-edge cases (453 R134a vs R1234yf, 451 CDI emissions revisions) need verification. When the under-hood label disagrees with this card, the label wins.
  4. At the parts counter, show the spec, not the brand. "MB 229.51 5W-30" or "Renault RN0710 5W-30" is the correct ask. Do not let anyone substitute "our normal 5W-30."
  5. For a flush — not just a top-off — use the Fluids and Specs Reference or the workshop manual. A flush is the case where the wrong spec actually does damage.

Common gotchas

  • MB 229.51 vs Renault RN0700 / RN0710 are NOT interchangeable. A 451 wants MB-approval. A 453 wants Renault-approval. Walking out of the parts shop with the wrong one is the single most common Smart oil mistake.
  • DOT 4 LV is not generic DOT 4. The 453 brake reservoir cap explicitly calls for low viscosity. Generic DOT 4 will technically work, but ESP / ABS calibration is built around LV viscosity. Use what the cap says.
  • R134a vs R1234yf split mid-453 production. Around 2017, regulators forced the switch to R1234yf in many markets. The under-hood AC label is the only reliable source for your specific car. Charging R134a into an R1234yf system (or vice versa) damages the system and is illegal in some jurisdictions.
  • DCT fluid is NOT engine oil. The 453 twinamic DCT takes a Getrag dual-clutch-specific fluid. A few owners (and a few quick-lube shops) have topped DCT off with engine oil and destroyed the unit. Service requires Star Diagnosis to set fill level — it is not a drain-and-fill in the driveway.
  • Coolant chemistry by chassis: 450 / 451 / 452 take silicate-based Mercedes blue (MB 325.x / 326.0). 453 takes organic-acid Renault Type D. They look similar and they will mix in a tank, but mixing them gels the inhibitor package and corrodes water-pump seals. Flush, do not mix.
  • CDI oil is low-SAPS, not "regular" 5W-40 or 5W-30. Diesel particulate filters and EGR systems hate the high-ash content of generic petrol oil. Always check for the low-SAPS marking on the bottle.

When to skip DIY

This card is for top-offs and confirming a parts-counter purchase. Anything more — a flush, a system that has been opened, a fluid that has been mixed, a transmission service on the 453 DCT, an AC recharge — needs the Fluids and Specs Reference at minimum and the workshop manual for your year for anything load-bearing.

The cost of being wrong on a top-off is small. The cost of being wrong on a flush, a refrigerant charge, or a DCT service is the price of the part you damaged. When the cost of being wrong is high, the workshop manual wins over any quick reference, this one included.

Manual references

Top reference manuals for this chassis (from our catalog of 88 Smart manuals):

Need something specific? Browse all 88 manuals by chassis, year, region, or document type.

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