An original-equipment (OEM) catalytic converter and an aftermarket replacement can look identical underneath a car, but they are built to different platinum (Pt, 78), palladium (Pd, 46) and rhodium (Rh, 45) loadings, which is why buyers price them differently. Markings, construction and a stamped code answer the identification question, and an identified OEM unit typically scraps for 3 to 5 times more than an aftermarket one.
What Is the Difference Between an OEM and an Aftermarket Catalytic Converter?#
An OEM catalytic converter must meet its vehicle's full regulatory useful life, 120,000 miles or 11 years under US Tier 2 and 150,000 miles or 15 years under Tier 3, per 40 CFR Part 86, while an aftermarket replacement is certified to a lower, separate standard. That gap is why the two units differ in platinum, palladium and rhodium content even on the same application: an aftermarket part only clears its own lower standard, built to the minimum PGM loading that passes it. Both fall under the wider category of scrap platinum, palladium and rhodium, and the signals below decide which class, and which value tier, a specific converter falls into.
Why the Value Gap Is Regulatory, Not Cosmetic#
The commonly quoted 8 years/80,000 miles is the Clean Air Act §207(i) emissions-warranty period, not the useful-life durability requirement, and confusing the two understates how much more metal an OEM unit is built to carry. A warranty only obligates a repair; a useful-life certification obligates the part to keep working for the longer span above, which is why OEM units carry more PGM. How much platinum, palladium and rhodium is in a catalytic converter breaks that gram-level gap down by fuel type and era.
How to Tell If a Catalytic Converter Is OEM or Aftermarket#
A converter's markings, brand name, compliance text and construction identify it as OEM or aftermarket, four signals a seller can check without a parts manual.
Markings, Brand Names and Compliance Text#
OEM converters carry a stamped serial or part number and the vehicle maker's or a tier-1 supplier's name, such as Denso, Bosch or Eberspächer. Aftermarket units are typically labeled "universal," "direct fit" or "CARB compliant" under brands such as MagnaFlow or Walker, with no matching code. The table below lines up five signals side by side.
| Signal | OEM | Aftermarket |
|---|---|---|
| Markings | Stamped serial or part number, vehicle-matched | Generic label, barcode, or no matching code |
| Brand name | Vehicle maker or tier-1 supplier (Denso, Bosch, Eberspächer) | Aftermarket brand (MagnaFlow, Walker, Bosal) |
| Compliance text | Vehicle-specific fitment | "Universal," "Direct Fit," "CARB Compliant," "49-state," "50-state" |
| Construction | Heavier shielding, factory weld finish | Lighter, clamp-on or recently welded |
| Appearance | Aged, matched to the vehicle's mileage | Cleaner, newer, generic housing |
Source: RRCats, "OEM vs Aftermarket Catalytic Converters"; ScrapMonster, Converter Identification Guide 2026.
Construction and Appearance Signals#
OEM units generally show heavier shielding and a factory weld finish; aftermarket units are lighter, simpler and often clamp-on or newly welded, built only to clear the lower aftermarket standard. Appearance, aged versus clean and generic, is a fast first check but not a substitute for reading the stamped code covered next.
Reading a Converter's Serial Number or Code#
A converter code identifies the part, not its metal content: no manufacturer publishes a code-to-grams table, so every published figure is a sampled average, not a specification. Reading catalytic converter codes and serial numbers is a related skill; a code matching a known database entry confirms what the markings already suggest.
Manufacturer Code Formats#
Converter codes follow manufacturer-specific formats: General Motors uses an 8 to 10 digit number, Ford an alphanumeric code with hyphens, and Honda/Acura an "18160-" prefix, never "37820-," which marks the engine control module, not a converter. Toyota and Lexus units carry two 5-digit number groups, often marked Denso or Toyota; BMW, Mercedes and Audi formats vary and show a supplier logo instead. The table below gives one representative code per manufacturer.
| Manufacturer | Code format | Example | Typical location |
|---|---|---|---|
| General Motors | 8 to 10 digit numeric | 12672145 | Circular end cap |
| Ford | Alphanumeric with hyphens | 8A8Z-5G232-C | Heat shield or body |
| Honda / Acura | 18160- prefix plus alphanumeric suffix | 18160-RCA-A01 | Main body or end flange |
| Toyota / Lexus | Two 5-digit number groups | 17101-31130 | Body |
| BMW / Mercedes / Audi | Variable, supplier logo | Not standardized | Variable |
Source: ScrapMonster, Converter Identification Guide 2026, 7 January 2026.
What a Code Does Not Tell You#
Two units sharing the same code can assay differently, because every commercial database, including the open ConverterDatabase.com (over 5,030 sampled units), reports a statistical average, not a guarantee. Buyer-operated platforms such as Ecotrade, PMR, RRCats and ScrapMonster price against the same kind of average, and SFA (Oxford) sells a licensed report; none is authoritative like a factory spec. A buyer's own catalytic converter grades sorts codes into tiers, and catalytic converter codes and serial numbers narrows a unit only to its manufacturer family, not to a guaranteed gram count.
OEM vs Aftermarket Scrap Value#
An identifiable OEM converter is typically worth 3 to 5 times more than an aftermarket unit of the same application, RRCats reports, because it carries a known, higher PGM loading a buyer can price with confidence. How much is a catalytic converter worth sets that identified value against typical dollar ranges by type, age and condition.
Why Buyers Discount Aftermarket and Unidentifiable Units#
ScrapMonster puts a typical aftermarket converter at around $20 against $100 to $800-plus for an OEM unit, a gap both ScrapMonster and RRCats trace to lower certified loading, not condition. A buyer paying by the unit prices an unidentifiable converter at the pessimistic end of that range until an assay proves otherwise. WPIC still counts aftermarket replacements as adding roughly 15% to total recovered catalyst volumes, even though each unit is worth little on its own, a gap most pronounced in the units covered on most valuable catalytic converters.
| Metric | Aftermarket | OEM | Source |
|---|---|---|---|
| Typical scrap value | About $20 | $100 to $800 or more | ScrapMonster |
| Value multiple vs OEM | 1x (baseline) | 3 to 5 times aftermarket, or more | RRCats |
| Share added to total recycling volume | About 15% of total recovered catalyst volumes (additive, not a per-unit value) | Not applicable | WPIC, 20 August 2025 |
Sell an Identified Converter#
Once a converter is identified as OEM or aftermarket, its next step is a scrap quote, not a database lookup alone, since only an actual assay fixes the number a database average can only estimate.
Get a Quote Once You Know What You Have#
A buyer prices an identified converter against its metal content and today's PGM prices, not its code alone. The catalytic converter PGM value calculator gives a rough figure before assay, and comparing catalytic converter buyers and recyclers confirms who pays the most for a specific code and condition.
Related Converter Scrap Guides#
Related guides extend identification into recycling, pricing, assay and theft.
- Catalytic converter recycling: the decanning-to-refined-metal process after a sale.
- Catalytic converter scrap prices: the value chain from contained metal to a seller's check.
- Catalytic converter assay: the XRF, ICP and fire assay methods that replace a code estimate.
- Diesel catalytic converter and DPF scrap value: how DOC, DPF, LNT and SCR content compares.
- Catalytic converter theft: why the same OEM premium that rewards sellers also drives theft.
Identification FAQ#
How to tell if a catalytic converter is aftermarket or not?#
A converter is aftermarket if it is labeled "universal," "direct fit" or a non-OEM brand name and lacks a factory-stamped part number. An OEM unit instead carries the vehicle maker's or a tier-1 supplier's name alongside a vehicle-specific stamped code.
Is an OEM catalytic converter worth more to scrap?#
Yes. RRCats reports OEM converters are "usually worth much more, sometimes 3-5x more" than aftermarket units of the same application, because the OEM unit carries a known, higher PGM loading.
Does a converter's code tell you its platinum, palladium and rhodium content?#
No. A code identifies the part, not its assay; buyers price against a sampled average for that code, not a guaranteed figure, so two units sharing a code can still differ once tested.