1. Start with the OEM number

The listing identifies the part as a crankshaft seal with OEM NO 90311-45003, made in China. Matching the OEM reference is the most direct way to narrow the selection. The supplier lists several related parts with different references and sizes:

These are separate parts, not alternatives for one another. If your application calls for 21421-2B020, for example, 90311-45003 is not the right choice just because both are crankshaft seals.

2. Check the dimensions against the part you are replacing

The 90311-45003 listing gives a size of **45629**. It does not state the unit or the order of the three figures. Before you place a volume order, confirm with the supplier which figure is the shaft (inner) diameter, which is the housing (outer) diameter and which is the width, and check them against the original seal or your engine documentation. A sample order is offered, and it lets you check the fit physically.

3. Medium and operating conditions: what the listing does not cover

The fluid being sealed, the operating temperature and the shaft speed all affect whether a seal is suitable. The 90311-45003 listing does not publish the rubber compound, the sealed medium, the temperature range or a speed rating. None of the other listings in the table publish these either.

The supplier's separate general "Oil Seals" listing gives working temperatures for rubber RP (-35 to +120°C) and fluorine rubber FKM (-20 to +200°C), with hydraulic oil, emulsion and water as working media. Those figures belong to that general listing. Do not assume they apply to 90311-45003. Ask the supplier to confirm in writing:

• the lip and body material of the seal;
• whether it is suited to the engine oil and the temperatures in your application;
• whether it is a front or rear position part, and which vehicle or engine models it fits.

If the supplier cannot confirm these details, this recommendation does not apply to your application.

4. Pricing and order terms

The listings do not include a published oil seal price. The supplier says it quotes based on your request and asks buyers to provide the part number, machine model, quantity and size. The 90311-45003 listing gives these terms:

• Minimum order quantity: 100 pieces
• Payment terms: L/C, D/A, D/P, PayPal, Western Union, T/T
• Packaging: standard box, neutral box or the customer's own box
• Lead time: 5–7 days in stock, or 30 days if out of stock (delivery time is given as 5–30 days)
• Shipment: express, air or sea, from Chinese ports including Guangzhou, Shenzhen, Shanghai, Ningbo and Qingdao

Treat these as listed terms and confirm them for your specific order.

5. Custom and OEM/ODM requirements

If none of the listed references matches your part, the supplier lists OEM/ODM processing, sample orders, development of auto spare parts from samples provided by customers, and technical support for customer requirements. Provide a drawing or sample along with the dimensions and application details.

Selection checklist

1. Match the OEM number (for example, 90311-45003) to your application.
2. Confirm the meaning and units of the listed size 45629 against the original part.
3. Get written confirmation of the material, sealed medium, temperature and position.
4. Confirm vehicle or engine fitment.
5. Plan around the 100-piece MOQ and ask for a quote with your quantity.
6. Consider ordering a sample before you place a volume order.