# 20405578 O-Ring | Genuine Volvo Penta Part

🔧 Product Description

  

Genuine Volvo Penta Oil Cooler Core O-Ring - Part Number: 20405578

  

Genuine Volvo Penta O-ring sealing the oil-cooler core or housing interface. Two are used in the common TAD530-TAD733 oil-cooler assembly, while selected early/late TD520 and TD720 housings use one according to the serial-number-specific layout.

  

⚙️ Key Features

  

• Oil- and coolant-resistant cooler O-ring

• Two used in the common oil-cooler assembly

• One used in selected TD520/TD720 serial-specific housings

• Works with oil cooler 20797236 and bushing 20405758

• Should be renewed whenever the cooler housing is dismantled

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 20405578 - current Volvo Penta oil-cooler O-ring reference

  

OEM / Related Numbers:

  

• 20797236 - oil cooler

• 20405758 - cooler bushing

• 20405752 - retaining screws

• 20405569 - companion sealing rings

• 20405747 - housing gasket

  

Aftermarket / Verified Equivalents:

  

• No aftermarket equivalent

  

🚤 Compatibility

  

Commonly used on:

  

• Volvo Penta D5/D7 oil-cooler and oil-filter housings

  

Typically suits:

  

• Engine / equipment models:

• TD520GE

• TAD530GE

• TAD531GE

• TAD532GE

• TD720GE

• TAD730GE

• TAD731GE

• TAD732GE

• TAD733GE

  

• Engine Type: Volvo Penta 5- and 7-litre industrial diesel

• Year / Serial Range: Oil-cooler housing and serial-number dependent; TD520/TD720 designs change at serial 5301099356/5301099357

  

🔌 Function

  

Seals the oil-cooler core or housing so engine oil and coolant remain in their separate passages.

  

Common signs of failure:

  

• Oil in the coolant

• Coolant contamination in the engine oil

• External leakage at the cooler housing

• O-ring flattening, cuts or hardening

• Repeated leakage after cooler service

  

📦 Condition

  

• Genuine Volvo Penta part

• Brand new

• Supplied in original or equivalent packaging

## Details

- **Price:** 9.45 AUD
- **Vendor:** Volvo Penta
- **Tags:** Volvo Penta

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 9.45 AUD | In stock |

## Images

- 20405578 O-Ring | Genuine Volvo Penta Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/20405578-o-ring-genuine-volvo-penta)
> Updated: 2026-07-30