20405578 O-Ring | Genuine Volvo Penta Part

🔧 Product Description

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.

🚤 Compatibility

• Engine Family: D, TD, TAD, MD

Full model list at the end of this description.

⚙️ 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
• Engine type: Volvo Penta 5- and 7-litre industrial diesel
• Quantity varies by assembly, most commonly two

🔌 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

🛠️ Service Notes

• Always fit a new O-ring — never refit one that has been removed, as it has already taken a set in its groove
• Clean the groove and both sealing faces and check them for nicks, scoring and corrosion pitting; a damaged groove will leak however good the new seal is
• Smear the ring with a little clean lubricant compatible with the fluid it seals, then roll it into place by hand so it sits untwisted and fully in its groove
• Never lever an O-ring over a sharp edge or thread with a screwdriver; use a blunt plastic tool and protect any edge the ring has to pass
• Assemble the joint squarely and tighten to the figure and sequence given in the workshop manual for your engine — over-tightening extrudes the ring and causes the very leak you were curing

🔄 Supersession & Cross Reference

OEM / Related Numbers

• 20797236 - oil cooler
• 20405758 - cooler bushing
• 20405752 - retaining screws
• 20405569 - companion sealing rings
• 20405747 - housing gasket

📦 Condition

• Genuine Volvo Penta part
• Brand new
• Supplied in original or equivalent packaging

🔎 Full Model Compatibility

Typically suits:

• Volvo Penta D7A-B TA, D7A-T, D7A-TA, D7C-B TA, D7C-TA
• Volvo Penta D5A-B TA, D5A-T, D5A-TA
• Volvo Penta MD2010, MD2010B
• Volvo Penta TAD520GE, TAD520VE
• Volvo Penta TAD530GE MECH, TAD530GE EDC4
• Volvo Penta TAD531GE MECH, TAD531GE EDC4
• Volvo Penta TAD720GE, TAD720VE
• Volvo Penta TAD721GE, TAD721VE
• Volvo Penta TAD722GE, TAD722VE
• Volvo Penta TAD730GE MECH, TAD730GE EDC4
• Volvo Penta TAD731GE MECH, TAD731GE EDC4
• Volvo Penta TAD750GE, TAD750VE
• Volvo Penta TD520GE, TD520VE
• Volvo Penta TD720GE, TD720VE PP
• Volvo Penta TAD532GE EDC4
• Volvo Penta TAD550GE
• Volvo Penta TAD551GE
• Volvo Penta TAD650VE
• Volvo Penta TAD660VE
• Volvo Penta TAD732GE EDC4
• Volvo Penta TAD733GE EDC4
• Volvo Penta TAD751GE
• Volvo Penta TAD760VE