978961 O-Ring | Genuine Volvo Penta Part

🔧 Product Description

Genuine Volvo Penta o-ring for the later version of the cylinder block, the one machined with an o-ring groove, weighing 0.002 kg and listed for 23 applications across D engines. It supersedes 975138. The block version is what decides it — an earlier block without the groove has nothing for this ring to sit in.

🚤 Compatibility

• Engine Family: D

Full model list at the end of this description.

⚙️ Key Features

• For the later cylinder block with the o-ring groove
• Fits 23 applications across D engines
• 0.002 kg
• Supersedes 975138
• Also supersedes Volvo part numbers 840494, 840562, 840977, 840978, 858498, 858783, 858791, 876036, 876202 and 876203

🔌 Function

Seals a joint on the cylinder block by squashing into its machined groove, the trapped ring closing the gap under compression.

⚠️ Common Signs of Failure

• Seeping or dripping at the joint the ring seals
• Ring found flattened, nipped or twisted on strip-down
• Rubber gone hard, glazed or crazed
• Ring nibbled or extruded at the groove edge
• Groove itself scored or corroded

🛠️ Service Notes

• Check the block for the o-ring groove before ordering — this ring is only for the later machined version
• O-rings are single-use; never refit one that has been compressed

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 978961 → Supersedes 975138 → Supersedes 858784

OEM / Related Numbers

• 975138 earlier number superseded by this part

📦 Condition

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

🔎 Full Model Compatibility

Typically suits:

• Volvo Penta 2003, 2003R, 2003R SOLAS, 2003TB, 2003TB SOLAS, 2001AG, 2001B, 2001BG, 2001D, 2003D, 2003T, 2003TR, 2002AG, 2002B, 2002BG, 2002D, 2003B, 2003B SOLAS, 2003 SOLAS, 2001, 2002, 2001R
• Volvo Penta D2003AG