16221 Hollow Screw | Genuine Volvo Penta Part

🔧 Product Description

Genuine Volvo Penta hollow screw, part number 16221, for the TWD1683VE engine. This drilled fastener secures a fluid line fitting to its port while allowing oil or fuel to pass through its centre, making it both a mounting bolt and part of the flow path. Supplied as a single screw with a net weight of 0.088 kg.

🚤 Compatibility

Typically suits:

• Volvo Penta TWD1683VE

• Engine Family: TWD

⚙️ Key Features

• OEM Volvo Penta part number 16221
• Hollow (drilled) screw design allowing fluid to pass through the fastener
• Net weight 0.088 kg
• Fits the TWD1683VE engine
• Supplied as an individual screw
• Engine type: Volvo Penta 16-litre industrial diesel

🔌 Function

A hollow screw clamps a fluid line or banjo fitting against its port while its internal drilling carries oil or fuel through to the connected component. It therefore serves as both the mechanical fastener and part of the sealed flow passage.

⚠️ Common Signs of Failure

• Persistent weeping or dripping at the fitting even after retorquing
• Damaged, rounded or seized hex head preventing correct tightening
• Stripped, corroded or cross-threaded threads causing loss of clamping force
• Blocked or restricted internal passage reducing oil or fuel delivery
• Cracking or stretching of the screw after over-tightening, leading to pressure loss

🛠️ Service Notes

• Check the through-passage is clear and clean before fitting; a blocked hollow screw starves whatever it feeds
• Always fit new sealing washers, one each side of the union where the original had them, and never reuse a crushed washer
• Hold the fitting or pipe end against turning as you tighten, so the line is not twisted and the union is not pulled out of position
• Tighten to the figure in the workshop manual for your engine — these seal by crushing the washer, not by force, and over-tightening splits the head or shears the shank
• Bring the system up to working pressure and check for weeps before closing the space up

🔄 Supersession & Cross Reference

OEM / Related Numbers

• 991046 - related hollow screw used elsewhere in the cooling arrangement
• 23177941 - related water pipe

📦 Condition

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