# 21100405 Valve Seat | Genuine Volvo Penta Part

## 🔧 Product Description

A genuine Volvo Penta lubricating-oil pressure-control valve seat used inside the TAD650VE/TAD660VE oil cooler and oil-filter housing. This is not a cylinder-head valve seat. It forms the precision sealing surface for control plunger 20862028, allowing the spring-loaded valve to regulate or bypass oil flow according to system pressure.

## 🚤 Compatibility

Typically suits:

-   Volvo Penta TAD650VE
-   Volvo Penta TAD660VE

-   **Engine Family:** TAD

## ⚙️ Key Features

-   Precision oil-control valve seat for the cooler/filter housing
-   Machined sealing face mates with control plunger 20862028
-   Controls internal oil bypass or pressure-regulation flow
-   Hardened surface resists repeated plunger contact and oil-borne particles
-   Requires a clean, undamaged housing bore for correct seating
-   Engine type: Inline-six industrial diesel lubricating-oil system

## 🔌 Function

Provides the accurately located sealing surface for the oil-pressure control plunger. Together with the spring and sleeve, it directs oil through the correct cooler, filter or bypass path as operating pressure changes.

## ⚠️ Common Signs of Failure

-   Oil-pressure warning at hot idle
-   Scoring or pitting on the seat face
-   Valve plunger sticking open because of debris
-   Abnormal oil-filter bypass or cooler-flow behaviour

## 🛠️ Service Notes

-   Seat inserts are an interference fit in the head, so the counterbore has to be clean, round, flat and square before a new seat goes in; normal practice is to chill the insert and warm the head so it drops into place rather than forcing it
-   This is machine-shop work — the seat must be cut concentric with the valve guide after installation, so check or renew the guides at the same time and cut the seat angles once the insert is secure
-   Inspect the head casting for cracks and for a pounded or spread counterbore before committing to a new seat; a seat that has come loose has usually damaged its pocket
-   Use the interference fit, insert size and seat angles specified for your engine rather than any general figure, as they differ between heads
-   Check each valve on its finished seat for an even contact band right the way round, and confirm valve position and any permitted recession against the workshop manual for your engine

## 🔄 Supersession & Cross Reference

### OEM / Related Numbers

-   20862028 - oil-control plunger
-   21100407 - calibrated return spring
-   21100410 - control sleeve
-   21099784 - oil cooler/filter housing assembly

### Other-Brand OEM Numbers

-   VOE21100405

## 📦 Condition

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

## Details

- **Price:** 133.86 AUD
- **Vendor:** Volvo Penta
- **Type:** Oil & Lubrication
- **Tags:** Volvo Penta

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 133.86 AUD | In stock |

## Images

- 21100405 Valve Seat | Genuine Volvo Penta Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/21100405-valve-seat-genuine-volvo-penta)
> Updated: 2026-10-10