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Worcester Bosch Unisilkon Grease L641 87099184130

Worcester Bosch

Worcester Bosch Unisilkon Grease L641 87099184130

Worcester Bosch L641 Unisilkon grease, part 87099184130, for lubricating seals and moving components across 105 Worcester British Gas boiler models.

At a glance

  • Part type: Gaskets, O-rings, seals and washers
  • Also known as 1031001
  • This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Manufacturer part no.
87099184130
Showing prices

£34.39

£28.66 ex. VAT · VAT at 20%

Available to order · 3 working days
Available to order · 3 working days
Not certain it's the right part? The technical team verifies fitment before dispatch — no charge, and it stops a second trip.Call the technical teamSend a technical question

Same-day dispatch

Ordered by 4pm Mon–Fri, 10:30am Sat.

30-day returns

Unused, in original packaging.

What it is

Unisilkon grease is a silicone-based lubricant supplied by Worcester Bosch for use on seals, O-rings and moving components during boiler service and repair. It is listed under the manufacturer's gasket, O-ring, seal and washer range, and is intended to keep rubber and plastic parts supple and free-moving when components are reassembled. The L641 reference identifies this particular grease specification within the Worcester Bosch spares catalogue.

Signs this part needs replacing

  • Seals or O-rings feel dry, stiff or tacky when a component is stripped down for service
  • Moving parts bind or squeal during operation instead of travelling smoothly
  • Rubber seals show cracking, flattening or hardening around the seating face
  • Components are difficult to refit because the existing lubricant film has dried out
  • Water or gas-side joints weep after reassembly where a dry seal has not seated correctly

Before you order

  • Check the appliance GC number or serial plate against the compatibility list to confirm the correct grease specification for your model
  • Confirm whether the previous number DD97939914 or alternative number 1031001 appears on your existing documentation
  • Check whether a replacement gasket, O-ring or seal kit is also needed for the job in hand
  • This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.

Not sure which part?

Search by part number, product name or brand — our technical team confirms fitment before anything is dispatched.