SUPERTECH inlet and exhaust valve stem seals Opel Z16LER Z18XER A18XER set of 16

Opel and Vauxhall engines concerned

This full set of 16 seals targets the Opel and Vauxhall 16-valve fours with 5 mm stems: the 192 hp 1.6 Turbo Z16LER, A16LER and B16LER of the Corsa D OPC and Corsa VXR, then the 140 hp 1.8 Z18XER, A18XER and B18XER of the Astra H and J GTC, Insignia A, Mokka, Zafira B and Zafira Tourer C, built from 2005 to 2019.

These blocks have 8 inlet and 8 exhaust valves, which Opel fits with seal 24405819 and SUPERTECH caps with one integral seal on both sides. The 16 pieces of this set therefore handle the whole head; each seal sits on the guide and lets only useful oil down.

SUPERTECH inlet and exhaust valve stem seals

Whether it is the turbo Z16LER of a Corsa OPC or the A18XER of a Zafira, each seal must oil the 5 mm stem and keep the rest of the oil above the guide. Repeated heat ends up hardening its lip, which then lets oil by: top-ups become needed between services, a blue plume escapes when the Z16LER fires up cold or when leaving a long idle, and carbon invades 16 valves and 4 plugs.

SUPERTECH's VSI-GM50-E, an integral Viton (FKM) part for the Z16LER family, matches the 10.06 mm guide and 5 mm stem of these engines. This set of 16 groups the Z16LER or A18XER inlet and exhaust seals under one reference: one order covers the whole head.

Stem seal technical specifications

Stem seal installation

Technical guide

The brand offered

Settled in San Jose for over 30 years, the Californian company SUPERTECH produces competition valves and supplies springs, guides and seals alongside. Ultrasound, X-rays and laser check every batch, later approved by recognised tuners on dyno and circuit.

Inlet or exhaust?

For the Z16LER, Z18XER and A18XER, SUPERTECH lists one model: its integral VSI-GM50-E in Viton (FKM) fits the 8 inlet valves and the 8 exhaust valves, with a 5 mm stem and 10.06 mm guide throughout. The VSI-GM50-E's Viton holds 204 °C (400 °F) continuously per SUPERTECH, a handy reserve where heat peaks, at the exhaust. A set of 16 fits the whole engine.

When valve stem seals must be replaced

• Frequent top-ups, blue smoke as the Z16LER starts
• 16V head being rebuilt, valves out
• All 16 guides changed
• Stiffer springs or competition valves in

Vehicle compatibility

OPEL

VAUXHALL

OEM part number (Opel stem seals): 24405819 (6 42 002)

Remember the Z16LER Z18XER A18XER uprated valves

Head open? Take a look at the engine's 16 valves too. For the Z16LER family inlet, SUPERTECH produces uprated valves: