Hydrotek 4000 Valve Cover Leaks: O-Ring Replacement Guide

Stop Leaks by Replacing Worn O-Rings

Leaks around the bonnet and cam cover screws on a Hydrotek 4000 usually mean the O-rings have micro-tears or compression set—even if they look okay. For the low cost of O-rings, replacement is the first step.

Procedure

1. Shut off water and relieve pressure.
2. Remove bonnet and cam cover.
3. Replace all O-rings with matching hardware-store sizes.
4. Inspect sealing surfaces for pitting or roughness; if damaged, the bonnet may need replacement.
5. Reassemble with silicone lube on O-rings.

If leaks persist after O-ring swap, the sealing surfaces are likely eroded and the bonnet must be replaced.