Fresh from a service, this Mack shut down on the highway with no oil pressure. The sump plug had fallen out — completely stripped. We fixed it properly. Here’s what happened.
The owner of this bonneted Mack thought everything was sorted. The truck had just come back from a routine service — nothing fancy, just the basics to keep it ready for the next haul.
But not long into its first drive post-service, things went very wrong.
The truck was cruising along a regional highway when the oil pressure warning light lit up — followed by a complete engine shutdown. The driver did the right thing: pulled over immediately and made the call.
It was towed into Webbie’s Mechanical, and the moment it arrived, we went straight to the likely suspect — the sump.
What we found?
The sump plug was missing.
Gone. Not loose — completely gone.
We checked the sump, the threads were completely stripped, meaning it was most likely overtightened. Bit by bit, it worked itself out… until all the oil drained out of the engine mid-drive. The truck was lucky to have shut itself down before more damage was done.
We got to work:
- Re-tapped the sump thread to the correct size
- Fitted a properly torqued new plug
- Refilled with clean oil
- Carried out a pressure test to confirm everything was sealing and holding
The Lesson?
Not all servicing is created equal.
At Webbie’s, we don’t just change the oil — we torque the plug properly, check the threads, and make sure every bolt is doing its job.
Because shortcuts don’t save time when your truck ends up on a tow truck.
