Our AAA regional representative recently engaged New Concept Auto Service and some other local shops in a conversation about policies regarding cross-threaded oil pan drain plugs. A cross-threaded drain plug is when the threads on the plug and pan are not aligned, causing a bad fit. It just gets worse as it is tightened.
It seems like such a minuscule part to create such a firestorm of policy, but keep in mind one tiny leaking plug can drain a whole pan of oil and create need for a multi-thousand-dollar engine repair or replacement.
There are several scenarios for assessing a damaged oil pan or drain plug threads, including the rare instance of a drain plug cross-thread. Other times the drain plug is over-tightened and has pulled or damaged the threads on the plug and requires a new plug. In this instance, if the pan threads are only slightly damaged they may only need to be chased or rethreaded. Sometimes the pan has to be replaced or over-drilled if possible. And sometimes the head of the drain plug is rounded off. This happens when the wrong sized wrench or socket is used for tightening by an inexperienced person.
The key is to get our customers involved before it will cost them any money. It is nearly impossible to convince a customer they need a new oil pan during an oil change and have them believe it was not due to something we did wrong. That is certainly understandable. Customers are almost always OK with the cost of a new drain plug when we show them the old, damaged one. Most always they are simply stripped or about to strip from over-tightening. Sometimes they are just finger tight! Customers are usually grateful that they have avoided seeing the dreaded oil light appear while driving down the Overland Parkway!
At New Concept, we use written procedures for every single thing that happens in the shop. If you don’t believe that, just ask the guys next time you come in and they will probably roll their eyes and say, “Yes, Paul is a procedure guy.”
Our procedure for assessing the oil plug situation goes like this: We simply try to pop the plug loose with a long wrench. If it begins to get tight as it comes out, we know it will need at least a thread chase and a new plug. We get the customer involved at the point the plug starts to get tight, knowing we can likely just tighten it back up. We actually offer to show the customer the situation in the shop.
I’m out of time today, but check back next week for a funny customer story, and our fail-safe procedure to ensure the oil keeping your engine running stays put.