Why We Don’t Use Customer-Supplied Parts in our Diesel Truck Repairs

worried man looking under car hood

At NW Diesel Service, we have a very strict policy – we do not install customer-supplied parts. We’re sorry if your brother/father/friend/spouse works at the parts store and can get you a really good deal, but this policy has everyone’s best interest in mind.

A quick Google search reveals hundreds of examples from diesel repair shops of repair jobs gone wrong because of customer-supplied parts. Here are a couple of examples of why we have this policy in place:

Customer-supplied parts often mean the customer diagnosed the issue.

“Hey, I need a #3 injector installed, I already bought the injector, how much to put it in.” Sorry, no. First, how did you determine it’s #3 injector? More importantly, why did the injector fail? Properly diagnosing a problem goes way beyond a scan tool telling us which part has failed.

We also look at the likely reasons surrounding the failure, to ensure that (a) it won’t fail again, and (b) there isn’t a larger issue occurring and the injector failure is actually the symptom, not the root cause. Last comment on this scenario – what happens if the injector you supplied fails and ruins the engine. Folks, this happens!  I’ll tell you what happens – nobody wins.  You’re upset and want to (incorrectly) blame us. Whoever you purchased the injector from tells you either (best case) that they will replace the injector, or (worse case), “sorry dude, we can’t help you, we have no idea what happened.”  Meanwhile, nobody is buying you a new engine. If we diagnosed the failure, sold and supplied the injector, and it failed, causing engine damage – guess what?  We’re fixing your engine!

diesel fuel injector close up

The Customer provided the wrong parts.

This story isn’t from the internet – this one is personal.  Years ago, before our strict ‘no customer supplied parts’ policy, we used to allow this on occasion.  This particular truck was diagnosed by us as needing an ECM (the main vehicle control computer).  At that time, we were working on trucks at a different shop, and it had an uphill ramp into the bay doors, meaning a vehicle which did not run needed to be pushed or towed up the hill.  The customer promptly supplied an ECM, which was wrong.  He ran out again to swap it for another – wrong again.  By now we had a line up of trucks needing repairs, and this vehicle was tying up valuable space on our only hoist!  So, we pushed it out.

this is why we don't use customer-supplied parts

Multi-pin wire connector

The next day the customer finally provided the correct ECM, and instead of appreciating the difficulty he’d caused us, was rather insistent that we stop what we were doing to install and program his ECM so he could get back to work a day late. Then came the argument discussion related to the additional time spent dealing with these issues and pushing his truck around – at the end of the day, nobody was happy.

So, here’s the thing: this could have just as easily happened if we were supplying the part.  We could have received 2 wrong ones from our supplier before getting the right one.  He may have still been delayed the extra day.  These things do happen – we do our best – but certain issues are beyond our control.  However, if this were an ordinary job, all these delays would have been our problem.  We would never have attempted to charge the customer for additional time, in fact, given the delay, we would have loaned him a vehicle.

So, that’s it. No customer supplied parts. Truly, it’s in everyone’s best interest.

Or, as others in the industry have famously told their customers: go to Safeway, buy 2 eggs, then take them to McDonald’s and ask them to cook them for you.