Master Tech:
Duramax Diesels

Happy beginning of the fall season to all. I hope the air conditioning service I discussed last month has paid off for the shops that offer it.

This month I want to talk about Chevrolet Duramax diesel pickups. There is money to be made from servicing these Duramax engines. They usually hold 10 quarts of oil and require an up-chargeable oil filter.

Let’s concentrate on servicing these vehicles starting with changing the oil filter. The Duramax requires a PZ59, which can usually be half primed with oil. Every time your shop removes the oil filter, it’s very important to check the oil filter adapter fitting (the threaded part where the filter spins on) because these adapters will back out, and if you don’t retighten them into the housing, the oil filter could fall off. And should the oil filter fall off, your shop will be replacing an engine.

Next, let’s talk about the diesel fuel filter. On the old Duramax engines (up to 2007), the filter is easily replaced. Be sure to transfer the water sensor, and be sure the ring fits into the filter housing correctly.

However, if you are servicing a 2007-2010 Duramax, the access we once had is gone. We’ve found it’s best to turn the steering wheel all the way to the left and pull the inner passenger-side fender so you can unplug the water sensor wire and remove the filter from the bottom. Also, be sure it’s tight and not leaking any air or fluid.

To prime the Duramax fuel filter, remove the black plastic screw cap and push the silver ball repeatedly until fuel comes out the hole. Then, reinstall the plastic cap and pump the ball more until it is hard to push and, eventually, until you are no longer able to push it. Then, fire the engine to check for air and fuel leaks. Also, it helps to hold the filter with a band wrench to remove the water sensor from the bottom.

JEREMY O’HORA is owner of three shops in central Texas. He is an ASE L1 Master-certified technician with more than 12 years experience in dealership, independent and fast lube settings. He is also a Silver-level trained Chrysler and a GM Master Certified technician, with more than 3,000 hours of secondary training. He can be reached at 830.792.4686 or: jeremy_ohora@yahoo.com