Giving a Tired 5.3L Vortec V-8 a Refresh Photo Gallery
Lube & Tune
Edward A. Sanchez –
Jan 25, 2017
Photo 1/16 | 5.3L Vortec V8 Refresh Lead
Photo 2/16 | 5.3L Vortec V8 Refresh 002 | One of the first things to do on a gasoline-powered used vehicle with an unknown service history is to check and replace the spark plugs. Good thing we did. Based on the 0.06-inch electrode gap and crusty electrode, it appears the plugs in our 165,000-mile Avalanche were original.
Photo 3/16 | 5.3L Vortec V8 Refresh 003 | The new Denso Iridium plugs came out of the box with the specified 0.04-inch gap. Nonetheless, it’s never a bad idea to check the gap on new plugs anyway.
Photo 4/16 | 5.3L Vortec V8 Refresh 004 | We also replaced the spark plug wires. Over time, old wires can arc and cause misfires. Be sure to retain the metal sleeve off the old plug wire.
Photo 5/16 | 5.3L Vortec V8 Refresh 005 | We applied some antiseize compound to the thread of the plugs to facilitate future service. Be careful not to get the compound on the electrodes. Hand-thread the plugs into the head to get them started. Check the recommended plug torque specifications of your vehicle’s engine.
Photo 6/16 | 5.3L Vortec V8 Refresh 006 | Now comes the fun part. We were getting scan codes indicating a faulty knock sensor. Removing the knock sensors on Gen-III GM small-blocks requires removing the intake manifold to access them. The first step is to depressurize the fuel line and disconnect it from the fuel rail and manifold, which on our engine can be removed as a single assembly.
Photo 7/16 | 5.3L Vortec V8 Refresh 007 | As we expected, it was a literal rodent’s nest underneath the manifold, with ample telltale amounts of guano to indicate it was inhabited at some point.
Photo 8/16 | 5.3L Vortec V8 Refresh 008 | We carefully vacuumed up the guano and debris from underneath the manifold, making sure none dropped into the intake ports. If you’re extra-cautious, you can cover the ports with masking tape.
Photo 9/16 | 5.3L Vortec V8 Refresh 009 | Once we got the large dirt and debris out of the way, we wiped down the valley cover and area around the intake ports with brake cleaner to clean off any residual grime and grease. Depending on the age and condition of the engine, this may take a while.
Photo 10/16 | 5.3L Vortec V8 Refresh 010 | When we removed the old knock sensor harness and sensors, it was easy to see why we were getting the fault codes. The rear sensor was so badly deteriorated, it was barely recognizable.
Photo 11/16 | 5.3L Vortec V8 Refresh 011 | After thoroughly cleaning the valley cover and around the intake ports, we installed a new harness and the new knock sensors. Before reinstalling the manifold, we added a U-shaped bead of RTV silicone around each of the sensor covers to prevent unwanted moisture intrusion. While we had the manifold off, we also replaced the oil pressure sending unit, since we had easy access to it.
Photo 12/16 | 5.3L Vortec V8 Refresh 012 | It’s recommended that the intake manifold gaskets be replaced if you take the manifold assembly off. The ones we got were one-piece stamped metal units that conveniently aligned on the intake ports, making reassembly easy.
Photo 13/16 | 5.3L Vortec V8 Refresh 013 | We also replaced the foam blocks at the front and rear of the manifold that act as debris and moisture barriers to the valley cover. Some technicians recommend leaving the rear block out to let moisture roll off the back of the valley cover and not accumulate in the rear knock sensor cavity.
Photo 14/16 | 5.3L Vortec V8 Refresh 014 | It’s important to reconnect all harnesses, connectors, and fuel lines when you reinstall the manifold. Late-model engines have myriad sensitive electronics that require the proper signals and feedback to run correctly.
Photo 15/16 | 5.3L Vortec V8 Refresh 015 | Finally, we performed an oil change on the engine with Amsoil 5w-30 synthetic motor oil and filter. Most of the LS-type truck engines take about 6 quarts. If you have an auxiliary oil cooler on your truck, you may need to add a little more.
Photo 16/16 | 5.3L Vortec V8 Refresh 016 | Resetting the oil life monitor is a relatively easy process. We were able to do it through the Driver Information Center (DIC) menu. Check your owner’s manual for the precise sequence.