Choosing the Right Engine Oil for Your Holden or Chevrolet LS/LT Engine

"Race-spec LS engine with all the go fast bits. Engines like this need oil chosen to suit the build."

Choosing the Right Engine Oil for Your Modified LS/LT V8

Whether it's a Commodore, Monaro, Ute, Camaro, or an LS swap into something completely different, the right oil is one of the cheapest ways to protect an expensive engine. Oil that's fine for a stock daily driver isn't always right once you've added a cam, a blower, or regular track days. Here's how to choose.

Start with the basics: what does oil actually do?

Oil lubricates, cools, cleans, and protects against wear. Modifications increase heat, pressure, and load on all of these jobs. Two numbers matter most:

• Cold viscosity (the first number, e.g. the "5W" in 5W-40): how easily the oil flows on start-up. Most engine wear happens in the first few seconds after a cold start.
• Hot viscosity (the second number, e.g. the "40"): how well the oil holds a protective film at operating temperature.

Stock or lightly modified engines

Intake, exhaust, tune, mild cam, naturally aspirated, mostly street driven

Recommended: 5W-30 or 5W-40 full synthetic

Most factory LS and LT engines were designed around 5W-30, and it's still a great choice. In hot Australian summers, or on an older, higher-kilometre engine, 5W-40 gives a little extra film strength without sacrificing cold-start protection. Always check your owner's manual for the factory specification as your baseline.

Heavily modified engines

Supercharged, turbocharged, big cams, nitrous, track or drag use

Recommended: 5W-50 or 10W-60 full synthetic, or a dedicated performance/racing oil

Forced induction and hard driving mean higher oil temperatures and greater bearing loads. A thicker hot viscosity helps maintain the oil film under those conditions.

A word of caution: thicker isn't always better. Oil that's too thick flows poorly on cold starts, adds drag, and can raise oil temperatures. Match the oil to the build, not to what sounds toughest.

Things to check for your specific setup

Cam type and zinc (ZDDP). Nearly all LS/LT engines use roller camshafts, which don't need high zinc levels. If you're running a flat-tappet cam, you do need an oil with higher ZDDP.

Gen V LT engines with AFM/DFM (cylinder deactivation). These systems are sensitive to oil quality and oil level. Use an oil that meets the manufacturer's specification and keep up with your changes. If you've deleted AFM/DFM with a tune, a non-AFM cam and lifters, this concern no longer applies.

Oil temperature. If your oil regularly exceeds about 110°C, thicker oil is only part of the answer. Consider an oil cooler.

Towing and heavy use. Extra load means extra heat. Treat it like a performance application when choosing viscosity and change intervals.

How often should you change it?

Modified engines work harder, so oil breaks down faster. As a guide:

• Street-driven, lightly modified: every 5,000 to 7,500 km or 6 to 12 months
• Boosted or hard-driven: every 5,000 km or 6 months
• Track or drag use: after every few events, or sooner, depending on how hard it's driven

Always change the filter with the oil, and use a quality oil filter.

Why we use and recommend Nulon

At our workshop, we use and recommend Nulon oils for all of our engine builds and servicing. Nulon is an Australian-owned brand, and its oils are formulated with local conditions and Australian driving in mind. We trust it in the engines we build, and we're happy to put our name behind it in yours.

Using one oil across all our builds and services means we know exactly how it performs in the engines we work on, and we can give you consistent, confident advice.

Built your engine with us? We'll tell you exactly what to run

If we've built your engine, you don't need to guess. We'll tell you exactly which oil to use and when to change it, based on the components we've fitted, how the engine was built, and how you plan to drive it. That includes the correct viscosity and the right service intervals for your combination, including any special running-in requirements for a fresh build.

Quick reference guide