Released in 1970, it was the final evolution of Holden’s original “full-size” pre-HQ era, sitting right at the crossroads between the old-school Kingswood formula and the more modern HQ that would follow shortly after. The HG refined what came before it — slightly sharper styling, improved comfort, and the same big, simple mechanical layout Australians trusted.
Survivors are becoming harder to find, especially in clean, unmodified condition. Many have already been restored, modified, or slowly returned to the earth after decades of neglect.
Here are the most common HG Holden problems owners and buyers should know about.
1. Rust Problems
Rust is, without question, the biggest issue affecting HG Holdens today.
These cars were built before modern corrosion protection methods became standard, and many spent their lives outdoors or working in harsh Australian conditions. By now, rust is almost guaranteed somewhere on most surviving examples.
Common rust areas include:
- lower doors
- rear quarter panels
- floor pans
- boot floors
- chassis rails
- windscreen surrounds
- sill panels and jacking points
Utes and wagons are often the worst offenders due to heavier use and exposure.
Common symptoms
- Bubbling paint around arches or sills
- Soft or weakened floor sections
- Water leaks into cabin or boot
- Rust holes hidden under trim or carpets
- Thick filler covering previous repairs
A rust-free HG shell is now one of the most valuable starting points for any restoration because proper repairs are time-consuming and expensive.
Related guide
- HK, HT, HG Holden Rust Problems
- How to Inspect an Early Holden Before Buying
- Best Rust Protection Products for Classic Holdens
2. Holden Six-Cylinder Engine Wear
The HG was powered almost exclusively by Holden’s well-known straight-six engines, including the trusty 186 and 202.
These engines are famous for their simplicity and durability, but after more than five decades, wear is unavoidable.
Common issues include:
- oil leaks from aged gaskets and seals
- worn timing chains
- carburettor tuning problems
- overheating under load
- general loss of compression in tired engines
Many HG engines have also been rebuilt, modified or swapped over the years, so condition can vary significantly from vehicle to vehicle.
Common symptoms
- Rough idle or hesitation
- Hard starting, especially cold
- Excessive oil consumption
- Reduced power output
- Engine noise from worn internals
The upside is that these engines are still straightforward to work on and parts remain widely available.
Related guide
- Holden Red Engine Problems
- Holden 202 Engine Issues Explained
- Best Oils for Classic Holden Engines
3. Cooling System Problems
Cooling system issues are one of the most common causes of trouble in ageing HG Holdens.
Radiators clog internally, hoses harden and crack, thermostats fail, and water pumps eventually wear out after decades of service. Once cooling performance drops, overheating becomes a serious risk.
Many surviving HGs are still running original or very old cooling components.
Common symptoms
- Temperature gauge rising in traffic
- Coolant leaks under vehicle
- Steam from engine bay
- Sweet smell of coolant
- Poor heater performance
Overheating an old Holden engine can quickly turn a small issue into a major rebuild.
Related guide
- Red 6 Cooling System Problems
- Early Holden Radiator Upgrade Guide
- Best Coolants for Classic Holden Engines
4. Transmission Wear (Trimatic)
The HG commonly used the Trimatic automatic transmission in many models.
While simple and reliable in its day, decades of use, heat and neglect inevitably lead to wear.
Many HG Holdens have lived hard lives:
- towing trailers
- long-distance cruising
- city driving in traffic
- or running without proper servicing
As a result, transmission issues are now very common.
Common symptoms
- Slipping between gears
- Delayed engagement
- Harsh or inconsistent shifting
- Transmission fluid leaks
- Shuddering under load
Proper servicing can still improve performance if wear isn’t too advanced.
Related guide
- HK, HT, HG Holden Transmission Problems
- Trimatic Common Issues Explained
- Best Transmission Fluids for Classic Holdens
5. Suspension & Steering Wear
The HG still delivers that classic big Holden ride — soft, comfortable and built for Australian roads — but worn suspension can make it feel very different today.
After more than 50 years, most HGs now have worn:
- shock absorbers
- control arm bushes
- steering linkages
- sway bar components
Cars used for heavy work or towing are usually in worse condition.
Common symptoms
- Loose or wandering steering
- Clunking noises over bumps
- Uneven tyre wear
- Excessive body roll
- Steering vibration
A suspension refresh can dramatically improve drivability and safety.
Related guide
- HK, HT, HG Holden Suspension Problems
- Best Suspension Upgrades for HK, HT, HG Holden
- HK, HT, HG Steering System Repair Guide
6. Electrical Problems
Electrical systems in early Holdens were simple, but time introduces complexity of its own.
In the HG, wiring looms, switches and connectors are now well past their expected lifespan. Add decades of aftermarket wiring, and electrical gremlins become almost unavoidable.
Common issues include:
- charging system faults
- faulty gauges or dash lights
- intermittent starting issues
- blown fuses
- poor earth connections
Common symptoms
- Flickering lights
- Flat batteries after sitting
- Gauges reading incorrectly
- Random electrical faults
- Starting inconsistencies
In many cases, cleaning earth points solves more issues than replacing components.
Related guide
- HK, HT, HG Holden Electrical Problems
- Early Holden Starting Issues Guide
- Best Battery Upgrades for Classic Holdens
7. Oil Leaks
Oil leaks are practically expected on classic Holden engines by this stage.
In the HG, ageing seals and gaskets are the main cause, with leaks gradually developing over decades of use and heat cycles.
Common leak areas include:
- rocker cover gaskets
- sump gaskets
- rear main seals
- timing cover seals
Common symptoms
- Oil spots under vehicle
- Burning oil smell after driving
- Dirty engine bay and underbody
- Smoke near exhaust components
Small leaks are common, but larger leaks should always be addressed before they worsen.
Related guide
- Holden Six-Cylinder Oil Leak Problems Explained
- Best Engine Oils for Classic Holden Engines
8. Interior Wear & Ageing Trim
HG interiors were designed for durability, not longevity beyond half a century.
After decades of Australian sun and use, most interiors show significant wear unless restored.
Common issues include:
- cracked dashboards
- sagging roof lining
- faded or brittle plastics
- worn seat upholstery
- loose interior trim
Utes and wagons are typically the most heavily worn.
Common symptoms
- Sun-damaged dash surfaces
- Interior rattles and loose panels
- Sagging headliner
- Torn or faded seats
- General cabin ageing
Good original interior parts are becoming increasingly rare and valuable.
Related guide
- HK, HT, HG Holden Buyers Guide
- Best Interior Products for Classic Holdens
Is the HG Holden Reliable?
For a vehicle built in 1970, the HG Holden is still remarkably durable
The HG Holden represents the final chapter of Holden’s pre-HQ era — the last of the traditional full-size Australian family cars before a new design philosophy took over.
The key is starting with the best example you can find and staying ahead of maintenance before small issues become expensive restorations.
