Oil consumption problems have plagued many models of the GMC, including the GMC Terrain.
Several lawsuits have followed because there has been no recall for vehicles with excessive oil consumption.
In response, GMC has released several TSBs to help car owners and technicians resolve the excessive oil consumption in their vehicles.
They have also offered special coverage to vehicles that meet specific conditions relating to oil consumption.
We shall examine the causes of excessive oil consumption and some of the fixes GMC recommends to fix your Terrain.
Why is your GMC Terrain consuming excessive oil?
The primary cause of excessive oil consumption in your GMC Terrain and other GMC models is a defective piston design in the 2.4L engines.
To our newbies, the piston is a moving part of the combustion chamber responsible for converting chemical combustion energy into mechanical energy used to move the car.
Furthermore, the piston is designed with compression and oil rings that keep engine oil. The engine should include a thin film between the piston and cylinder wall.
However, many complaints state that the low-tension oil rings have failed to prevent oil from entering the combustion chamber, causing manifold issues and leakage.
Now, because oil shouldn’t escape into the combustion chamber, some of the oil is burnt off, thereby reducing the engine’s oil efficiency.
The escaped oil also damages the spark plugs causing the car not to start properly.
Unburned oil in the chamber hardens and forms carbon build-up within the engine. This event causes further inefficiencies in fuel and oil consumption.
Compounding the problem is the oil spray jet responsible for spraying oil to prevent the piston from wearing other engine parts.
It has been reported that the oil spray jet overloads the piston with excessive oil.
Symptoms your GMC Terrain consumes excessive oil
If you suspect your GMC Terrain consumes excessive oil, some other symptoms may help you diagnose your vehicle.
1. Engine shutdown/ stall
While driving, you may notice your car’s engine stalling or shutting down more than once during a trip. Inefficiencies in the engine design cause this. It and the oil warning light may hint that you have a defective engine causing excessive oil consumption.
2. Oil warning light
You may also experience your oil warning light blinking along with other symptoms. It lets you know that the car has little or no oil due to mechanical issues or leakage.
3. Faulty spark plug
If your spark plug is always getting worse, along with other signs, it may be that your engine is consuming a lot of oil. Due to defective design, oil gets to the spark plug, damaging it.
4. Unexpected power loss
It is expected as the engine cannot generate enough power to convert into mechanical energy. You may also experience your vehicle shaking or jerking.
5. Engine misfire
Oil can get into one of the engine cylinders causing it to misfire frequently.
How does the excessive oil affect you?
Engine oil plays an important role in your car engine. It prevents the engine parts from rubbing against each other, preventing costly damages.
It also functions as a coolant cooling the car’s engine from overheating. The lack of oil can therefore cause overheating and lead to dangerous fires.
Excessive oil in the GMC Terrain should be taken seriously, as it threatens safety.
How to fix excessive oil consumption in your GMC Terrain?
Before moving into the fix, GMC has offered warranty covers to GMC Terrain that are no more than seven years, six months, or 120,000 miles, whichever is greater.
They require authorized dealers to replace the four pistons in the 2.4L engine and repair them at no charge. Ensure you check if this warranty applies to you.
Troubleshooting further may void the coverage. Let’s proceed!
If you suspect your engine is defective and consuming excessive oil, perform the following test.
- Confirm the ECM has the latest TIS2Web Calibration to adjust the engine life to 7,500 miles.
- Oil consumption test: The oil consumption test helps determine the condition of the rings and pistons.
- If the oil test indicates a consumption rate of less than a quarts/2000 miles, only note the rate and date the ECM was reprogrammed.
- If the oil consumption rate reveals a rate of greater than 1 quarts/ 2000 miles, not the rate and date the ECM was reprogrammed
- Proceed to replace the pistons and rings in the engine.
Replacing the pistons and rings in the engine is complicated and requires some technical expertise.
- Remove the engine from the car
- Remove the pistons from the 2.4L engine
- Remove pistons from connecting rod
- Install new pistons to the connecting rod
- Reassemble the engine.
Frequently Asked Questions (FAQ)
Is there an additive to stop oil burning?
If the cause of your oil burn is mainly a damaged piston, no amount of additive can prevent the oil burn or its oil consumption. We recommend replacing your engine’s pistons to stop excessive oil consumption.
Will thicker oil stop oil consumption?
Using the right oil viscosity will go a long way in improving your oil consumption. However, ensure that the cause of your vehicle’s excessive oil consumption is not a bad piston.
For all of our readers with affected GMC terrain, we recommend you check if your GMC terrain is still covered under the special coverage warranty.
This coverage can help you save thousands of dollars. We also encourage reading a lot of their TSBs.
Unfortunately, the only solution for your GMC Terrain is to replace its piston. It can be quite expensive.