Bulletproof is a hallmark of the GM 3.6 making it one of the most reliable American-made engines ever made. However, its Achilles heel is the need to change its engine oil.
Here are some problems to be aware of when buying a vehicle with this engine.
Excessive oil consumption
It’s no secret that a GMC 3.6 engine can use up to 1 quart of oil per 2,000 miles. GM claims that this is normal consumption, but oil change intervals can cause problems.
The problem is that the engine will run out of oil at 1 quart per 2000 miles before it lights up with the change engine oil light. Although the low engine oil light might still be visible before this, it’s very common for drivers not to have enough oil between oil changes.
Cam phasers are the first to go without oil when oil is low in these GMC engines. The timing chain is the second component that can be stripped of oil.
GM 3.6 Water Pump Failure
Coolant is circulated throughout the engine by a water pump. The water pump is responsible for maintaining engine temperatures within the specified limits. High pressure can cause damage to the internal components of these water pumps, including the gaskets and seals.
The pump must work harder to maintain coolant flow as internal components wear down. Gasket leaks or seal leaks can cause pressure drops in the system, again making it more difficult for the water pump to work properly.
The GMC 3.6 engine’s water pump can go out at a distance of between 80,000 and 100,000 miles. There are signs that a water pump is failing, and they can be caught before your engine overheats. One cause of this is that the GM 3.6s have a “weep hole”, which is a small drain hole. Coolant can leak out of the weep hole if the water pump begins to leak internally.
To prevent overheating, we recommend that you replace the water pump as soon as coolant leaks are detected. Overheating can cause internal damage and cracking of head gaskets. If not dealt with promptly, it can lead to many other problems.
GM 3.6 Timing Chain Cover Leaks
The “front cover”, also known as the timing chain cover, protects and lubricates your timing chain. The cover attaches directly to the engine block and protects the timing chain against road dirt and debris. It also helps to prevent the timing chain from slipping off its gears. The cover’s primary purpose is to lubricate your timing chain with engine oil.
GM’s timing chain has a metal front cover that is fastened to the engine block using a gasket. The gasket is exposed to heat because it sits up high on the engine block. Excessive heat causes the gasket to wear down and oil to seep out of the cover.
Failing gaskets will not only leak oil but also let air and engine pressure leak, which could lead to performance issues. It is possible to crack a timing cover, but most problems with this engine are caused by gasket failure. It is crucial to replace the gasket immediately if it fails. Not only can it cause performance problems, but it can also lead to low oil levels that can further damage the engine internals.
Failure of the Timing Chain On The GM 3.6 Engine
Low oil levels are the main cause of timing chain problems. The timing chain is the first component to become oil-starved when oil levels drop. When timing chains don’t receive enough oil, the friction causes the metal to heat. When timing chain metal temperatures increase, the chains can stretch, causing them to jump teeth.
The timing chain tensioner can also make the problem worse. The tensioner maintains the correct tension in the chain to prevent it from becoming loose or jumping gears. The tensioner is hydraulically actuated, meaning it uses oil pressure to function. Low oil levels can cause the tensioner to lose its ability to maintain enough tension in the chain.
Timing chain guides can be worn down by lack of lubrication.
Many drivers report their GMC 3.6-liter Engine reaching 200k miles when oil levels were maintained properly. It is important to remember that once you reach this mileage, there will probably be a few maintenance items such as water pumps, timing chains, and sensors.
Low or bad engine oil can directly or indirectly cause many of the issues listed. This is all you need to be concerned about. Enjoy the journey ahead!