3 common problems with the Ford Boss 6.2 liter engine

Ford’s reputation as an engine builder was enhanced by successes such as the 427 cubic inch V8 that made history at the 24 Hours of Le Mans and the 5.0 liter V8 Coyote, which is one of the best 8 cylinder engines ever produced. Not all Ford engines were an unqualified success, however. The first Mustang came standard with a lean inline-six, and the second generation arrived in 1974, just as the oil crisis and new emissions regulations were turning American buyers away from big engines. Automakers have since developed ways to make larger engines more efficient, and Ford planned to use the 6.2-liter Boss V8 in the Mustang when it was still codenamed “Hurricane.”

The engine inherited only a few elements from its modular predecessors, and Ford used it primarily in the Raptor and Super Duty trucks starting in 2010. In its decade or so in production, the 6.2-liter Boss V8 developed a reputation among owners for problems with spark plugs, valve springs, oil consumption, and leaks. The first two problems could cause rough operation (especially at idle) and lead to bigger problems, but Ford’s Boss V8 is still regarded as a reliable engine with a long life.

Read more: Every Ford EcoBoost engine ranked from worst to best

The Boss 6.2 used 16 sometimes annoying spark plugs

Gasoline engines typically use one spark plug per cylinder, but larger ones like the Boss V8 are designed with two to maximize power and fuel efficiency. These gains are only available to owners who change plugs regularly, but the additional plugs and coil packs required make this job twice as expensive and time-consuming as it is on other V8s. Doubling the plugs also means doubling the potential points of failure, and the plugs on the sides of the engine and near the firewall are particularly difficult to change. In a thread on F150forum.com, a user named Augster mentioned the need to remove the front wheels and fender liners to gain access to the lower plugs and estimated that the job should take “3 to 4 hours for the average tree shade mechanic.”

That’s if everything goes according to plan; some owners report that their plugs broke during disassembly or the threads got stuck in the cylinder head. This could turn a routine task into a major repair involving head removal and perhaps additional work to clean the pieces of porcelain from the cylinders.

Broken valve springs are common on Boss 6.2L V8 models

The 6.2-liter Ford Boss V8 produced close to 400 horsepower, which puts a lot of stress on the internals. Many owners report that their valve springs were not up to scratch and broke, causing their engines to run rough. They’re easy to replace and might make the engine run a little weird just if they’re broken, but if the valve stem falls into the cylinder, it could wreak havoc on the pistons and cylinder walls. There are several threads on the Ford Truck Enthusiast Forum page about broken valve springs on Boss engines, though most owners have dismissed it as a fixable problem that has had no lasting consequences for them.

Ron94150 commented on a thread with: “While broken valve springs and clogged cats are the most common problems with the 6.2, … it’s still not common. Usually the valve is either pushed against the piston or doesn’t cause any damage. I wouldn’t be [too] worried about it.” River Wild agreed, writing, “I wouldn’t worry about it. Mine is fine and I’ve been beating it pretty hard for the last 2000 miles since I fixed it. I lost a spring at just over 11K. I think I’m good for the life of the truck now.”

The 6.2 liter Boss V8 is prone to various oil leaks

Another common subject of complaints by 6.2 liter Ford Boss V8 owners is internal and external oil leaks leading to excessive oil consumption and potential emissions test failures. The fact that many owners report this problem is partly due to the durability of the engine. All engines will develop leaks over time as gaskets dry out and heat warps metal components, and the typical long service life of this engine means it is more likely to reach an age where oil leaks through the rear main seal or valve covers or slides past the piston rings.

An owner discovered that his internal oil leak was coming from a leak in the passenger side valve cover baffle, and Ford acknowledged the issue with technical service bulletin 15-0161 in October 2015. The advisory noted that “Some 2015-2016 F-Super Duty 250/350 and 2015-2016 vehicles equipped with the 20/3/1 engine and 6.23/1 built on 2015-2016 until 08.09.2015 may have excessive oil consumption due to an internal leak in the right side valve cover” and recommended its replacement. Some owners have reported problems with the positive crankcase ventilation (PCV) valves that help burn excess oil, and mentions of leaking rear main seals are common on Ford truck forums. Leaks from the rear main gasket can be difficult to distinguish from oil pan gasket leaks or higher on the engine, as well as labor-intensive repairs.

Our methodology

To identify the most common issues with the Ford Boss 6.2L V8, we first searched our own archives for previous reports on the engine. After supplementing this with a few articles from trusted sources, we scoured forum sites for owner testimonials that support our initial findings. While these three problems are common to many owners, we also found plenty of testimonials from owners who have put 200,000 miles or more on their trucks without significant problems.

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Read the original article on SlashGear.