Ford 6.8 V10 Engine Problems – Is This Behemoth Reliable?

Ford 6.8 V10 Engine Problems – Is This Behemoth Reliable?

September 17, 2023 0 By CarGuy

Are you interested in buying a Ford with the 6.8 V10 Triton engine and want to learn more about the Ford 6.8 V10 engine problems? If that’s correct, you are in the right place, because in this article, there will be a lot to cover on this specific engine.

Having good research done before you jump on the market and buy a vehicle is always a good idea, you just don’t know what you are going to get. This is why research is the key in order to avoid ending up with a problematic model. And when it comes to cars and trucks, there can be a lot of what could go wrong. That’s why we are here to help you out.

So, what are we going to cover today? First, we are going to learn more about the specs and applications of the 6.8 V10, then we are going to cover all the Ford 6.8 V10 engine problems and we will also comment on the reliability of this engine. So, let’s get started!

Ford 6.8 V10 Engine Specs

The 6.8 engine is a Ford engine that was developed in the late 90s for Ford’s heavy-duty vehicles like vans, SUVs, and Super Duty pickup trucks.

This V10 engine is based on the Modular design that was introduced by Ford during this era, and the 6.8, along with the 4.6L and 5.4L was one of the biggest representatives of this engine design.

Nevertheless, the 6.8 V10 is a mammoth of an engine, but very modern for today’s standards. This engine instead of relying on the pushrod design, is using a different approach, and that is the overhead camshaft layout.

So, on top of each cylinder head, there is a camshaft that drives the engine. There are two variations of the 6.8, a 2-valve and a 3-valve that makes a bit more power. The 3-valve version was released in 2005.

Here are some of the most important specs of this 6.8 engine.

  • Configuration: V-engine
  • Number of cylinders: 10
  • Displacement: 6.8L
  • Bore: 3.552 in (90.2 mm)
  • Stroke: 4,165 in (105.8 mm)
  • Block Material: Cast Iron
  • Head Material: Aluminum
  • Head Design: SOHC, 2-valve or 3-valve
  • Compression Ratio: 9.2:1
  • Horsepower: 305 – 362 hp
  • Torque: 420 – 460 lb-ft

Ford 6.8 V10 Engine Applications

Now let’s list the applications of this 6.8 V10 engine.

6.8 2-valve

  • 1997 – 2004 Ford E250 – E450
  • 1999 – 2004 Ford F250 – F550
  • 2000 – 2005 Ford Excursion
  • 2005 – 2019 Ford E350 & E450

6.8 3-valve

  • 2005 – 2010 Super Duty
  • 2005 – 2019 F450 – F550 Chassis Cab Truck
  • 2012 – 2019 Ford F650/F750 Super Duty
  • 2011 – 2021 Blue Bird Vision
  • 2005 – 2019 F53 and F59 Stripped Chassis
  • 2004 – 2013 New Flyer Low Floor Bus Application

Ford 6.8 V10 Engine Problems

Now let’s list the common problems with the Ford 6.8 V10 engine.

  • Spark Plug & Coil Failure
  • Spark Plug Blowout
  • Intake Manifold Leaks
  • Exhaust Manifold Leaks
  • PCV Valve Hose Cracks
  • Poor MPG

We listed the most common problems with the 6.8 V10 engine, now let’s further elaborate on each one of these problems.

Why do we feel the need to do so? Well, you need to become an expert on these issues and you need proper input to do so. That’s why we feel the need to further elaborate on these problems and learn more about the circumstances when and how they occur and how serious these problems are. So, let’s dive into the issues and explain them in detail.

1. Spark Plug & Coil Failure

One of the most frequent problems with the 6.8 V10 engine is problems with spark plugs and ignition coils. Basically, these are ignition problems.

The ignition components tend to fail quite often since these are heavy-duty engines and tend to run pretty hard.

Also, these are the first engines that use coil over plug layout and these first series did have more problems compared to current versions of the same engine.

What is worth noting is that whenever you have problems with the ignition components you will experience a check engine light, engine misfires, rough idle, poor engine work, and poor fuel economy.

Troubleshooting the problem can only be done with an OBD2 scanner. With this tool, you will be able to get the trouble codes and see which coil and spark plugs are misfiring.

Then, based on this you can swap out the coils between the cylinders to troubleshoot the bad coil if the problem is in the coil itself. Then replace the faulty coil with a new one.

Now let’s continue with the next Ford 6.8 V10 engine problems.

2. Spark Plug Blowout

The next most common problem with the 6.8 engine, as well as with the 5.4L and 4.6L from this Modular family is the spark plug blowout. What is a spark plug blowout?

A spark plug blowout is a situation where spark plugs end up welded with the cylinder head. In this case, the treads for the plugs will simply deteriorate.

Whenever this happens, the spark plug could simply be blown out of the cylinder and you will be left without compression on one of the cylinders.

Luckily, since this is a common problem there are solutions. There are kits that are sold. These kits include new treads and also a tool to install them. This process can reportedly be done without removing the cylinder head.

In the video, you can see how this process is performed on an engine of this type.

3. Intake Manifold Leaks

Intake manifolds are also a common problem on these Modular engines, including the 6.8 V10 engine.

For those who don’t know, the intake manifold is the component that is installed on top of the valley of the V-engine.

This intake manifold feeds the intake ports with air that is needed for combustion. This manifold is prone to problems in these engines.

The gaskets can fail, as well as there can be some cracks that will develop and cause air leaks. These air leaks will allow unmetered air to enter the engine.

This will result in bad air-to-fuel mixture and the engine will run poorly. The engine could run rich or lean and start to stall, lose power, and so on.

And finding these leaks can also be a challenge. They can only be properly tracked by using a smoke machine.

Now let’s move on to the next Ford 6.8 V10 engine problems.

4. Exhaust Manifold Leaks

The exhaust manifolds can also lean on these 6.8 engines. So, what are these components and why do they leak?

The exhaust manifolds are the components that redirect exhaust gasses from the exhaust ports into the exhaust system.

These are cast iron components that are very durable but the bolts that are holding them not so much.

The manifolds go through a ton of cooling and heating cycles in these trucks and they can end up breaking.

Also, these bolts are very much exposed to the elements and salt can eat them quite easily.

Whenever these leaks appear, there can be hissing sounds, ticking sounds, and the smell of exhaust fumes in the cabin and in the engine bay, as well as check engine light and poor engine performance.

The solution to this problem is to install new studs and new bolts. This would solve the problem permanently.

5. PCV Valve Hose Cracks

A problem with the PCV system was also reported on this 6.8 V10 engine. But what is a PCV system?

The PCV system is the positive crankcase ventilation system. What this system does is redirect the vapors created in the crankcase into the intake so they burn off.

This is a crucial system because this system extends the life of the engine. If it ends up closed it can cause some seals and gaskets to fail.

Also, if the hose ends up cracked, there can be vacuum leaks. These vacuum leaks can cause your engine to perform poorly.

So, if there are cracks around the PCV valve hose, it is crucial that you replace this component with a new one in order to avoid further problems.

Now let’s move on to the next Ford 6.8 V10 engine problems.

6. Poor MPG

And last but not least is the poor fuel economy. Many people think that these engines are not that bad on fuel. But they are.

The MPGs for this engine are really poor. You will only get 8 or 9 MPG in the city and a maximum of 14 MPG while cruising on the highway.

So, that’s why sometimes it is a much better idea to get a smaller displacement engine or a turbo diesel instead of this V10.

Ford 6.8 V10 Engine Reliability

The reliability of the 6.8 V10 is very strong, this engine is built like a tank and it is a very reliable truck engine.

So, if you think that you need something reliable and don’t care about fuel economy, this engine will be the perfect candidate.


In this article, we covered quite a lot when it comes to the Ford 6.8 V10 engine. First, we learned more about the specs and the applications of this engine.

In the second part, we learned more about the problems of the 6.8 V10 engine and we also gave a comment on its reliability. Overall, this is a very good engine that has an excellent reliability score.


What Are The Common Ford 6.8 V10 Engine Problems?

Common problems with this engine include ignition problems, spark plug blowout, and PCV hose tends to crack often. There can also be leaks from the intake manifold and exhaust manifold, the exhaust manifold bolts can break and cause leaks to develop.

Is The Ford 6.8 V10 Engine Reliable?

Yes, these are pretty reliable engines that will run forever if you maintain them well. The only drawback is their fuel consumption which can be really heavy.