2007 Jeep Commander 4 7l Continuous Misfire and Losing Power When Accelerating While Hot

The 3.7 PowerTech was designed and manufactured by Chrysler from 2002 until 2012. The engine was the base engine option for Dodge Ram trucks as well as a number of other Dodge and Jeep mid-size vehicles. Producing 210hp and 235 lb-ft of torque, the engine lacked in power and fuel economy which eventually lead to its replacement.

2005 brought a revision to the 3.7L PowerTech, increasing the compression ratio, redesigning the combustion chambers, and revamping the cam, piston rings, and cylinder head covers. Additionally, an electronic throttle body and exhaust gas recirculation were added in 2007.

In 1999, Chrysler launched the 4.7L V8 PowerTech, which was the standard V8 engine option for Dodge trucks and Jeeps. The 3.7L V6 PowerTech is virtually the same engine as its V8 bigger brother, minus two cylinders.

In 2011 the new Chrysler Pentastar V6 engine began replacing the 3.7 PowerTech, and eventually fully replaced it by the end of 2012. The Pentastar was more a more advanced engine offering more power and fuel efficiency compared to the 3.7.

Cars Using the 3.7L PowerTech

Despite being technically manufactured by Chrysler, the 3.7 PowerTech never made its way into a Chrysler vehicle. Throughout the article we will refer to this engine as the Dodge, Chrysler, or Jeep 3.7 PowerTech interchangeably.

The 3.7 PowerTech is also frequently referred to as the 3.7 Magnum. We also use this interchangeably throughout the post

2002-2012 Dodge Ram
2004-2011 Dodge Dakota
2004-2009 Dodge Durango
2007-2011 Dodge Nitro
2002-2013 Jeep Liberty
2002-2013 Jeep Cherokee
2005-2010 Jeep Grand Cherokee
2006-2010 Jeep Commander
2006-2010 Mitsubishi Raider

Dodge 3.7L PowerTech Common Problems

Valve Seat Failure
Stuck Lifters / Lash Adjusters
Piston Ring Landings
PCV Valve

1. 3.7 PowerTech Valve Seat Failure

Valve seats sit within the engine head and are responsible for keeping both the exhaust and intakes valves fully sealed shut when the are closed. When one of the valves is closed, the head of the valve rests against the valve seat.

When a valve seat fails it can prevent the valve from fully closing which will break the airtight seal that helps maintain cylinder compression. With that being said, the end result is a loss of compression within the cylinder. When a cylinder has low compression, when air will leak out of the cylinder as it tries to compress air, essentially making the whole cylinder ineffective. This will have serious performance implications but can also create additional engine problems if left alone for too long.

On Dodge and Jeep 3.7 PowerTech's, valve seat failure is most commonly caused by excessive engine heat. Excess engine heat can warp the metal the seat is made of and therefore cause it to pop out of its position.

3.7 Magnum Valve Seat Failure Symptoms

Loss of engine compression
Loss of power
Lack of acceleration
Poor overall performance
Cylinder misfires

When a valve seat fails on V6 Magum's it is usually only isolated to one cylinder. Fortunately, one cylinder losing compression does not cause the other cylinders to lose it too; it is isolated to the one cylinder with the failed seat.

Have only one cylinder go bad can actually make it difficult to detect the problem in the first place. Your engines power will virtually be running on 5 cylinders instead of 6 which might not be very noticeable from a performance perspective if you don't get on the throttle ever.

Misfires will likely be the most common symptom. If you have misfires and replace your spark plugs and ignition coils, your next step should be to do a compression and leak-down test on all the cylinders.

3.6 Magnum Valve Seat Failure Replacement

Since the valve seats are pressed directly into the cylinder head, your only replacement option here is to rebuild or completely replace the cylinder head. You're likely going to run into a $1,000+ repair bill whether you choose to replace or rebuild the existing head. DIY'ing the repair is likely a no-go unless you are a trained machinist.

One of the best prevention tips is to make sure your engine never overheats. Heat kills valve seats so keep an eye on engine temps and if you begin to shoot over normal temps, pull over and shut your engine off. Keep your engine fresh on coolant and flush/replace the coolant as recommended. If you have power mods on your engine you can consider adding some cooling modifications but I don't recommend that for stock engines.

2. 3.7L Magnum Stuck Lifters / Lash Adjusters

The 3.7 Magnum is a single overhead cam engine (SOHC). Because the camshaft in overhead cam engines is located in the cylinder head, they do not technically have lifters. However, the 3.7 Magnum does have hydraulic valve lash adjusters which function similarly to traditional lifters.

Lash adjusters are mounted in the head and are responsible for maintaining zero clearance between the cam follower and the valve, whereas traditional lifters maintain a small amount of clearance. Here is an article all about valve lifters in case you want to learn more.

In the 3.7L Dodge Magnum engine, the lash adjusters are prone to becoming stuck. Oil issues are the common cause of this problem. If you run oil that is too thick, or go a prolonged period of time without an oil change, the lash adjuters can fall out place. When this happens, the valve will get stuck from opening and closing which will cause major performance issues and other sporadic engine problems.

Symptoms of Stuck Lash Adjusters – 3.7 Magnum

Typical lifter tick engine noise
Cylinder misfires
Loss of power, lack of acceleration
Rough idling

Lash Adjuster Replacement Options

If you have a stuck lash adjuster the only replacement option is going to be to replace the lash adjuster. When this problem develops, it generally is isolated to one cylinder, so you can get away with simply repairing the single cylinder. However, if you our your mechanic is already down there, we would recommend replacing the full set. A single lifter will run about $10-$25 for an aftermarket brand or the alternative option is to upgrade to a high performance set which will run you closer to $100 per lifter but provide more reliability.

3. Piston Ring Landings

Piston heads have rings or grooves on them, as seen in the picture above, which are responsible for sealing the piston against the cylinder wall. These rings, also called ring lands, hold an airtight seal against the cylinder wall.

On the 3.7L Magnum or PowerTech, the ring lands have an inherent design flaw that causes them to produce excessive heat within the engine. In addition, the engine has rather small oil drain holes which further exacerbate the heat problem. Excess heat can break down oil, causing it to gunk up and get stuck within the engine. This is the main reason why the lash adjusters get stuck as we discussed in the previous engine problem.

Excessive heat can lead to numerous performance implications and also cause serious internal engine damage. Additionally, it can cause a number of other engine support systems to fail.

Dodge and Jeep Excess Heat Implications

Here is a list of problems that can occur when an engine is exposed to excess heat for prolonged periods of time:

Major metal engine components like the head, pistons, valves, etc. can warp, causing complete engine failure
Cooling system components like hoses, tanks, radiators, etc. can develop leaks and leak coolant, leading to even more engine heat
Oil leaves sludge in the engine causing lash adjusters to get stuck
Oil burns more quickly, leading to excess oil consumption which can cause internal components to rub against each other from lack of lubrication

I want to point out that this isn't an overly common problem.The severity of the problem usually causes it to be blown out of proportion on the internet. However, it has happened enough for leading companies, such as Powertrain Products, to call out Chrysler for the inherent issues. Chrysler has stood behind their engine throughout the complaints.

Powertrain Products suggests that this can occur as early as 75,000 miles on the 3.7L PowerTech / Magnum. Alternatively, we have read plenty of stories of these engines lasting well beyond 200,000 miles without any issues.

4. Positive Crankcase Ventilation (PCV) Valve

When an engine burns fuel it produces waste gases. Most of these gases are passed through to the exhaust system where they are further burned before flowing out of the exhaust into the atmosphere. However, some of these gases get trapped and can make their way down into the crankcase which holds oil at the bottom of the engine.

The PCV valve is attached to the crankcase and is responsible for releasing any excess gases that make its way into the crankcase. However, over time the valve can be gunked up from these gases and cause the valve to no longer open or vent the gases out.

When this happens, the gases get trapped in the crankcase which can gunk up the oil and make it sludge-like. When this happens, it can cause oil leaks throughout the engine and ruin seals, gaskets, etc. and lead to leaks through things suck as the valve cover.

Chrysler 3.7 Magnum PCV Valve Failure Symptoms

Rough idling
Loss of power, poor performance
Engine hesitation, sputtering
Poor fuel economy
Oil leaks (gaskets, seals, valve cover, etc.)

PCV Valve Replacement Options

Fortunately, replacing the PCV valve is a relatively inexpensive and simple fix. When you replace the PCV valve we also recommend doing an oil change to flush out any potentially bad oil within the engine.

The PCV valve itself is about a $15 part and can be DIY'ed by most people with basic engine knowledge. Here is a DIY video of the PCV valve replacement on a Ram 1500: https://www.youtube.com/watch?v=m-3j0JsHbvs

Chrysler, Dodge, Jeep 3.7L Reliability

The the Magnum 3.7L reliable? The engine, along with its 4.7L brother, don't have the best reputation on the internet. There are some serious issues such as the valve seats and lash adjusters that can cause catastrophic engine failure. However, these problems are quite as common as they might be made out to seem.

The biggest issue that causes problems on the 3.7 is excessive engine heat. Making sure your engine never overheats or runs hot is crucial to maintaining reliability. Change the oil frequently, flush the coolant per the recommended maintenance schedule and you shouldn't run into any catastrophic issues. Some items we didn't mention that are semi-common are things such as head gaskets and valve cover leaks, and water pump failure. All of these problems are caused by excess heat so preventative maintenance on the cooling system is key to maintaining reliability.

Some engines will report major issues as early as 75,000 miles while we have also read plenty of posts of the 3.7 Magnum lasting well beyond 200,000 miles and even into 300,000 miles. Overall, when properly maintained, these engine should be good for at least 200,000 miles.

If you are overly concerned about major problems, you can upgrade various parts of your cooling system, such as the radiator, to make sure excess heat doesn't plague your PowerTech.

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Source: https://tuningpro.co/dodge-jeep-37l-powertech-v6-engine-problems/