How One Faulty Engine Part Put Millions Of Chryslers, Dodges, Jeeps, And Rams At Risk Of Major Oil Leak

The Pentastar V6 has been a workhorse for Chrysler. Since its introduction in 2011, over 10 million have been built, and they’ve shown up in everything from minivans to trucks to sedans to coupes to offroaders. The only problem is that Chrysler cheaped out on one crucial component that has irritated owners to no end. Worse, this silly little flaw puts the whole engine at risk.

It all comes down to oil. As we all know, the engine cannot run without it. Given its importance, you would think Chrysler would have done everything it could to make sure the engine’s lifeblood stays inside the crankcase where it needs to be. As it turns out, the company kinda messed up on this crucial detail.

Whether you talk to forum users, NHTSA, or mechanics, the answer is the same. This one cheap plastic part afflicts Jeeps, Rams, Chryslers and Dodges alike. It’s got them spilling oil, and badly—with nasty consequences to boot.

However, this engine has lots of other applications too. You’ll find the same engine in Jeep Gladiators, Ram 1500s, Chrysler Pacificas, and Dodge Durangos, just to name a few. Ultimately, this is a problem that affects just about every 3.6-liter and 3.2-liter Pentastar V6 in the Stellantis fleet, including those built today.

A Slippery Situation

This oil leak problem came to our attention while researching the Pentastar Tick issue on the NHTSA complaints database; we noticed that so many more folks were complaining about the oil cooler. Seriously, look at these complaints, and you’ll realize just how shocking the scale of this problem is:

These engines feature a combined oil cooler and oil filter housing that is bolted to the engine. The oil cooler is plumbed with coolant to keep the engine oil at a stable temperature. From there, oil then flows on to the filter section—a simple housing for the replaceable cartridge oil filters.  The part is naturally plumbed with coolant and oil, and also plays host to the oil temperature and oil pressure sensors.

So far, so simple. The problem is that Chrysler made one choice that seriously compromised these parts. The whole part is made out of plastic. That’s not such a problem when the vehicle is new. The plastic, likely nylon reinforced with glass fiber, is able to hold up to hot engine oil without issue. However, aging is a real killer when it comes to components like these. Repeated heat cycles and the simple passage of time make the plastic brittle and weak over time.

Eventually, cracks form in the plastic, and you get a major engine oil leak. This can often happen during an oil change, particularly if the oil filter housing is overtightened during reinstallation. The oil filter cover is only supposed to be torqued up to a mild 18 foot-pounds. It’s relatively easy to exceed this, with damage to the plastic parts a likely result.

Thanks to the position of the part, most of the oil ends up running into the valley of the V6. From there, it then drips down the back of the engine and transmission and on to the ground. It’s easy to mistake the leak for a worn engine rear main seal because of the location the leak appears on the ground. Ideally, though, the leak is caught quickly and the part can be replaced. However, in some cases, the part can fail while the car is running and dump a lot of oil very quickly. In this case, the engine has to be shut down quickly before the oil supply runs completely dry.

Other failures are possible, too. If the plastic cracks or breaks around the oil cooler section, a coolant leak may develop instead. Or, even worse, a failure in this area can lead to coolant and oil mixing, which is similarly awful for the engine.

The plastic doesn’t have to crack to cause problems, either. Sometimes the housing just warps over time and stops sealing properly in various locations. Alternatively, the O-rings sealing the part to the engine block start leaking, or the plastic lip holding them in place just falls to pieces.

Owners can be found complaining about this problem all over the Internet. Wrangler Forum has a whole cavalcade of posts, with owners reporting oil leaks, coolant leaks, and oil ending up in the coolant reservoir. You’ll hear the same from owners of the Chrysler Pacifica, Dodge Durango, and even the Volkswagen Routan. Yep, since it’s a rebadged Chrysler, it came with a Pentastar, too.

[Ed Note: These complaints are rampant with early Pentastar engines, but they appear to be less prevalent with the “Pentastar Upgrade” that came around 2016 in some products. The “Pentastar Upgraded” entered the Wrangler when the JL model came out; there are some oil filter housing complaints with the JL, but they seem significantly fewer than on JKs. Maybe this has to do with miles driven, but it’s worth noting that significant engine redesign. -DT]. 

NHTSA has received some harrowing complaints. One owner reported a “small fire” occurred when leaking oil came into contact with the hot exhaust system. Others have reported having to replace the parts three or even four times in under ten years of ownership.

It’s easy to understand why people are pissed off. We expect to change our oil and oil filters regularly, that’s just normal automotive maintenance. The oil filter housing, though? We kind of expect that to be a hardy part of the engine that lasts for the lifetime of the vehicle. The fact that the part can fail quite easily within a few years of ownership, and potentially lunch your engine in the process? That’s no bueno. The fact that simply overtightening the filter cap can destroy it in one misguided tug of a wrench? That’s pretty annoying, too.

The Fix

Swapping out the part is not the easiest job, either. It requires removing the entire upper and lower sections of the intake manifold in order to gain access to the valley of the V6. From there, the part can be unbolted and lifted off the top of the engine.

Guides on how to manage this problem are all over YouTube. David from the MotorCity Mechanic channel notes that there are two main routes to fix this problem with OEM parts. You can either replace the whole housing, or start by just replacing the set of O-rings that seal the part to the engine block.

Solely replacing the o-rings is the cheaper route, but not a guaranteed fix. “That’s just something that at the dealership we would have to struggle with,” David explains. “In order to get paid for warranty, Chrysler said we had to do [the o-rings] first.” If that fix failed, the whole housing would be replaced, at greater expense.

Either way, neither of these methods is a permanent fix. You can expect the replacement housing to last maybe as long as the original OEM part. Perhaps less so if it’s subjected to heavy-handed techs during your regular oil changes at your local Lube-E-Mart.

Eventually, however, a better repair became available from the aftermarket. Well-known parts company Dorman started manufacturing an all-aluminum version of the oil cooler and filter housing. It solves the plastic problems with good old fashioned metal.

The redesigned part eliminates the problem of embrittlement and cracking over time, as well as collapsing lips that hold the o-ring seals in place. It also solved the problem of block-off ports blowing out by using proper threaded plugs with sealant holding them in place. The Dorman part is made with high-pressure aluminum casting techniques.

You have to pull a lot of parts off to get down to the oil filter housing. It’s not necessarily a super difficult repair, but it’s time consuming to a greater or lesser degree.

The Dorman part is intended to be a one-stop fix for this problem. To that end, it’s shipped with a full set of seals. This includes the seals for the upper and lower intakes that need to be replaced when removed to execute the repair.

The core aluminum housing is just a replacement for the plastic part. In Dorman’s original design, the sensors and oil cooler itself had to be swapped over from the original OEM housing. This created compatibility issues—early Dorman parts were designed to suit the oil cooler from post-2014 Pentastar V6s.

However, Dorman now provides an updated version that comes with an oil cooler of its own that works with earlier Pentastars, too. It updates any Pentastar to work with the more modern post-2014 oil filter design. Either way, there have been a few revisions over the years, too, so it’s important to make sure you get the right Dorman housing to suit your particular vehicle.

As you might expect, there’s a reason Chrysler didn’t go this route in the first place: Cost. Making the part out of plastic was a great way to go—it’s far cheaper than machining the same part out of aluminum. As long as the part doesn’t fail too often during the warranty period, the savings are worthwhile. Plus, the cynics will suggest that it’s a great way for Chrysler to make some money on parts on the back end.

If you own one of these Pentastar powered vehicles, you can make the call yourself. If you go with the plastic OEM part, the official Mopar replacement part costs around $170. You might find it cheaper if you hunt around the place. I found another part for around half that price from an Australian seller, though it’s likely not OEM grade and doesn’t appear to come with any seals. Meanwhile, the Dorman part comes in around $202 on what appears to be Dorman’s official Amazon store—and that’s including all the intake seals, an oil filter, and a new oil cooler to boot. It’ll cost you a little more from Advance Auto Parts, which currently has it listed for $308.99, or $262.64 with a coupon code.

Given the relatively minor price difference, it’s easy to see the appeal of switching to an all-metal replacement part. Oil leaks are a pain to deal with at best. At worst, they can trash an engine or set your whole car on fire. If you have to get in under the intakes to fix one, better to do it once and be done with it for the foreseeable future.

Why Is Everything Like This?

Unfortunately, problems like these are pretty common in modern vehicles—and modern technology across the board. It all comes down to money. Engineers are seldom tasked with designing for the best longevity or performance. They’re generally told to design vehicles that can be produced with excellent profit margins. If a plastic part is cheaper and lasts long enough, forget metal—it’s not happening.

Chrysler isn’t the only one playing this game. BMW’s cars are famous for using cheap plastic parts in the cooling system. GM has done much the same. There are a million other examples out there. Parts that would never fail on a classic car from the mid-20th century are now regular replacement parts on modern engines. [Ed Note: My experience at Chrysler was that engineers would have run tests on all parts, and had they seen a concerning failure, they’d have fixed it to avoid warranty costs. I’m a bit perplexed by the fact that this failing part remained in production for years and years despite numerous failures. -DT]. 

The trick is to be aware of the cheap, crappy parts on your car. That way, when one fails on you, you’re already educated on what’s broken and how to fix/upgrade it, before you end up as a giant ball of fire barreling down the highway. Stay safe out there, and maybe share today’s post with your poor Pentastar-owning friends. Though I bet they already know all about this.

Image credits: Jeep, Ram, Stellantis, Chrysler, Amazon, Dorman, MotorCity Mechanic via YouTube screenshot, ATEM Offroad via YouTube screenshot, Maxspeedingrods