Curbside Tech: Replacing The Oil Cooler/Filter Housing On The PentaStar 3.6l V6 – Taming The Trail Of (Oily) Tears

A year ago.  That’s when I started noticing that our 2015 Jeep Wrangler (JK generation) was starting to drip oil at only 55,000 or so miles.  While in 2015 the Jeep powertrain warranty was good for 100k miles that only lasted five years, which was some time ago, hence now expired.  Crawling under the vehicle showed that the entire rear of the engine and the bellhousing was coated in oil and it was dripping from various end points.  Five minutes of research told me that it was most likely the engine oil cooler and filter housing and this part often goes bad in the 3.6l as well as the 3.2l PentaStar engines that Chrysler/FCA/Stellantis has installed (and still is installing) across their lineup.

Since the part is made of plastic, it apparently tends to warp, crack, and decide to unseal itself.  The replacement part is the same and will likely result in the same problem again eventually.  However, Dorman makes a replacement part cast from aluminum that is apparently good for the life of the car (as the original should have been).  I ordered one and then waited for the Jeep to come back to me last December when my daughter was going to be studying abroad and not using it.  Well, it’s been here all that time and next week I have to drive it back out to where she will be, so it was high time  I got off the couch and finally performed this repair. 

This is the Dorman part (Part #926-876, they actually call it the Oil Filter Housing, since that’s what they actually ship, you re-use the cooler part), it was backordered when I originally looked into it but eventually they made more and I received mine.  The housing is solid metal and quite nicely done.  While the original part (and the MoPar replacement part) comes with a few things that are attached to it the Dorman one does not, so I will transfer those over if they aren’t themselves the problem (doubtful).

Dorman does supply a set of new mounting bolts as well as all the gaskets, seals, and O-rings (well, one O-ring) that are needed for this job.  It’s a good time to also get a new oil filter and change the oil as a while you’re there type of thing even though it’s not really a time saver.  Conveniently for me, it was time for the Jeep to have that done anyway.  Wal-Mart actually stocks the factory filter (a cartridge one) for this engine so I got one from there along with the requisite 6qts of 5W-20 synthetic oil.

Note that some believe that a reason these fail is due to oil changes where the cap is overtightened.  The cap is at the end of the housing and twisting is can create a lot of torque on the body of the (plastic) housing itself.  The cap uses a 24mm socket to remove it (or whatever large wrench one has laying around) but only requires 18lf-ft of torque when replacing it, it’s not hard to overdo it.  Or for whoever changes your oil to overdo it.  That may then be the person you pay to fix this problem…Yeah I’m doing it myself from now on.

The first tool I dug out was my laptop.  I watched two videos on how to do this and then came across a third where this guy actually did it on the same model year Jeep we have and he was using the Dorman item as well, so this was perfect and necessitated another run to Harbor Freight to pick up a 27mm deep wall socket which I did not have.  The laptop went on my chest freezer in the garage a few feet in front of the patient, I just hit pause between every step while I did as instructed.  Monkey see, monkey do.

As an aside I’ve long been of the belief that if you don’t have the correct tool, just get it.  It’s almost always far cheaper to buy the tool than to pay someone else to have them use their tool.  You may be able to use it again.  And if not, you can almost always re-sell it for not much less than you paid for it.  For this job I used a variety of tools, the only ones though that I added were the socket as mentioned above and a small torque wrench that was able to measure in-lbs of torque.  I also picked up a clamping device for a radiator hose.  All of these cost less than $30 total and I’ll be able to use them all again.  Well, maybe not the socket, but it makes a good $4 paperweight.

A plus point of the Jeep Wrangler is that the engine is longitudinally mounted, very accessible, and the hood can open all the way back until it rests on the windshield header (with a towel to protect the finish, must continue to look good in the mall parking lot!)  The fenders make convenient resting points for tools as well.  After doing it, it may be quite easy in a transverse installation as well as you wouldn’t have to lean all the way back to the firewall I don’t think unless the engine is buried underneath it.  Either way, the process should be identical for any PentaStar engine, all of the following pictures bar one were taken from this frontal position.

Here the first step of the journey has begun with the removal of the engine cover.  It just pops up and off, then pulls forward to remove it from the rear tabs.

And we’re off!  That black spidery thing there is the intake.  The offending item is buried beneath it in the valley of the V6.  What happens it it will leak oil (and sometimes coolant) into that valley which eventually fills up (think of a mountain lake with a dam), and then eventually the oil rises and crests over the rear of the engine (like a spillway?) whereupon it just cascades over the rear of the engine and the transmission, gets blown along the entire undercarriage, and drips on the ground wherever and whenever it’s stopped.

It does sort of perform a “fluid-film” like service, undercoating the chassis with an oil bath, but there are better ways to do that.

The intake air duct needs to be removed using an 8mm socket or driver for the clamps and a 10mm for the two bolts holding it to the radiator support.

This engine is still caked in Nevada and Oregon dust from the summer trip a couple of years back but the next portion involves unclipping every electrical connector that’s connecting the intake to the rest of the engine or vehicle.  The lower plug was in the air intake tube, the MAP sensor plug just above it but below the throttle body has a little red safety tab that needs to be popped loose before the connector pulls off.

There are several vacuum hoses right at the top of the engine, another around to the right above the throttle body, and it’s also best to remove the one going into the airbox (or right under/next it anyway), these all just pull off once their seal of time has been popped loose with either a small prybar or a pick.  Or a screwdriver.  Pop them off, and tuck them as out of the way as possible.

This bracket that holds the AC lines in place is best to loosen by removing two 10mm nuts on the left and two 10mm bolts on the right side, this allows the bracket to be bent slightly to give more room later on as needed. It doesn’t actually come off in this case.

There are multiple hoses on the left side of the intake that have already been removed at their ends, now they can also be pulled free of their routing clips so that they too can be moved aside.  This is also on the left of the intake.

This large gray connector is in the same place and can also be seen in the two prior photos still connected.  The red tab pulls out, then the sides of the gray sleeve get squeezed, there’s sort of a cam lock that releases and the sleeve pulls forward and separates the connector.  Note the ribbed plastic wire sheath is very brittle, we’ll be revisiting that later, it’ll be falling apart a bit (and has already been doing so by itself).

The black part of the connector is fastened to the bracket (that’s the one with the two 10mm bolts that were removed a few steps back, you can see the front hole) using two plastic push pin things that can be pried loose with a door panel removal tool.  (A screwdriver handle on a rod with sort of a semi-circle pincer type end that wraps around things and pries them loose, cheap and a great tool that comes in handy all the time).

Moving back to the right, under and to the right of the throttle body is this bracket which needs to be removed, all 10mm hardware and easily accessible.  A wiring harness is also attached to it that needs to be removed with the removal tool.

Those two studs at the center is where the bracket was attached and it wraps around under the front of the throttle body where the two bolts were holding it on.  This wiring harness was attached to it with the clip at the top, looking left leads to the MAP sensor and the air intake pipe electrical connectors that were removed earlier.

There’s another bracket towards the rear right almost at the firewall in this case, the top 10mm nuts come off, easiest with a ratcheting wrench…

…and once those are off, there are two 13mm nuts lower down that are fiddly to get to but will loosen, they are to be loosened enough only so the top of the bracket can pull away from the studs as seen in the center.  In my case one of the lower nuts loosened, the other actually backed out the stud from the block, so required more caution.

So that was the appetizer, getting all loose and ready.  Once all the ancillaries are popped loose, unclipped, it’s time for the main course.  In this case, loosening the seven upper intake bolts, all 8mm.  Three on top as seen here, and four more along the left side with one buried in the back slightly under the firewall. These bolts are captive and pulling them up and rotating a quarter turn leaves them in the out position which is handy later when they’d otherwise get hung up.

The rear foam piece can be removed as I did by prying the two clips loose or better by pushing the edge back a bit to access the 10mm bolts that hold a small bracket that holds it on which is visible here still attached.  Removing it though gives access to the rearmost upper intake bolt as otherwise it’s buried in the foam piece, that bolt is visible in the lower left.  It was possible to loosen it with my 8mm driver but a socket with an extension or ideally one that can angle would be easy too (and better for tightening/torquing later)

Some wiggling, use of all four of your hands and the fingers growing out of your elbows keeps all the wiring and hoses out of the way while lifting this up and out.  It’s all plastic besides the throttle body so doesn’t weigh much.  It gets set aside for now, although you could clean up the bottom of the intake ports visible at the top of the image.  In my case I could not get the MAP sensor loose earlier, but once it was rotated like this it was easy.  Here it’s still connected at the bottom of the throttle body, I removed it immediately hereafter.

The red clip pulls out to unlock it, then I believe I squeezed the center of the black part and it came off.  If something doesn’t come off easily, there’s likely a locking clip or something that’s still connected, forcing things is not a good idea.  Better to do a new YouTube search to figure out the issue and solution.

Alright, halfway there, here’s the lower manifold in all its glory.  Note the oil filter cartridge cap in the center behind the alternator, that’s what we’re after here, everything below that.

The foam piece on the right just lifts off and should be stacked on top of the upper intake so that it isn’t forgotten later.

Something apparently made a nest in this one near the rearmost coil pack.  Hmm.  That obviously got removed now and there was no other evidence of anything similar or any other debris, just this.

It’s always a good idea to stuff the ports with shop towels or something just so you can find all of your sockets later.

Next it’s time to unclip the coilpacks on the right side only (three of them) and all the fuel injectors.  The coil pack connector just unclip with some squeezing but the fuel injectors have the red safety clips that need to be pulled up on before the connector can be squeezed and released.

It’s almost impossible to reach two of the three on the left but eventually after experimenting with a few different techniques they do release.  I used a right angle pick tool to pull up on the red catches which worked on most except for the rearmost right one when the catch disintegrated.  Since there was now no way to remove the plug I despaired for a moment and took a break.  Five minutes later I realized that I could just pivot the lower intake around that position, that particular one could stay connected.  This was probably one of the more difficult parts of the entire operation as it’s hard to get a good angle, difficult to see where the connector needs to be released with the pick and they are somewhat brittle.  I’m not going to worry about that injector, it’s fine for now and hopefully forever.

Earlier I mentioned the wiring loom covers that disintegrate, this picture is from the passenger fender side of the Jeep and the gray tube is my vacuum cleaner sucking out all of the plastic debris that has conveniently accumulated right next to the lower intake manifold.  Suck it out now or there’ll be regret later.  Repeat all around the perimeter as necessary.

Alrighty then, second prep phase is complete.  Now we are ready to get to removing the lower intake manifold.  There are eight bolts to be loosened.

Eight bolts, all 8mm, but with an option for a small torx it appers.  They loosen but are also captive.  The hole to the right and above the lower middle bolt is from where the upper manifold seats/attaches.

The ancillaries need to be dealt with creatively, here the big plug is just tucked up into the air to keep it out of the way.  The manifold is sort of pivoting on the rear right wiring that has the injector that would not release.  I used a small bungee to keep it elevated as can be seen here, it goes from one of the bolts to the inside of the hood.

Finally, my friends, we have reached the promised land, after hours of toil and a lot of ground covered.  Feast your eyes on the prize and reflect what it took to get here.  The PentaStar Oil Cooler / Filter Housing Assembly, unseen by man or machine since sometime early in 2015 in Toledo, Ohio! Glove up, it’s time to get in there, it’s been a lot of work to get here, I’m so excited!

This is the tool that is needed to remove the assembly.  There are five (only five!) bolts holding it on and they use an External-Torx (E-Torx) head, in this case an E-8.  I happen to own a full set of these and as I recall I purchased them to work on our last Mercedes, which is probably the era of Chrysler that this application dates to.  There is no really good reason for this bolt head shape to be used here, it’s a very low torque application and such positive engagement is overkill.  But anyway, I have them, and since it was a 1/4″ drive and I don’t have a long extension for that, I also have a small conversion piece that goes on to the back of the piece (or any 1/4″ drive) and converts it to a 7/16 head.  So I put this on the bolt, then use a 7/16 socket with whatever extension to make short work of them.

This picture also shows a most invaluable tool that I’ve had for decades and used more today than ever before, an extending wand with a strong magnet at the end from the days when I was still buying Hazet and other interesting (to me) tool brands before wising up and realizing that for the non-pro, non-paid work I do, Harbor Freight stuff works just as well.  It was useful for placing the socket on the bolt heads that were hard to reach otherwise and then removing it once I was done with my Rube Goldberg 7/16 conversion piece.

There are two sensors at the far end of the cooler, one for coolant and one for oil, both need to be unclipped either before or after removal of the cooler.  There is also a coolant hose that is clamped to the rear but I couldn’t reach the clip while it was in place.  I took a few minutes to plug these intake ports as well and clean up around the mating surfaces.

After unfastening the cooler, it needs to be rocked back and forth a little to release it (there’s an O-ringed fitting near the front) but it eventually just lifts up.  At that point I was able to get in there to undo the hose clamp after clamping off the hose itself (the hose clamp is visible at the top still in place).

There was a lot of oil and coolant in the valley as is evident here, I didn’t really anticipate that more would come out of the cooler, but of course it did and dribbled down there as well.  Lowering the assembly also resulted in a bit more coolant coming out of the holes in the block so I tried to keep it lifted up until it was well clamped.  I was under the impression I would lose coolant out of the hose but that didn’t seem to be the case at all, I think my clamping it wasn’t needed after all.  But any reason to use a new tool is a good reason, even if it doesn’t turn out to be necessary.

Here’s the underside of the assembly with some oil dribbling out.  This prompted me to place a towel underneath it, no need to add more to the mess in the valley.  Jobsite management starts to enter the picture here, as you can see the coilpack at the bottom and the lower intake manifold at the top, don’t want to dribble all over the coils and don’t want to jostle the bungeed manifold too much…lots of moving pieces here but slow and steady gets it done.

What a mess!  The spillway is at the back and having added to it, I quickly went to find my oil pan which I pushed under the Jeep to catch the new spills.  But all of this was just sitting in there.  Some people who are properly equipped can pump it out, but I just used a lot of shop towels, some normal paper towels, and a few rags.  Using a screwdriver (well, a Torx 30 in my case, it was closest to hand), I’d put a towel down and then use the screwdriver to push it into the deep recesses down there to soak up all that not-so-goodness.

Half an hour later it was looking pretty good! It turns out there are electrical connections down there under everything as well.  The two sensor plugs and the coolant hose were tucked up in the back to stay out of the way (and dry).

Off to the workbench!  (Okay, my chest freezer with a cardboard box on top).  Above is the new Dorman unit, below the OEM part dating to 2015.  It’s time to move some parts over after making sure they aren’t the issue.  Actually there was no obvious crack or break with the factory part that I could see, but it could be warped or have a minor crack that wasn’t visible to me.

This is the oil cooler part of the thing removed with its six bolts.

And here is the top of the Dorman piece with its two siamesed gaskets installed.

It just sits on top, there are two tabs so you can’t do it backwards, then it gets torqued down.

Here’s everything that’s getting put into the new one – A new oil filter cartridge with a new O-ring for the screw cap, and the two sensors shown in the middle right.  Both were a bear to get off, needing the 1/2″ breaker bar, one used the 27mm deepwall socket, the other a 19mm deepwall.  A little teflon tape around the threads should keep them nicely sealed after cleaning off the old residue.

The cartridge “pops” into the inside of the cap, and then when it gets screwed down seats itself properly at the bottom of the device, it seems to lock into place quite well.  I like top mounted cartridges, they are far less messy than most filters and the reusability of the holder is a good idea, assuming of course it doesn’t then cause issues such as this.

Here are both versions with all of the attachments transferred over to the Dorman unit.

The bottom used four new round gaskets (supplied) and an O-ring at the upper left which is slotted into its groove and lightly coated with oil to help it seat and seal.

It gets popped into the V focusing on the O-ring pipe that goes into its receptacle, and then the other parts just line up, the (new, supplied) bolts get dropped in and everything is torqued down in a specific sequence.

A full set of gaskets is included with the kit, for both the upper and lower sides of lower manifold.

So the old ones came out and the surfaces were cleaned up a bit….

…and the new ones went in, the port blockers were removed and it’s about time to put this thing back together.

It actually slotted in quite quickly and with less fuss than I was expecting.  The bolts just kind of dropped into their holes and then it was time to loosely turn them until they hit bottom.  Then torque in the proper sequence to the proper setting and replace the topside gaskets as well.

Now’s the time to carefully plug the coilpacks back in until they “click” and then the same with the fuel injector plugs, they “click” and then the locking red tab needs to be pushed down with a gentle tug back up to be sure everything is seated snugly.

The foam piece on the right side, now without the nest, gets popped back into place, the foam at the rear is pressed onto the upper manifold, and then the manifold itself slots back into place, this is easier with the bolts pulled out and locked into place so they don’t catch on stuff.  Extra fingers and limbs help to keep everything else out of the way, but once in place it’s time to again torque everything properly in the correct sequence, and then go around several times reattaching all the brackets, hoses, plugs, and wiring connectors that were undone before.

Finish things off with the intake pipe, remember the plug underneath it and it’s looking like it did several hours ago.

My wife snapped a picture of me working on the back part of the engine.  This is how I did a fair amount of the job – with one foot on the bumper, the other on the battery; some of the time I was standing on the bumper with both feet, and sometimes kneeling on it.  Access might be a little harder for some items with some other cars that you wouldn’t want to be stepping all over.

Here’s every tool I used on this job laid out on the “workbench”.  The most important tool was the laptop, without it I wouldn’t have attempted this job, but every tool had its place and job and was indispensable.  I only used the impact wrench to loosen the T30 nuts on the cooler but could have pre-done it while it was still in place, on the bench it was harder to get leverage so this was easiest.  Many people will use an impact wrench to remove virtually all the fasteners, I did it all old-school with manual tools except for that one instance.  Well, and the computer.

But we’re not quite done!  Since the oil filter was new and the drain pan was already under the Jeep it was a simple matter to undo the oil pan plug and drain it all out.  Then refill with 6qts of the new stuff, run it to check for leaks (none so far), turn it off, let it settle, and measure the level (properly full).

And it’s ready for me to drive it halfway across the country back to my daughter’s college next weekend.

I started this project (which means I opened the hood, not the prior prep) at 10:30 this morning and worked leisurely finishing around 4:30.  The videos all seemed to take about 22 minutes but that’s movie magic for you.  If I did it again I could shave a couple of hours off it, there was a fair amount of rewinding and rewatching certain segments to be sure I didn’t miss anything.

Overall this was one of the more intensive and difficult projects I’ve done in relation to a modern car, but as with most things, starting with a plan, the correct tools and parts, and a little patience goes a long way towards a successful ending.  I’ve linked the video that I used to do this below as it was remarkably complete, nothing was skipped over as with some of the others I watched and the creator worked at a methodical and easy to follow pace without making any assumptions as to the skill level of the viewer.   If you find yourself with a drippy PentaStar and can at least tell your left hand from your right, the cost of all of the tools combined is far less than paying someone else to do this job.  A dry, safe place and most importantly the time to do the work of course helps tremendously.