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Discussion Starter · #1 · (Edited)
Hi There,

New forum member here. I plan to replace the head gaskets on my 2013 Jeep Wrangler 3.6. While I am an experienced former tech, I have some questions about the job and the parts.

In case folks are curious, the Jeep has ~85,000 miles on it and it runs fine. The symptom is that coolant overflows into the coolant tank and does not get pulled back into the engine. No bubbles in the radiator and no burning coolant out the tail pipe (I know that distinct smell well). The coolant overflow and the radiator do smell of exhaust once you take the caps off and a block tester confirms the issue (blue fluid turned yellow). I plan to skip the cylinder leak down test and plan to replace both banks. I am aware that bank 1 (passenger side) is more difficult and requires pulling the timing cover. I plan to replace the head gaskets, head bolts, rocker arms, front cover gaskets and maybe the lifters. My Jeep is a January 2013 build and the Julian date code on the bank 2 head puts me out of the affected range for loose valve seats.

Anyway, here are my questions. Thanks in advance for any advice.
  • FelPro makes a head gasket set and head bolts for this engine. Is there any reason to go Mopar over FelPro on these parts?

  • I have the factory service manual but cannot find a specification listed for shaving the head. Can the Pentastar 3.6 heads be shaved a little to bump compression?

  • Is there any reason to replace all the HLAs at 85K miles unless there is a symptom? From what I understand, this part has not been updated, unlike the roller rockers. I know how to check them individually - just wondering if they should all be replaced as preventative at this mileage.

  • Since I will be pulling the front cover and messing with the timing chain anyway, is there any reason to replace the timing chain at 85K miles? I saw a video on YouTube of the tear down of a 600k mile Pentastar 3.6 out of a Promaster. There seems to be a few kits available, ranging in price pretty widely from ~$160 to $840 or so for what appears to be the same parts.

  • Does anyone know the Mopar book time for replacing both head gaskets on a 2013 Wrangler (JKUR) with manual transmission? Interested in the warranty book time, not the customer pay time out of the Chilton guide. :)
Thanks in advance. Appreciate any responses.
 

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KOG
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You don't want to mill heads any more than necessary to flatten then, better if you don't have to mill them at all. With OHC milling the head affects valve timing and the compression is already about as high as you can get away with.
 
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The head gaskets should be MLS (multi layered steel) for better sealing. If that is what Felpro uses, they should suffice, head bolts are a must because I believe they are torque to yield, which are used by just about everyone these days. Clean the head surfaces and don't worry about raising compression, as noted, OHC engines have issues with that and adjustable cam gears makes for expensive or not available issues.
 

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Welcome!!

Subscribed and wishing you great success and hoping you post on your progress.

Wife has a 2011 Chrysler 200, 3.6 and I'm learning what I can from others experience.

I have watched several 3.6 you tube vids for information and expect you have as well.

One guy in comments claims he removed both heads with out removing the front cover?

I experienced the 3.6 tick and found 1 bad rocker on bank A and replaced all on bank A

If possible could you post the cyl. head bolt torque values and sequence from your FSM.

I've heard of different procedures including tightening, loosening then re tightening.

Most interested in what the FSM recommends.

I just checked on RockAuto for head gasket info. and was surprised.

Most run close to $40.00 but the left only Mopar (5184455AI) was under $10.00!

Best of luck !!!

Thanks
Randy

Jeff Lemke commented on "JEEP jk 3.6L Headgasket replacement What not to do" vid.

"I had a chipped intake valve on the passenger's side. I was able to get that singular torxs head bolt off by taking the very tip of a torxs bit and welding it into a tiny box wrench. Then ground the tool thin enough to loosen the bolt, then needle nose vice grips to back it out. Make sure to stuff rags down the timing chain openings to prevent anything from falling down. I placed a magnet on the head of the bolt and used a stubby hacksaw blade to cut the head off then finish extracting the body of the bolt. If anyone tries this, be super diligent to prevent any fillings from getting down the timing chain openings. Also keep any magnets away from the cam phasers. My favourite part for reassembly was using a slightly shorter hex head bolt for the chain guide bolt that was cut. Now a standard open ended wrench can be used. It took about an hour, but I was able to avoid the removal of the front timing cover."
 

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Discussion Starter · #5 ·
The head gaskets should be MLS (multi layered steel) for better sealing. If that is what Felpro uses, they should suffice, head bolts are a must because I believe they are torque to yield, which are used by just about everyone these days. Clean the head surfaces and don't worry about raising compression, as noted, OHC engines have issues with that and adjustable cam gears makes for expensive or not available issues.
Yes, the Felpro gaskets are multi layered like OEM. If they are different, it might be in the sealing ring around the cylinder. The head bolts are torque to yield and I do intend on replacing the Felpro offers a replacement set. of bolts as well.


 

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Discussion Starter · #6 ·
Welcome!!

Subscribed and wishing you great success and hoping you post on your progress.

Wife has a 2011 Chrysler 200, 3.6 and I'm learning what I can from others experience.

I have watched several 3.6 you tube vids for information and expect you have as well.

One guy in comments claims he removed both heads with out removing the front cover?

I experienced the 3.6 tick and found 1 bad rocker on bank A and replaced all on bank A

If possible could you post the cyl. head bolt torque values and sequence from your FSM.

I've heard of different procedures including tightening, loosening then re tightening.

Most interested in what the FSM recommends.

I just checked on RockAuto for head gasket info. and was surprised.

Most run close to $40.00 but the left only Mopar (5184455AI) was under $10.00!

Best of luck !!!

Thanks
Randy

Jeff Lemke commented on "JEEP jk 3.6L Headgasket replacement What not to do" vid.

"I had a chipped intake valve on the passenger's side. I was able to get that singular torxs head bolt off by taking the very tip of a torxs bit and welding it into a tiny box wrench. Then ground the tool thin enough to loosen the bolt, then needle nose vice grips to back it out. Make sure to stuff rags down the timing chain openings to prevent anything from falling down. I placed a magnet on the head of the bolt and used a stubby hacksaw blade to cut the head off then finish extracting the body of the bolt. If anyone tries this, be super diligent to prevent any fillings from getting down the timing chain openings. Also keep any magnets away from the cam phasers. My favourite part for reassembly was using a slightly shorter hex head bolt for the chain guide bolt that was cut. Now a standard open ended wrench can be used. It took about an hour, but I was able to avoid the removal of the front timing cover."
Thanks for the welcome!

Yeah, I've seen a bunch of videos and really like those from David, the MotorCityMechanic. I believe what you are referring to is that you can pull all four camshafts and do the roller rockers properly without removing the front cover. You need some special plastic tools (wedges) to keep the cam chain tensioners from opening all the way. To get the bank 1 head off, there is a bolt on the front of the head that can't be accessed without pulling the cover.

I plan to buy more than just the head gaskets. You can buy a "head set" which is everything you need for the job and includes the front cover gaskets.

I've had the intake torn down on this jeep before. I installed an Edelbrock supercharger kit on it and then water methanol injection. I have since removed it all and returned to stock. Not a difficult engine to work on in a Wrangler.
 

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KOG
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Ah, a supercharger. Now we have an idea of why the head gaskets suffered.
 

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Discussion Starter · #8 ·
Ah, a supercharger. Now we have an idea of why the head gaskets suffered.
Thanks for the commentary. Sorry, I'm not someone who really buys that. I'm not a believer that an aftermarket forced induction kit would necessarily lead to head gasket failure on a modern engine. I have a lot of experience with forced induction and that particular kit was a well designed, low pressure kit. There are plenty of supercharged jeeps out there without head gasket issues and there are also non supercharged jeeps with the same issue as mine. Here is one example that I found:

If any of the aftermarket modifications had anything to do with the head gasket failure, I would point the finger at the water/methanol system that I mentioned above. I could see where the corrosive properties of the methanol eroded the sealing rings around the cylinders on the gasket. I have yet to do the "tear down and inspect" so no clue yet where exactly the failure is.

There's a company out there pushing the limits and producing higher boost turbocharger kits for these engines. In the higher boost engines (12psi and above), they are finding that it is the head bolts that stretch and not the gaskets failing as a result of the gasket itself. For that, there is the option of using stronger, non-TTY head studs with the stock gasket.

The biggest problem to worry about when running a supercharger or even just high compression is detonation and a proper tune will take care of that on top of things like an intercooler and water, methanol or water/methanol injection. In other words, you are more at risk of burning a hole in the top of one or more pistons than blowing a head gasket.

It would be great if you have the answers to any of my questions. That would be helpful. Thanks in advance.
 

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KOG
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As you noted, the bolts stretching did contribute to the gasket failure. Not that the gaskets might not hold it. And your diagnosis of detonation being a real problem would also be correct. Detonation can cause all sorts of failure without any additional boost. And you are on top of this. Why'd you remove the blower?
 

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Discussion Starter · #10 ·
As you noted, the bolts stretching did contribute to the gasket failure. Not that the gaskets might not hold it. And your diagnosis of detonation being a real problem would also be correct. Detonation can cause all sorts of failure without any additional boost. And you are on top of this. Why'd you remove the blower?
Detonation is bad. I've read about someone who installed the supercharger but the technician didn't get the tune installed properly and the engine destroyed itself in less than 20 miles as I recall.

Perhaps the head bolts stretched. Prodigy Performance reports it to be a problem at 12psi and above. This was a 8psi kit.

I removed it because it runs better offload on the technical stuff without it. I've run the Rubicon many times as well as other trails in the area. I've run data logging too. Almost no boost is logged while off road for what I do. Getting up to the mountains on the highways is another story. There was definitely better passing power with the blower. The blower was also metal and would heat soak. Een with one ton axles and 40" tires, I still prefer NA to FI off-road. Something like sand dunes, might be another story. I could see being on more boost for that.
 

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Discussion Starter · #11 ·
Anyway... I decided to order all Mopar parts, including new heads. Factory remanufactured heads are not that expensive.

I am thinking to possibly replace the primary and secondary timing chains as well as the harmonic balancer too.
 
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