AZJeff

I actually have the Liberty shop manual, and to measure chain wear as described above, you have to remove the Timing chain cover and all the crap in front of it.🙁 once I am that far in on a 120k engine, I AM putting new parts in.

Just in case you are wondering why I am concerned about the camshaft drive system on the 3.7L engine: My son has a Ford F150 with the infamous 5.4L Triton engine with the VVT. These things are NOTORIOUS for having the "cam phasers" that control valve timing dying and causing catastrophic valve train damage. In addition, the chain drive wears inordinately, and can cause chain jump because the tensioners cannot accommodate gross chain stretch. Owing to this, we decided to be proactive on his truck at just below the 200K mark. (Many of these engine croak LONG before this due to this valve train problem.) Because my son had been VERY diligent about oil changes and using synthetic oils, the valve train was still functioning, but there was no doubt that the chains were getting sloppy, and it was inevitable that the system would die in a catastrophic way in the not-too-distant future. We dodged a bullet by doing the cam drive system proactively. Parts were not cheap, but they were cheaper than a new/used engine. I just want to make sure the 3.7L Jeep engine doesn't have a similar latent defect in the cam drive system as does the Triton, and this is why I asked the question.

I figured you might have some intelligence on this. That would be appreciated if you could check the library..

Its been living on Mobile One, changed every 4-5K miles since new. I changed the valve cover gaskets last year, and the top end was a clean as could be, so I guess the change intervals and oil choice is doing it's part.

My wife has a 2004 Liberty that we have owned since knew. It has 121K miles on it, and it runs just fine, with no issues...no noises, no leaks, no oil consumption. However, I know that the 3.7L engine in the vehicle has timing chains the drive the camshafts, and these are tensioned by oil pressure driven tensioners. I am seeking some advice as to when it would be considered prudent to replace these chains and tensioners. Since this is an "interference" engine, I don't want to wait until a chain jumps time and trashes the engine. Can anyone point me to a reliable source as to how long this valve train can go before it should be replaced. Thanks.

That's what I am used to seeing. I guess just because a diff. has LSD does NOT mean it will look like all other diffs with LSD. Everybody who makes an LSD carrier does them a little differently.

I guess I learned something new. I always assumed the normal LSD looked something like the attached photo inside. I guess I was wrong, and there is more than one way to make an LSD, and some of them don't show the clutch packs so obviously.

That must be some aftermarket design you describe, as I have never seen an OEM diff. with that configuration.

You can see the clutch packs (partially) in an LSD housing. Those are not present in the photos, so that is a traditional "open" differential.

The method you suggest is commonly used at professional shops to find leaks in an auto AC system. The system needs enough refrigerant in it to cause the compressor to cycle. Once that happens, the dye that is added into the system is then used with a black light to find the leak(s). If the leak is in the heater box (due to a bad evaporator), the only way to find that is with a refrigerant "sniffer", but I am betting you will find it via the dye and blacklight.

There is no reason to replace all of the components in your system if you convert to R134a. There is another thread on this topic that is active right now where I make some suggestions on what needs to be done

The Chiltons and Haynes manuals are marginally useful, at best. The ONLY real way to go for a service manual is the factory one.

I normally buy stuff like the receiver/drier from a reputable place like Rock Auto. At least that way, you get some decent brand name stuff. The O-rings can be had at virtually any auto parts store, as can the oil. The later Sanden compressors use PA100 oil. I don't know what the older ones use, but lacking any other suggestions from the forum, I would assume the PAG100 would be acceptable.

The conversion to R134a should not be very expensive, especially if all the existing system parts are in good working order. In fact, I would say it would CHEAPER to convert than to stay with R12. Having done several conversions, here is my advice: If your existing hoses are all in good condition, with no cracks or dry rot, they can be used as is. However, ALL of the o-rings that join those hoses to the various parts of the system will need to be replaced. The old o-rings will be dried out and are likely to leak with the smaller molecules that are present in R134a. The condenser and evaporator can be reused. If you want optimum performance, it would be beneficial to flush those two items with a refrigerant flushing agent, and blow them out with compressed air while they are disconnected getting new o-rings installed. The idea behind flushing them is to try to drive out as much of the old R12 compatible refrigerant oil as possible. It's not harmful to leave it in the system, but the old oil will reduce system capacity and function to some degree. I would recommend taking the compressor off and draining as much of the old oil out of it as possible for the same reasons you want to flush the condenser and evaporator. Installing a new receiver/drier (accumulator) is a must. This item has a dessicant in it that is probably long since used up, and since you have the system apart, it has probably sucked up some more moisture during that process. When you fill the system with new R134a compatible oil, you should fill various parts of the system based on this ratio: 1. the accumulator gets 50% of the total oil for the system 2. the condenser gets 12% of the total oil for the system 3. the evaporator gets 25% of the total oil for the system 4. the compressor gets the remaining oil I don't have the numbers for how much oil your model year takes, unfortunately. As far as how much R134a refrigerant to use, the rule of thumb is to fill the system with 80% of whatever amount was supposed to be used when the system was charged with R12.

Unless parts of your existing system are damaged, worn, or missing, there is no reason you have to replace all of the pieces when converting to R134a. The heat exchangers in the system (evaporator and condenser) would probably benefit from a flush. The existing lines will probably be oil soaked with R12 oil, so they will provide enough of a barrier to prevent R134a molecules from leaking through the old "non-barrier" style hoses. Changing the accumulator (receiver/drier) is HIGHLY recommended, of course. You will also need new R134a compatible oil for the system.

A stethoscope will help you isolate the location of the noise in the engine. Some of the conditions you describe sound like pistol slap might be the source. Since the 4.0 engine uses pretty short skirts on the pistons, and this can contribute to creating slap. That said, slap, while annoying, can exist for many thousands of miles without any significant issues. A compression test can help to determine if the piston to bore clearance is just enough to create slap, or bad enough to lead to oil consumption issues, etc.

OME shocks are excellent items, assuming you can find ones that fit the MJ correctly. (The fronts are the same as an XJ, so that won't be a problem. The backs, which are unique to the MJ, are the challenge.)

Very nice adaptation👍

If the plastic rods cannot handle the steady strain on the, some all-thread rod would CERTAINLY be up to the task.

If you lived in AZ, I would be glad to help. NC is a bit far away for a quick road trip.

Punctuation would make this easier to read/understand. Let's start with what the manifold leaks can do: 1. leaks on the intake ports will confuse the MAP sensor, and that will mess up mixture. 2. leaks on the exhaust ports will cause the cat. converter to get erroneous combustion mixture, and send erroneous information to the PCM. The manifold gasket design on the 4.0 is prone to leakage. I recommend you spend the money on a "Remflex" gasket, as it compensates for the issues the OEM design fails to do. There are three bolts that are used on the 4.0 that hold ONLY the exhaust manifold. There is one at each end of the head, and one in the center at the top near the throttle body. ALL the other bolts due a shared job of holding both the intake and the exhaust manifold onto the head, using special conical washers. This means you can remove all of those bolts and take off the intake by itself, and then focus on removing the three exh. manifold bolts separately. This is important because the frontmost and rearmost of the manifold bolts can be tough to get out. (They are actually nuts on studs, BTW.) To address these, you will want toSOAK those two nuts with a bunch of penetrating oil before you try to remove them. PRO TIP: I find trying to line up the bolts with the conical washers on them when reinstalling the intake manifold to be a HUGE exercise in frustration. I replaced all those bolts with studs and nuts (and reused the conical washers.) A helper to align the manifold when installing them make the job easier, so offer your buddies some pizza when it comes time to put it back together.

You say you have spark. How as that verified? Did you test every plug and every plug wire? What does the rotor/cap look like? And may I suggest you borrow a vacuum gauge from somewhere and test your idling vacuum.

I doubt that spring was ever available as a replacement part unto itself. You can probably create a functional replacement from some stock spring purchased at a decent hardware store. You might have to cut it to length and bend the ends to make the appropriate "tails" on the spring.

The FSM vacuum diagram should work out OK. One thing you can do is to blow into one end of a given vacuum hose, and have a helper see if the other end sees an output. Of course, one needs to know the names/locations of the various items connected via vacuum to verify that some previous owner didn't make mistakes reconnecting stuff. That might be worth a check.

Carbon fouling is an indicator poor combustion. With the misfires you are seeing, that might be a contributor. However, it takes more than just good plugs to make a good ignition. When you say "I have a plug tester so that's all good", does that mean that the light in the plug tester shows consistent spark on each plug? Rough idle is caused by inconsistent combustion, and that can be caused by a bunch of stuff, but ignition is the first place I always look. I also talked about vacuum leaks in my other message. Do you have a vacuum gauge?