AZJeff

The 1999 engines have an improved crankcase vent hose and valve cover that deals with blow by much better.

Loss of the oil cap opens a HUGE leak to the crankcase, which is pressurized to at least some degree on a perfectly working engine. The fact that oil loss drops dramatically without the oil cap tells me a couple of things: 1. Your engine may be quite tired and venting lots of combustion gases past the rings into the crankcase. 2. Your crankcase vent system is not working as designed by Jeep. With the cap in place, it is sealing the crankcase up to a level that the malfunctioning (plugged) crankcase vent system can not deal with. I would run a compression test on the engine to get an idea of how much blow by the rings are allowing to enter the crankcase. I am guessing you have a tired engine spewing lots of blow by gases, and a compression test would affirm or refute that. In addition, I would do the upgrades to the older 4.0 valve cover and crankcase vent system. This will help vent a tired engine more effectively.

I will be odd-man out here: I have run all-metal CSF versions in my previous XJ and now my MJ, and I live in S. AZ, so it’s a high stress environment. I have no issues.

My fittings are nice and clean, in terms of corrosion. It's one of the benefits of living in AZ. I probably would have to spray them out with brake cleaner or the like to get any dust/dirt out of the fitting, but otherwise, they should be good to go. So if I squeeze the two plastic "ears" on the connector together, and pull on the hard line, it should slide out of that fitting that is screwed into the side of the transmission case, correct? And then that hard line has some o-rings and a plastic spacer that seals the connection when it is reinstalled, correct?

I have a leak on one of my cooling lines to my AW-4 where it enters the transmission housing. From the reading I have done on the topic, everyone was recommending replacing the quick connect fitting that screws into the transmission case, along with installing new O-rings on the hard lines where they join this quick connect fitting. There is just one rub---the recommended quick connect fitting from Dorman that screws into the transmission case is no longer available. Does anyone have suggestions on how to stop this leak without winding up using AN fittings and braided hose to replace the hard lines?

I went digging through my 1990 and my 1987 FSM, and cannot see any details about what that valve does as it is related to the accumulator. In fact, they don't even really have a diagram showing the "theory of function" for that AC system, so that added port has me mystified. Maybe someone else who is more attuned to the older (and much less efficient) AC systems can explain what that friggin valve is for.

I think some investigation into the operational theory of that version of AC is warranted before I can declare that valve's purpose. Time to dig around for the FSM for a 1987.

I am a lazy @$$. I buy the connectors with pigtails already attached, and then crimp/solder/shrink wires on to the connector pigtails to make my harnesses. Your method is more elegant, but requires the added tools to crimp, plus the special tools to remove a connector pin if you screw up and need to replace it.

The wiring for the back of a Comanche is so simple that one can make their own harness pretty easily. I chose to use an AMP weatherproof connector, but a Deutsch weatherproof type would work equally well both where the wiring leaves the cab, and where it spreads out for the various sockets. SOLDER all of your connections, and use adhesive lined heat shrink, and you should be good to go.

Those "spring parts" you show look like service port (filling) valves. Can you show a picture of where these are installed in your system? I might be able to answer better that way.

That looks like it will do the trick. Let us know if that fix is permanent

If anything attaches to that threaded stud, it would prudent to somehow figure out a way to distribute the forces that said stud will apply to the epoxied joint, which will mostly be in tension. Since the area of the bonded joint is small, the epoxy has to work pretty hard to keep the joint glued. The best solution would be a combination of adhesive both on the outside and INSIDE, but since that means disassembling the heater box, that isn't probably in the cards. The attached is my suggestion on how to do the best possible bond without having to take the heater box apart and still get a good strong joint. AAA.pdf

I have never seen duct tape that thick, but I am not an expert on that stuff. The idea behind the aluminum is to help keep the crack or hold from expanding, and the epoxy becomes the agent to bond/seal the aluminum to the existing resin HVAC case.

It’s actually probably “macro blend” which is a PC+ABS blend. And like I mentioned, it’s mineral filled to enhance rigidity. Depending on the type/length/location of the crack and/or hole, an added reinforcement of aluminum sheet about 0.025” thk. would be beneficial.

Can you send a picture of what the damage looks like? I can make a better suggestion on how to best repair it so that it's more or less permanent.

If we are talking about the actual heater box proper, it’s going to be of a resin that won’t deform under the temperatures seen around the heater core, which are going to be about 200*F. That rules about polypropylene or polyethylene. It might be ABS, but it’s also mineral filled, to increase its stiffness. Epoxy should work. If the damage is extensive (long crack or a hole), a piece of thin aluminum laid over the damage and bonded with the epoxy would be prudent. (A few “pop” rivets through the aluminum/plastic sandwich to help position the repair would also help. I have done this on other ABS parts such as old dashboards in the past with good success.

I don't quite understand your question. The timing cover is attached to the engine block with a bunch of small bolts that go around the perimeter of the cover and also join the cover to the oil pan. As long as these cover bolts are not loosened or removed, the cover's relationship with the crankshaft will remain untouched, and the concentricity of the balancer to the seal in the cover will be unchanged, thus insuring the seal will do it's job. It's only when someone removes or loosens the cover, and then does not realign it with the center of the crankshaft that we get into issues where the seal does not contact the surface of the balancer evenly, and it begins to leak oil.

I am building a new short block for my MJ, and have found a couple of variations between what engine is in the vehicle now, and the one I am assembling, and this made me wonder about these small differences. I wonder if any of you AMC gurus would know the reasons for these: 1. Cylinder Head Dowels my existing engine that I am replacing is from a 2000 XJ. The cylinder head is located to the block with two dowel pins. My replacement engine block is from 1992, and does not have the dowels nor the holes for dowels. Does any one know why they added the dowels on later engines (aside from the obvious convenience when installing the head)? 2. Timing Chain Types my existing engine has a "silent type" timing chain and sprockets. The new chain my engine machine shop recommended is a traditional "roller" type. I know that AMC used roller types in the past, but I don't know when Chrysler switched to the silent type. Does anyone have any comments? 3. Camshaft Thrust Control my new camshaft comes with a spring loaded plunger that fits into a new special bolt that retains the camshaft timing chain sprocket. This plunger pushes against the inside of the timing chain cover, and controls end movement of the camshaft. The old engine from the 2000XJ lacks this feature, and obviously has some other way to control thrust. Does anyone know when and why they made the change?

If you are JUST replacing the balancer, and have NOT loosened the timing chain cover, the new balancer will fit on the existing seal and be concentric enough to seal correctly. People get into trouble when the loosen/remove the timing chain cover, and then the cover needs to be recentered on the balancer snout before it is tightened to the front of the engine.

That's the little devil in question. Mine doesn't have any of the locking features any longer, as some previous owner/repair person broke them off. I don't like trusting a critical connector like this when it only uses friction to be retained, and it's facing downward where gravity is working on it all the time. I will secure one of those Custom Connectors. You are a hero. Out of curiosity, HOW did you know that was a APEX? I sort of searched around on the web, and didn't find that result. (And I worked in the electronics industry as an engineer for 40 years, but not automotive stuff, so I have "some" knowledge of connectors.)

That is the primary failure mode for a harmonic balancer. Fix it soon, or else the outer ring can "walk" rearward on the hub and begin chewing up the timing chain cover.

I am looking for the connector on the body half of the wiring harness for a 1996 or later XJ (my engine in my MJ is from a 2000 XJ, along with the wiring.) Does anyone have a line on one in good working order? (Wells Automotive makes a replacement, but it's FIFTY DOLLARS, and that's kinda steep for a silly connector.)

The engine builder who is making my new short block tells me that Pete (known here as "Cruiser54") has passed away. He will be missed for his insight into old MJ's and XJ's. I hope his "Cruisers Tips" is archived for posterity here. EDIT: address for if anyone would like to send a card to his widow. The Family of Peter Rushbrook 7255 N Spur Rd Prescott AZ 86305-8928 Funeral / Celebration of Life: - May 29 5pm, Upper Ramada @ Watson lake in Prescott, AZ

If worse comes to worse you can take the prop. valve out of the vehicle, disassemble it, and push the shuttle back into place from one end. (It might also be a good time to clean the whole valve to make sure any crud from within the valve assy.) Of course, this will require bleeding ALL the brakes, but that's not actually a bad thing, especially if the fluid is old.

It really should not take much force. I use a small pick and kind of try to drag the shuttle back to the center. It should also have an angled surface on it that actuates the switch plunger, and that surface is easier to use to actually push the shuttle along. (That angled surface might be out of view through the switch port, but some slight coaxing might make the edge of the surface show up in the switch hole. Once that surface is visible, it's easy to push it along the rest of the way towards center.)