Cherokee Chief Issues

[NorthMN]

Presently my daily driver is a 1980 Jeep Cherokee Chief (4wd, AMV V8). This Jeep has been in my family since it was bought brand new and sat in my grandparents garage since early 2000’s. A replacement motor was installed as well as a full rebuild was conducted in 2000. Ever since then it has sat in a garage until I drive it down to North Carolina and started using it as my daily driver. In doing this several issues have come to light that I’m hoping some of you could help me out with.

1) After getting most of the under carriage seals replaced I seem to have an exhaust leak that I need to chase. I’m debating just installing headers, but at the same time after reading a previous forum on here I’m leaning back towards new manifolds. Any advice on replacing the rusted out manifolds? I’m not a mechanic but have a general knowledge.

2) whenever I let of the gas going highway speeds I get what seems like back pressure. I’m assuming this is due to the exhaust leak since the motor mounts are fine. Any suggestions on what this could be? Since the exhaust has a leak my mechanic turned down the richness of the carburetor to eliminate a hot idle and this noise has been amplified since then.

3) Ever since I’ve taken this Jeep the A/C doesn’t work. I’m assuming that I’m going to have to replace the A/C clutch and compressor. Seems like the best I can find for a replacement is on Summit racing. Any tips on replacing the A/C clutch and compressor?

4) When driving the Jeep it seems like it’s having a hard time shifting from 2nd to 3rd. More so it tends to go from 2nd to 3rd immediately after shifting into 2nd. At this point I’m assuming a transmission rebuild might be looming. Transmission filter, seals, and fluid just changed. It will short shift for a while and then correct itself, then revert right back. Any advice?

5) earlier in the week I pulled on the spark plugs out to make sure they were still good. Upon putting it back in I’m now having an issue with the spark plug wire not fitting fully over the plug. Earlier today I was driving and heard a noise coming from the engine and started having mechanical issues (thought my transmission was about to go). Upon getting back home I realized the same spark plug wire came off. After reading some forums it seems like I can take a pair of pliers and bend the wire cap to make it tight again. Is this a good fix or should I just budget for doing a spark plug wire replacement for all?

Thank you for any advice, I’m a little out of my element and mechanic bills are racking up and was hoping to try and fix it at least diagnose some of these issues myself.

[Stuka]

Welcome to the forum.

1: I would suggest staying with manifolds. But first you need to track down where the leak is. The manifolds may be perfectly fine.

2: I am not sure exactly what you mean by this. What is it that you experience? Is it a sound, or a feeling or something?

3: The most common cause to A/C not working is a lack of coolant. The compressor clutch is pretty easy to check by having somebody turn it on and off while you look/listen to the pulley. If its just coolant, it may have to be converted as finding R12 these days is pretty tough. Any competent A/C shop can handle this.

4: What you describe here can most likely be resolved with adjusting the kickdown linkage.

5: If the wires seem otherwise in good condition, if you use some needle nose pliers to make the end of the wire a bit tighter so it will have better conduct with the plug terminal.

[NorthMN]

Stuka thank you for this I really appreciate it!

1) I’m going to use a shop vac and force air back into the exhaust and use soapy water to see where the leak is. I’m leaning towards taking the manifold off (if it’s not the cause) and giving it a paint job since it looks pretty rough and the Mn road salt didn’t do it any favors. Barring that it’s not the manifold then I’ll patch the exhaust with putty and hopefully be able to call it a day.

2) when I let off the gas it sounds almost like engine breaking in a manual.It’s a thudding noise but not anything that causes me to think the engine is about to fail. This noise was amplified when my mechanic toned down the carburetor to adjust for the exhaust leak. This noise is more so intimidating since it definitely doesn’t sound right, but it’s not a grinding or anything that causes me to believe I shouldn’t drive it.

3) From my understanding and some other forums on here this A/C compressor is a closed system and can’t be recharged. I guess it was my understanding that the whole system would need to be replaced since it can’t be recharged since it uses R12, but I’ll see if a local shop would be able to recharge it. I’ll have a buddy turn the A/C on and off and see if I can hear the pulley engage. If so you just saved me $130!

4) Not going to liethis one I’m not to comfortable with doing and will let my mechanic know, Thanks!

5) Yeah the wires seem to good and it’s just loose. I’ll adjust it tomorrow before I head to work.

Thanks again Stuka!

[SJTD]

Regarding item 2, what do you mean by getting back pressure? The vehicle should slow down do to "compression braking". Normal with a gas engine. An exhaust leak would have no effect on this.

Don't assume anything on the A/C. Get it checked by an honest competent mechanic. Might have a leak. Compressor won't run with no Freon in the system. Problem is that R12 is expensive and A/C work isn't cheap.

Converting it properly to R134a is also expensive. Need to flush it to remove the old oil and refill with the proper oil compatible with 134. Should change the 40 year old hoses too. Old hoses would work but they might be the leak. Would be best to change to a new style compressor also. Especially if yours is dead.

[NorthMN]

SJTD thank you for the reply I really appreciate it!

It sounds like a loud and deep wind noise, almost like what a a manual sounds like when engine breaking.

As for the A/C I will take it to my mechanic and see what it would take to convert it to R134a.

Thank you again I really appreciate it!

[Stuka]

I notice you posted this question twice. I have merged the two topics so answers from both are now in this thread. There are other answers above.

[NorthMN]

Stuka Thank you for merging them I realized earlier that I posted it in the wrong section and didn’t know how to delete it.

Also for the weird exhaust noise I had a buddy who is more mechanically inclined ride with me and he thinks it’s engine backfire. But not so sever to where it pops. I’m going to look into replacing the exhaust, but will still find t leak and make sure the manifold isn’t leaking or cracked. Any exhaust recommendations?

[letank]

Welcome to the asylum.... as for exhaust leaks... as you mentioned the vacuum blowing thru the tail pipe is a good way... otherwise the hose method is even better: put a copper 1/4" pipe or bit of brake line connected to a rubber or plastic hose -the copper or metal will be walked on the exhaust, while the engine is idling, transmission in park, emergency brake set and wheel choked, the rubber or plastic against your ear... it is a very good way to detect faint leaks.

Major leaks are the flange of the manifold, the donut on the passenger side with the heater stove , which must of us have removed, basically the internal flapper is yanked out and the holes are welded shut.

As for AC, it is a bit of a challenge, R134 being a smaller gas running at a higher pressure, you really need to change all the hoses for barrier hoses, and use a different condenser, a better compressor... Older hoses because they have been bath by the previous oil of the R12, can sustain some use... But you really need to have a proper diagnostic done to check why the system is failing, lack of refrigerant, seized clutch... then vacuum test... Some have suggested that buying a brand new system from vintage air is the way to go... but some adjustments are needed... check these posts for more insight:

https://www.fsjnetwork.com/forum/viewto ... =11&t=6472

or

https://www.fsjnetwork.com/forum/viewtopic.php?t=20560

sonoraed is a vintage air installer, check his built:

https://www.fsjnetwork.com/forum/viewto ... &start=300

[Stuka]

Stuka Thank you for merging them I realized earlier that I posted it in the wrong section and didn’t know how to delete it.

Also for the weird exhaust noise I had a buddy who is more mechanically inclined ride with me and he thinks it’s engine backfire. But not so sever to where it pops. I’m going to look into replacing the exhaust, but will still find t leak and make sure the manifold isn’t leaking or cracked. Any exhaust recommendations?

When you let off the throttle it will get more lean, and can cause the pops. Or, you can be rich and a large enough exhaust leak to allow fresh air to be pulled in. That fresh air mixed with the hot exhaust will ignite the fuel casing pops.

So first thing to do is fix the exhaust leak, it may also fix the pops.

[NorthMN]

Let’s just Thank you so much I really appreciate it!

As I’m coming to learn with this Jeep what I assume is going to be a simple project will take all weekend.

I never thought about testing the exhaust that way! I’ll have to give it a shot this weekend when I try and chase the leak.

From what I can the flange near the manifold has a nice size gap so I’m assuming that’s where a major leak is coming from. If so I’m going to try and order a new gasket and bolts... just have to find somewhere to order them from. The bolts are severely rusted and PB blaster heat will only go so far, so I’m just expecting them to snap and need to be replaced. If you have any suggestions on where to find the bolts that’s oils be greatly appreciated!

As usual I don’t know what I was thinking when I thought this would be as simple as replacing the A/C compressor and clutch and calling it a day. The fan runs great so I just assumed the lines would be fine. To my knowledge it still has the original compressor and clutch so that’s why I was assuming they both needed to be replaced. Especially since it sat in a garage for a decade without being ran.As more and more people on here explain the A/C common issues it seems like the best thing is to take it to my mechanic and just have replace the whole system. As a short term fix since it’s getting hot here in North Carolina I might replace the clutch and compressor until I can afford to fully replace the system using R134. Thanks for the references these are great starting points for when I convert.

Thanks again for your help I really appreciate it.

[NorthMN]

Stuka that makes sense, I’ll chase the leak this weekend. After looking at the exhaust flange it looks like it has a nice sized gap so I’m assuming that’s one of my leaks. I’ll chase the entire exhaust just to make sure.

I saw that Summit racing offers the replacement gaskets, but do you know where I could get replacement bolts for if I have to replace the flange gasket? They’re severely rusted and I have a feeling they’re going to snap off during replacement.

[tgreese]

Mechanic's stethoscopes are not very expensive - https://www.harborfreight.com/mechanics ... 63691.html

Be careful not to shoot hot exhaust gas into your ear with a random piece of rubber hose.

[tgreese]

Stuka that makes sense, I’ll chase the leak this weekend. After looking at the exhaust flange it looks like it has a nice sized gap so I’m assuming that’s one of my leaks. I’ll chase the entire exhaust just to make sure.

I saw that Summit racing offers the replacement gaskets, but do you know where I could get replacement bolts for if I have to replace the flange gasket? They’re severely rusted and I have a feeling they’re going to snap off during replacement.

The mechanics (now technicians) at the Jeep dealer would take the Jeep on the local highway for a high-speed run before removing exhaust manifolds. This would make the bolts and manifolds rocket-hot, and they would come out. Danger of a severe burn was high, but that's what the pros do. Use mechanic's gloves and sleeve protectors. This topic has been covered a lot in old posts - it would be worth your time to do some research and get as much advice from old posts as possible.

I would get new bolts from the local hardware store. Better to not break them and reuse, if you can.

These Jeep did not use any gasket between the heads and the exhaust manifolds. Iron on iron. Conventional gaskets will blow out eventually, and the no-gasket seal works. Same between the exhaust pipe and manifolds.

[NorthMN]

Tgrees I really appreciate it!

I’ll stop by harbor freight this week and pick a mechanics stethoscope.

That’s an interesting technique, but makes sense to help loosen up the manifolds. I’ll make sure to look back and see what others have said. I’ve browsed a few when I was thinking about getting headers and after reading the forum I’m glad I didn’t.

I’ll see if fastenal has any in store and pick 2 up. Was just curious if anyone knew the size of them so I could just order them and have it on hand since this is my only vehicle. I’m glad you said it doesn’t have a gasket between the heads and manifold. I’m sure I’ll be spending some time finding the leak, but I’m just assuming it’s coming from where the headers meet the manifold.

Thanks again I really appreciate!