I use this on OBD-1:

 

Oh cool, they made a how-to video

 

Air Conditioning question!

Had my AC compressor seize and I had a new one placed in an emergency as I was out of town and had to head back into town for work the following day. The shop that placed the new compressor made my jeep drivable but not AC-able. Curious as to if I can fix my system with the suggestions made by the shop as listed below, or if I'm in over my head. The new compressor was put in about 5 months ago and I've had zero problems since.



Any advice is much appreciated! its 105 degrees here!


2000 sport 4.0L

 

Anybody ever separate the third eye in a '97 up XJ? Wondering how the red lens is attached to the gray housing. Figured I would ask before I broke it.

 

you mean the brake lights?

 

I'm sorry. Should have been more clear. Yes the brake light on the hatch.

 

Is it normal for the old head gasket to come off in a single piece and in amazing condition?

 

Actually they could have put in an AC delete pulley. But since you have the new compressor, here's what you'd basically need to do. Only you can decide whether you want to do it yourself or have a shop do the work. It's not rocket science, but you have to know a few things and have a few tools that are different than working on the other parts of your vehicle. (The major tools needed being an AC gauge set and a vacuum pump. You can actually make a pump out of an old room air conditioner or refrigerator compressor!) There are lots of instructional videos on youtube that can help with procedures.

When a compressor fails it typically sends metal shards into the system meaning you have to flush it out. Flushing kits that work with compressed air and flushing solvent are not expensive:

https://www.amazon.com/FJC-2710-Syst...c+flushing+kit

https://www.amazon.com/Four-Seasons-...WNBMXXXV2583T0

You'll also need a drier for the air from your shop compressor when using a kit like this. You don't want to be filling your AC system with moisture! The disposable desiccant type inline driers commonly used for painting will work. (The refrigerated or heated air drying systems used by pro shops cost big $$$$!)

http://www.northerntool.com/shop/too...9833_200319833

Unfortunately the parallel-flow condensers used in R134a systems cannot be reliably flushed out and should be replaced. The drier/accumulator and expansion valve will also need to be replaced.

There's a lot of discussion as to whether evaporators should be flushed or replaced. The issue is that it can be difficult to get all the flushing compound out. I've successfully done it but followed up the flush with dry compressed air for a while to make sure all the solvent is gone. (Really you should do this with all the flushed out parts.)

You don't flush compressor, drier, or expansion valve.

You'll need to add the amount and viscosity of PAG oil specified for the system just before buttoning it up. (The new compressor may have come with assembly oil which would have to be dumped out and replaced.) There will be a specification for how much the compressor is supposed to hold, the rest can be put into the drier. Oil should be put in just prior to closing up the system and pulling vacuum because it is extremely prone to absorbing atmospheric moisture. This moisture does not come out when you vacuum the system and will form acids with the refrigerant that eat small holes in metal parts such as the evaporator. Likewise the drier should be exposed to air for the minimum time possible.

I like to use Nylog sealer on the seals and fittings, makes it much less likely that there will be a leak.

https://www.amazon.com/Refrigeration...rds=nylog+blue

When you charge the system you may want to put some dye in for the purpose of tracing leaks. (Though if you're going to be doing your own AC work an electronic detector would be a good investment.)

NEVER put sealer into the system!! This stuff hardens on contact with the air and can really make a mess of things when the AC system is opened up for service later.

 

I know most folks here do their own work, one day I hope to join that crowd. For now, lack of a garage, space, and knowledge hold me back (working on the knowledge part though). Since I don't know how to weld and don't have the space for big projects, what is the best way to go about replacing a floor pan? Basically the driver side floor pan on my 99 cherokee is, well, gone. If ya get under the jeep and poke, there's no metal. I've gone over sticks that have happened to pop up in just the right spot and push my foot up. Great for comic relief, not so great for life of the jeep. I'm new to all this kind of stuff so I'm curious what kind of shop is the best to take it to, or really, who in general does those kinds of repairs? Also, is it better to order the part myself and then take it to someone to put in or is that even a thing? Last question, what would be a fair price range I could expect for something like this?

 

So it seems like under light power or no power it'll unlock but there's probably some binding and/or flex in the materials that with anything over minimal throttle it'll probably stay locked...

Beat my own dead horse to death

Edit: Still considering a rear lunchbox...can always upgrade and sell it right?:-P

 

Can someone describe the difference in sound between a piston slap, Rod knock, and lifter tick? Thanks.

 

I have stock differential voers on my 99 XJ. I have though about replacing them with aluminum covers..

But more importantly, I was was wondering why the stock covers require removal/scraping/acetone/RTV sealant..etc.

Are many people using the gaskets I've seen as an alternative to sealant and wouldn't it make more sense to have a cover that had a drain at the bottom and a fill cap at the top?

Sorry if this has already been answered.

 

You'll find examples of these all on youtube. A rod knock is going to be a heavy knock under load, you may even feel it. Lifter tick is a fast, light clicking sound. Piston slap is somewhere between these.

Rod knock is the worst - engine self-destruct is not far away when you hear it. You can go a long way with the others.

 

A few reasons I can think of. Cost is the most obvious one, single plug is cheap. RTV is also very reliable and cheap. There are some paper gaskets for these differentials out there, but generally require some product sprayed on, if not a small amount of RTV, and they require a flat sealing surface. You can peel a steel diff cover off, Hammer it mostly flat, and just seal it up again with RTV. (I've done this). Aside from cost, a drain plug is a vulnerability. Not good on an axle. Change interval isn't 3000 miles anyway. These things will fill up with little bits of metal sometimes and it's important to inspect your diff and clean it out properly.

They weren't designed for water fording.

 

Thanks, those are good points.

I kinda figured if the differential gaskets are so great, why isn't everyone using them and posting that they're the only way to go.

I come from a background in motorcycles and builds/mods there so a lot of this is new to me. I appreciate all the good advice I get here.