When to just replace parts more of a discussion then question

JeepingNet

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Location
Saint John, NB, CA
This post is as much for me to document for myself what I'm doing to get some feedback as it is asking for help - More of a discussion.

I'm finally tackling the leaky valve cover. But while doing this job, I'm finding many questionable old original parts and wondering if, since the jeep is now 20 years old while I have things apart, I dump money at it. It would be easier to tackle this all at once, and it will all need to be replaced in the next five years.

The rear Main seal needs replacing as well. But the exhaust is all hacked together by a previous owner, and even it looks like it welded at the manifold. I've had CO2 sensor errors since getting the Jeep and have never been able to get them out. Exhaust manifolds themselves are looking a little chunky with rust. The valve cover leaked so much over the last year that the engine was just coated in oil down the backside, and there was oil all over the exhaust manifolds. Someone also, along the way, removed the rear cat.

It's a 2005 LJ Rubicon with 185,000 miles on it. The rockers and push rods looked great when I looked at them last night. I might have an exhaust leak somewhere around the manifolds, but it didn't run too long since the oil started to smoke like crazy on them. Cleaning the oil between the intake and manifold will be nearly impossible.

So here is my thought
1. Remove the drive side fender
2. Remove intake, exhaust manifold, remove full exhaust
3. Degrease like crazy
4. Take the time with the intake off to clean it all up
5. Do the rear main seal and oil pan seal
8. Install new exhaust manifolds
9. Install new cat system
10. New O2 Senors


Parts:
Rear Main Seal — FEL-PRO BS40183
Oil Pan Seal — FEL-PRO OS34308R
Exhaust Manifold Front — DORMAN 674467
Exhaust Manifold Rear — DORMAN 674468
Exhaust Manifold Hardware — FEL-PRO ES7511
Exhaust Gasket (I like Fel-Pro) — FEL-PRO MS93094
New Cat System. — DAVICO 19281 E.P.A. Compliant
O2 Sensiors — Have have already
Oil pump — MELLING M81A
Oil Pickup — MELLING 242S
Camshaft Sync — 53010624AC

Maybe
Water Pump??


It will be about $1500 CDN in parts, but I plan to keep this Jeep forever. The only reason I might not do it is I've been finding the aftermarket parts are sometimes garbage. But now does feel like the right time to do all this job. I think its my choice of exhaust manifold that cat system that concerns me. Any better recommendations?
 
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I put three Felpro rear main seals in my 97 before I gave up and used a Mopar. Leaked worse than the originals with the Felpros. Use lots of red Loctite and oil the lip.

I put a Meling regular volume/pressure oil pump and pickup on mine while I had the pan down the first time. Thoroughly cleaned the pan. Felpro oil pan seal.

I noted the size and condition of the rear crank bearing.

I could put a finger on the timing chain and it was sloppy so I pulled apart the front and did a Melling timing chain set and Napa/Gates water pump. Had a devil of a time getting the water neck to seal... replaced it and the new one wasn't much flatter. Took a lot of sanding and RTV. Discovered the fan clutch was shot and replaced the lower radiator hose and installed constant tension clamps.

-Mac
 
Hello, Saint John, NB! Spent a year there once on a big IT project. Summer and Spring are great. Glad to be back in TX for the winter.
I agree with a planned approach to maintenance, when possible. It is always cheaper and easier to perform maintenance in an orderly manner, in a shop, where parts / supplies are available. I travel down the Padre Island Nat'l Seashore in Summer and dread the thought of something serious breaking when I am a hundred miles from help. I just spent a fair chunk of change on my '06 LJR to replace the original fluids in everything, and have the front end restored from damage cause by the former owner flat-towing with the steering locked.
I think you might go a step further and anticipate what might go wrong on the trail and how to reduce your risk. For example, replace all of your hoses and fan belt before you go, but carry a spare fan belt with you, along with your basic tool set. I'm not familiar with the perils of rock crawling, but I would consider carrying an air supply and a tire patching kit. You should also carry a fire extinguisher and first aid kit. Being prepared should reduce anxiety caused by being remote, so you can enjoy yourself!
Good Luck!
 
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I'd do everything you have outlined, plus add in replacing the oil pump as you already have the pan off, then run it. I wouldn't do the water pump by itself unless you are having problems with it or cooling system. Generally when replacing the water pump you should also check the timing chain, fan clutch, pulleys and belt and replace as needed at the same time. Rad and hoses as well. You said you have the O2 sensors already, they need to be Mopar or NTK, any other brands are unlikely to yield positive results.
 
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Perfect, thanks, everyone, for the suggestion so far — I've updated my original post to include the oil pump and pickup valve and I'll do the OPDA since I had no idea when it was done (if ever).

The O2 sensors I have are NTK — and I did just replace the belt and tension thingy because I had just replaced the alternator that locked up, and the tension pully was actually cracked.

Dr. Internet, yeah, it is -20 here today, but I'm lucky because one of the things I did while taking the last year off Jeeping was insulating my garage with r38 in the walls and r60 in the ceiling. It is kept at 70F year-round now so I looking forward to working on the Jeep now.
 
At 185k, unless done recently, I'd be replacing all the fluids and the following:

Entire cooling system, including radiator and fan clutch
Timing chain and associated parts
RMS and oil pump
Valve cover gasket and grommets
Along with the O2 sensors you mentioned.

I'd also disassemble and inspect the brakes, and check the steering. A ZJ upgrade, using Moog parts, is an inexpensive way to do the latter.
 
Philosophically, I'll replace old but still functioning parts if I already have it apart for something else and if the cost of a new part is low enough that it's worth not having to repeat the disassembly process in the near future.

I don't have a strict formula for this, it's just a gut call on a case by case basis. Some examples are...if I drained the cooling system to do a water pump or a radiator or to do a flush, I'm going to replace the thermostat. If a driveshaft is out and I don't know how old the u joints are, or I have the knuckles off and dont know how old the ball joints are, they'll get replaced.

If I'm messing with the exhaust and it's not much more effort to change some old O2s, I'd probably do it.

I don't take things apart just replace a part that isn't broken.