Oil issues

[CLNethery]

I drive a '99 TJ with 227,xxx miles on her. Recently (january) I noticed an increase in loss of oil, from nearly no loss to +/- 3qts a month. I'm not noticing any puddling underneath which says I must be burning it. My best guess, considering the mileage, is that it's that the piston rings are just worn out and can't hold a proper seal anymore. Because I am on my summer break, now is the best time for me to do an overhaul if need be. Questions: How much damage (to the jeep and my pocket book) will it cause if I just keep adding oil every time it needs it instead of actually fixing the problem? Can anyone say whether this is a problem that even needs an overhaul? Advice on diagnosis? Because it's my DD, I would rather not rip it apart and be without a vehicle for so long, but if it's the lesser of two evils - so be it.

Thanks guys

[Sharpe]

What engine? Buying a rebuildable core to work on while you continue to drive the jeep is a perfectly viable option. You can get an engine swap done in a weekend with some help.

[KrazyKarl02]

You can limp a fuel injected engine along for quite sometime with oil loss. You will start fouling plugs and smelling like a 2 cycle weedwacker, but it will go for quite a while as long as you keep topping it off.

As for the diagnosis, a quick simple thing is to pop your valve cover air breather off and see if it is constantly blowing air out of it, more than likely it's air and oil. A more in depth approach would be to run a compression check on all the cylinders. You can buy a compression checking gauge for pretty cheap or O'reilly's might even loan them out. It's no more technical than changing the spark plugs to do. With the compression gauge you screw it in your spark plug hole, crank the engine over, then read the pressure. You should be over 125 psi. You are also looking for deviations between the cylinders (like if cylinder 1 is 150, and cylinder 2 is 125, you have a problem). That's where I would start.

More than likely you are correct in your ring assumption with that many miles on the engine. You then have a few options depending on your pocket book, level of skill, and free time:

1) You could pull the engine, remove the crank, pull the pistons and just put new rings in it. This is going to make the problem go away for about 10,000 miles and probably cost the least
2) You could look for a crate engine from Jeep, I would imagine this would be in the $3000 range, then just pull your original engine, install the new one and swap the accessories. If you did this you would be out $3000, but your downtime could probably be a weekend or less.
3) You could pull your engine, send it to a mcahine shop, have them rebuild it, and re-install. I would guess a decent rebuild would be ~$1500, the problem is the machine shop would probably have the engine for ~2 weeks, so while it's half the cost of the crate motor, it's a lot more downtime.
4) Like Sharpe said, find a rebuildable core, have the machine shop rebuild it, then just swap it over a weekend.
5) Another viable option is to check junk yards and see if they have one pulled from a wrecked car, it is a gamble, but if you're on a college student budget it might be worth taking. Sometimes they will tell you the miles the vehicle had before the engine was yanked so you can get a feel for the engine condition.

Everything I listed is there is just my pulled out of the air estimate on what that stuff could cost, so it could be more or it coukld be less. Another expense in repairs like this is all the other stuff on the motor, like a water pump, engine mounts, spark plug wires, etc.... Are you going to pull the engine out and then put a water pump with 200k miles on it? I wouldn't but you could to save cost.

[uglyota]

Orrrr....you could do a 5.3 swap!
Can't you even do a ring and hone job with the motor in place? Pull head and pan, replace rings and bearings, slap it back together with new head bolts and head gasket? That would probably be the middle ground between a junkyard motor and a full rebuild

[Seth]

What motor? How many miles are you driving to burn 3 quarts?

[sam_hodnett]

My high school truck burned a quart a week. I drove it like that for 3 years and my brother drove it for 2 years before it finally gave out. But it was getting about 2,000 miles a month put on it.

[CLNethery]

I'm running an 4.0L inline 6, 5 spd manual transmission. I burn a quart of oil every 250- 300 miles. Thanks for the input, my dad is in Canada on business this week so we're going to look at all the options when he gets back. 5.3 swap would be sick, but I'm a broke college kid so not really an option at this point. Considering the miles, I don't think I can sell it for what I would want. Which means I might as well do a fix that is a balance of long lasting but not necessarily as extensive or expensive as doing a 5.3 swap.

[tommy53002]

So it's consuming 3 quarts every 300 miles? That is a lot. I don't know how long that could limp along.
Swap in a rebuilt long block and be done with it for another 200k...

[CLNethery]

No, I added 3 quarts in the last 740 miles.

[CheapJeep]

Karl pretty much covered everything as far as rebuild options go. If you're attached to your rig and plan on building it over time, an LS swap might be a good choice... $750~ 5.3 with accessories and ecm is pretty standard going rate at yards.

You might try a quart of this with your next oil change while you're limping it along. http://lucasoil.com/products/engine-oil-additives/lucas-heavy-duty-oil-stabilizer (I use it in all of my vehicles and race cars, it works...)

[Fredo]

Robbie brings up a good point. The snake oil challenge is worth a try.

Lucas is some good stuff. I've got a engine that wouldn't probably be alive without the stuff. Refer to this thread to see what I'm talking about: http://www.tamor.org/forums/showthread.php?6389-Gentleman-Place-Your-Bets!!!

[CLNethery]

Thanks for the info on the additive, I'll pick some up next time I'm out. A little back story, I forgot to mention but remembered after reading Fredo's old thread. About 6 months ago my oil pressure started dropping off to 0 then bouncing back as I drive or keep the rpm up. Not sure if that helps diagnose the issue or not, I considered replacing the oil pump but never got around to it. Newb question here, when you say "LS swap" are you referring to the 5.3 and 'LS' is just a style? I'll start checking the salvage yards around to see if I can find one for decent price. It's my first rig, so it's hard to decide whether to keep putting money in just to fix it, or while I'm fixing it and spending the money (money is tight) I might as well upgrade. If I'm not upgrading it almost makes more sense to sell the thing since it's bound to break again. If I can find a solid 5.3 and can convince my dad, I agree that's the way to go (looking at the big picture). I appreciate all of the help guys.

[sam_hodnett]

I agree an LS swap would be slick, but if you think it has adequate power for what you are using it for right now, just swap in a rebuilt block until you are done with school and can afford to do a nice 5.3 swap.

[colman]

jump on cl and find someone parting out a jeep and get the motor and swap it in. cheapest option in the long run if you plan on keeping the jeep for more than a few months

[KrazyKarl02]

I agree an LS swap would be slick, but if you think it has adequate power for what you are using it for right now, just swap in a rebuilt block until you are done with school and can afford to do a nice 5.3 swap.

While he's doing the LS swap he should go ahead and do the one ton axle swap....

[BroncoJo]

While he's doing the LS swap he should go ahead and do the one ton axle swap....

Only if he plans on keeping it for a while...

[eight]

Why would new rings last only 10,000 miles? Inframe overhaul can be done over a weekend easy. Really isn't that much to it. Problem is you don't know what you're dealing with until it's opened up as far as condition of cylinders, pistons, and crank. Crank is usually good unless it's knocking or loss of oil pressure, so you've got a questionable there already. If you check compression and all are low but even the cylinders are probably fine. If one is near zero that's likely broken ring/piston which would mess up the cylinder wall. Also the chance it could just be bad valve stem seals.

Replacement used engine is probably your best bet. I usually came out ahead after parting out the old engine.

[KrazyKarl02]

I was assuming with that many miles the cylinder walls would no longer be in good shape.

[CLNethery]

Alright, so I got around to doing a compression test this afternoon and found that all cylinders are below spec for pressure. Spec is 120, mine ranged from 100 -115; majority hitting the 105-110 mark. With an engine that has close to 227k miles on it, I'm not real surprised that they aren't at that factory mark. Since I couldn't single out a cylinder, I'm pretty much still at square one. Next thing I plan on doing is changing oil and dropping the oil pan while I'm at it to see if there is anything there to see (just curious after reading Freds thread from a while back). I've been using Mobile 1 High Mileage synthetic 10W-30, but because it's not cheap and for now I have to keep adding oil on a regular basis; are there any recommendations for a cheaper oil?

[CheapJeep]

About 6 months ago my oil pressure started dropping off to 0 then bouncing back as I drive or keep the rpm up. Not sure if that helps diagnose the issue or not, I considered replacing the oil pump but never got around to it.


Next thing I plan on doing is changing oil and dropping the oil pan while I'm at it to see if there is anything there to see (just curious after reading Freds thread from a while back). I've been using Mobile 1 High Mileage synthetic 10W-30, but because it's not cheap and for now I have to keep adding oil on a regular basis; are there any recommendations for a cheaper oil?

If you were losing/had no oil pressure and kept driving, best case is your oil pressure sending unit is intermittent, worst case your oil pump is failing and likely trashed the rod and main bearings. Not likely you're going to see much by just dropping the oil pan other than potential glitter/bearing shavings in the oil. I would pull a couple rod and main caps to check the bearings.

[KrazyKarl02]

I'm sure someone will disagree with me, but synthetic will seep thru worn out rings more than conventional motor oil. I would go back to normal motor oil, that will reduce some of your consumption. Other than that, it's either new engine or rebuild time.

Well or it's buy oil by the case time....

[mudtoy67]

Well or it's buy oil by the case time....

As a member of the oil industry I approve this method. :D

[Sharpe]

You could put your roommate's used oil in your truck daily like Ryno did with the Exxon Valdez.

[uglyota]

Even compression sounds like good news to me, no one cylinder wall is trashed, rings are just worn. Spend a weekend putting new rings and bearings in it and call it good

[eight]

If you pull the pan, clean the screen on the oil pump.

Is there anything proven of "high mileage" oil? I always just figure thats marketing bs.

[DRAGOONRANCH]

Buy your bargain basement oil from Napa (or whatever parts store), no need in spending dough on synthetic or the like now. You can go to Mustang Cat and get an oil sample kit from them to see what all is in the oil, that's what I use on my truck and equipment to keep an eye out for problems. Part # 1612, I have the little siphon pump that will pull it out of the dipstick tube if you want to pull a sample before you drop the pan/change oil. The tube doesn't fit down the dipstick tube on my wife's explorer, so that might be an issue.

[KrazyKarl02]

Buy your bargain basement oil from Napa (or whatever parts store), no need in spending dough on synthetic or the like now. You can go to Mustang Cat and get an oil sample kit from them to see what all is in the oil, that's what I use on my truck and equipment to keep an eye out for problems. Part # 1612, I have the little siphon pump that will pull it out of the dipstick tube if you want to pull a sample before you drop the pan/change oil. The tube doesn't fit down the dipstick tube on my wife's explorer, so that might be an issue.

Did the sample from the red truck come back with "crank is about to break in half"

[DRAGOONRANCH]

No, but the red truck is the reason I take samples every 12,500 miles (change the oil every 25k) now. I was using the Amsoil sample kits, but found the Caterpillar ones get read faster and are a bit cheaper. Besides, I buy them by the dozen for work anyways.

[CLNethery]

Haven't updated in a while. So I replaced the bearings AND the oil pump, all were original so they had 233k miles on them. That fixed the oil pressure issue, but not the issue with it burning oil. Long story short, pulled the engine over the break to find 3 cracked pistons a cracked exhaust manifold (obviously not part of the problem, just a different problem), and one worn out engine. A month later, it's still sitting at the machine shop getting worked on.
Work on engine completed or in progress:

Overhaul
- grinding crank and connecting rod journals .010"
- boring cylinders .030"
- replacing pistons
- replacing camshaft & lifters

Cleaned & checked head - no issues
Cleaned & checked block - no issues
Checked timing gears and chain - no issues
Replacing freeze plugs
Replacing exhaust manifold
Resurfacing clutch

[tommy53002]

That ought to freshin it up.

So they aren't doing any head work? Seems like, after 233K, a valve job and resurfacing the head would be a good choice.

[BroncoJo]

Shouldn't you replace the timing chain and gears as well?

[KrazyKarl02]

Shouldn't you replace the jeep?

Travis, I fixed what you said for what you should have said.

[tommy53002]

Shouldn't you replace the timing chain and gears as well?

Yes. Time set is a wear part. Plus it's cheap and easy to do at this point.

[BroncoJo]

Yes. Jeep is a wear part. Plus it's cheap and easy to do at this point.

Tommy, I think you meant this...

[CLNethery]

Valves are in good shape, so we left them alone. We did end up replacing the timing chain though. Spent the weekend getting it re-installed, unfortunately we spent a majority of the afternoon Saturday wrestling the transmission. Looking back now, a transmission jack would have been a wise investment. Anyways, planning on finishing up the job this coming weekend with just a few minor things being left to do.