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5.7 drinking oil :/

4014 Views 20 Replies 6 Participants Last post by  tpm17
Ive got a 107,XXX mileage WK but the motor was rebuilt and has almost 50k on it. It has an intake/headers/exhaust and a mild tune with EGR blocked off. I also dont really beat on it.

This thing is eating 3-4 quarts of oil between changes and I notice once in awhile a small puff of blue smoke out the back when accelerating from a stop.

Ive had cars where the motor was going bad and they always showed signs or sounds of distress but this one runs and sounds like it does as always. I dont even have a "HEMI Tick". My driveway has no stains either.

Could it be a bad PCV possibly? Ive heard of them causing the loss of 1 quart every 500 miles in some cases.
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I would certainly check the PCV valve as a start.

Just remove it and give it a shake. If it rattles, it is likely ok. They are also cheap to replace, so you can always swap it out as preventative and see if that solves the issue.
A bad PCV creates excess pressure in the crankcase which can blow seals, then causing oil consumption. Replacing the PCV now though will be too late, if that is the cause of the problem since that much oil loss is huge. I've never had to even top off mine between oil changes of 7500 miles. Question, why was the 5.7 rebuilt with such low mileage on it ?
Question, why was the 5.7 rebuilt with such low mileage on it ?

Dumb ass brother hydrolocked it in d/t Charleston, SC while I was on deployment in 2010.
Ill have to order a PCV, NO ONE effing has one in town. WHY?! the 5.7 is practically in every chryco ever made this side of the millenia.

Ill have a compression test done later as well. If anything I hope I can get by with it for at least another 6 months and baby it. Im not throwing any more god damn money into this thing. Its nailed me $10k in misc b/s repairs in the last year and a half... well, some major but still.
While I agree with dmsfun that a stuck PCV valve could eventually cause motor damage, I don't think the amount of oil you are burning through necessarily indicates your seals are blown. In my experience, when a PCV valve is stuck wide open like that you'll also have issues at idle (which you do not report).

I think a couple of quarts in a few thousand miles could be just the valve staying open itself.
In fact, it does stall once in every couple of weeks at idle. Havent checked it yet. I forogt this weekend to do it.
I'll be ordering a new PCV on Friday. I added a slightly different Mobil 1 called "Advanced Formula" ... Whatever that is. It was all they had. Haven't noticed much oil burning since.

Curious; could I theoretically add heavier weight oil if I disable MDS with my diablo sport tuner?
Eh, just talked to a friend about it. He mentioned that it wouldnt work as it would f*** up the hydrualic lifters and MDS has nothing to do with it. He also said "American lifters designed only to work with 5-30 is the dumbest f***ing thing ever."

I installed the new PCV this weekend. I had to use channel locks to twist it out of position to remove it. Fair warning; you might need some needle nose pliers. The head snapped off its shaft when I tried to pull it out :( . Fortunately I had a tall friend with freaky long skinny arms who had the positional fulcrum to somehow pull it out. I lubed the new one and popped it in easily.

I noticed the old one was really oily and had residue. Cant tell if it was jammed as it broke when pulling it out although the small piston seemed to move freely. Well see from here. Im just about out of options with this oil burning issues (burned through a quart in 4 weeks) other than switching to straight up dyno oil (non-synthetic)

Install tip: Make sure the little hole under the head of the top of the PCV faces the breathing tube that goes into the head of the motor once installed
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A couple things. Why don't you have a catch can on that thing yet? That would for sure tell you if it's coming from the PCV System. You'd probably be emptying it every other day. Secondly, I install my valves just the opposite of what you're saying. The way you have yours installed provides a direct path from the valve hole, through the hose and into the intake. I install mine with the valve hole to the rear, away from the hose. This makes it a little more difficult for any oil to get around the corner and into the hose. Don't know if it makes a difference though. I've also looked in the FSM and it doesn't specify, so I guess they don't care, or it doesn't make any difference. Also, I've added a second in-line PCV Valve, between the stock one and the catch can, and it doesn't really seem to make much difference in the amount of stuff I get in the can. Just another experiment I tried to see if I could retard the amount of oil coming through the system.
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Im assuming the reason I would need a catch can is because too much oil is getting by the PCV and dumping it into the intake? And Im also assuming the PCV on backwards prevents more oil from getting by? Just wondering, you dont think that might have any long term effects? Im not a mechanical expert.
You would think haveing the PCV backwards would block all flow though...
LOL, remmy! I don't really think there is a "backwards", as there is a big open space at the top where the hole is and that oil will find its way around and into the intake, no matter which way it is installed. I've run them this way on both my Hemi vehicles, the LX for going on 8 years and never had a problem. Like I say though, I was just trying to slow the flow up a little. From what others say, I get about as much in the can as everyone else does. One other thing, you should be able to get that valve almost anywhere. I went through the same thing, and no one had a listing for either my LX or the WK. It is listed under under 04-05 Dodge Ram Pickup with the Hemi. Go figure!! The Napa part no. (Echlin) is, 2-9516. Good luck, and hope you resolve the issue.
Haha. Thanks. Ill have to try reversing it, saw another little puff of blue smoke today :(.
Blue smoke = engine oil is leaking directly into the combustion chamber, and pcv blowthrough would not cause this. My guess is either valve stem seals or piston rings were not done /installed properly by the rebuilder. I'd confront the rebuilder about the problem.
Blue smoke = engine oil is leaking directly into the combustion chamber, and pcv blowthrough would not cause this. My guess is either valve stem seals or piston rings were not done /installed properly by the rebuilder. I'd confront the rebuilder about the problem.

DUDE. I LOVE YOU. So glad you convinced me to check up on the warranty.

Jeep Since New: 108,927
Engine Repaired: 75,712
Current Engine Miles: 33,215

Date Repaired: Oct 09 2010

Warranty (even if it was a short block repair): 3 Year/100k

Looks like Im still under warranty :thumbsup:

Waiting for the dealer to call back once he pulls my hard copies up.
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I need to resurrect this thread. I bought a 2005 GC with a hemi. I got it fairly cheap cuz it had a knock that my mechanic thought was a rod bearing. Turns out it was a valve seat that had dropped and took out a piston. Took head to a machine shop and did just the seat that dropped and put in a new piston. Buttoned the engine up, started, ran, shut it down restarted BANG another valve seat dropped, another piston ruined. This time both heads go to machine shop, all intake valves seats replaced and another new piston. I'm into this engine almost 3 grand. It has 148,000 miles. Now my problem this thing drinks oil almost 2 gals. in 800miles. I put in a new PCV it still billows blue smoke. I unhooked the hose that goes from the PCV to the intake plenum and plugged the vacuum still blows blue smoke. I thought maybe the crankcase was being pressurized by blowby so I took the oil fill cap off and have been running it directly into the air. What do you think might be the issue?
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Asssuming they put the new pistons/rings in correctly, it sounds like there may have been more damage to the engine than you (and your mechanic) initially thought. Dropped valve seats are caused by excessive heat, and in many cases the stock temperatures these things run at are too hot. The cooling fan doesn't come on "high" until about 235-240* with the stock thermostat and PCM fan "start" temperatures are all set too low, IMO. Unless you find something simple amiss, you'll be taking it apart again.

I have two Hemi's in the range of the potential dropped seat problem. I've been very proactive though, beginning with cooler (190*) thermostats and fan start temps. set to 198 for low, 203 for medium, and 207 for high. Neither of mine never get more than about 212* and then just momentarily until the fan cools it back down. I recently did a test at a road construction site. We sat there for a full half hour in 104* temps. with the A/C on and it never got above 208 while sitting there. Once we got going it briefly got up to 214* and then cooled back down under 200*. I've been running this setup on both for about 7-8 years without issue.

Also, since the valve seat issue was starting to show up more again I decided last year, since we travel a lot, to pull both apart and have ALL the seats replaced on both engines just for a little added insurance. While I was at it I had them ported/polished and milled .030 in. When the guy was cutting the seats out of the heads off our LX (the one we use most for travelling), he was able to only cut them half way before they started spinning in the heads. They were probably candidates for the dropped seats. Glad I had it done before we had a problem.....perhaps in the middle of no where.

Good luck and I hope you find something simple otherwise, if the rest of the vehicle is sound, I'd be saving for a stroker motor, as the cost isn't that much more than a new 5.7 short block. You'll already have the heads done.
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My mechanic found the problem when they put the intake on they rolled one of the o-rings. No more blue smoke and the leak in gone.
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