Hey guys. I have a 98 Jeep grand Cherokee with the 5.9 engine, I fixed my plenum about 2 months or so ago.. I used a ebay aluminum pan and a new felpro gasket and torqued all the bolts according to the TSB and I used a new felpro intake manifold gasket and new bolts and torqued them down correctly as well..

I also installed a PCV catch can... and I replaced my valve cover gasket's and got a new 02 sensor.. I checked my oil level like a month ago and I noticed it was below where I remember filling it but I checked it an hour or so after I last ran the engine and I ran it cold for only a minute.. So people told me it was just because the oil was stuck on the top of the engine from being run cold like that and to wait overnight... So I did and I checked the oil level it was back where I remember it was.

Today I decided to check the oil level and it was a tad below the mid point on the ok line.. It was still well above the refill line tho but it was lower then when I last checked.. I ran the engine up to normal operating temps and checked the oil level 30 minutes later and it was right on the line where it says low... Basically I only had 1/4 of an inch of oil on the dipstick... To me this means im about a quart of oil low. It has been 3,000 miles exactly since I did this plenum fix and refilled my oil... And before this I was losing a quart of oil every 3,000 miles. Sooo it seems like im still burning oil.... But I am going to let it sit overnight and check the oil level one more time.. If it isn't back to where I filled it up last time then im deff losing oil..

Another thing is my engine is still pinging.. Not as bad as it used too, but then its summer time and it never pinged too bad in the summer.. the winter it did.. It doesn't ping on WOT, but It does ping if I get it in a sweet spot at around 2500-3000 rpm..

This is starting to really **** me off to tell you the truth.. Im about ready to set this engine on fire.. or blow it up... It only has 144,000 miles.. Oil pressure is always at 30-35psi when warmed up.. Compression is really good actually its a little too high most likely from carbon build up..

And my catch can seems to be catching a lot of oil.... Like After 1500,2000 miles using it, it was almost full and I believe its something like a 500-700ML container.. My rear main does leak, and it leaks worse since I switched to synthetic blend oil after the plenum fix but not enough to show any drip marks when I park... I also noticed oil seems to be leaking out of the breather hose grommet on the drivers side valve cover.. so I might have to seal that up with some RTV.. but I don't have any air blowing out of that.. I do have air going in tho.. so maybe its just oil splashing or something..

What should I do ?? I looked in the manifold and it is wet coverd on the walls and stuff but I think that's just from the pcv .. I don't see any oil pooling but its always hard to tell in the back..

I am deff not going to take this manifold off again, if it really is still burning oil and still burning it 3,000 miles a quart.. then it cant be my intake can it ? Specially after I fixed it... I don't think its a valve seal because I don't have oil fouled spark plugs.. I dunno im at my wits end, and im thinking of just living with it.. Filling it up when it needs it and if the pinging destroys the engine in the future whatever..

 

Sounds like the PCV is sticking - try cleaning it good with carb cleaner or install a new one. Also, did you SeaFoam the engine after installing the repaired plenum to get rid of the carbon deposits/oil build up in your combustion chambers/pistons/rings?

 

Seafoam sounds like a really good place to start.

 

I did seafoam, blue smoke was blowing out of the tailpipe when I used it after the plenum fix.. I haven't done it since... and the PCV is new from the dealership.. Its only like 6 months old. I can deff feal it wobbling around inside.. and if I kink the tubing it stops and it if I release it starts to wobble around really fast at idle again so it isn't stuck

 

Do the seafoam again. Sure can't hurt.

 

The problem when I use seafoam or mopar combustion cleaner... Is when I use it let say through the brake booster line and only half a bottle... once I turn my engine back on it CLANKS hard... like really loud.. like two pieces of steel smacking eachother... and if I drive it and I get above 1,000-1500 rpm.. The engine pings extremely horribly for a minute or so ... Enough for me to get scared and I shut the engine right off..

It always does this when I use seafoam.. I don't know why but I have used seafoam so many times since I have had this car.. It hasn't done anything besides make my engine sound terrible

 

does your truck stall when you pour the sea foam in the brake booster line?

 

You could always pull your heads off and see what's going on in there.

 

In my experience, the oil loss was attributed to the Fram PCV valve I threw on. Went back to Mopar PCV and it definitely helped. Next is to put thicker oil in. With that many miles, you should be up to 10w40 at least. I started using thicker oil around 65k and it also helped usage.

That aside, engines do use oil. Some more than others. I burn 1 qt every oil change which is about 4-5 months and 3k or so. It is my daily driver so it starts and stops a lot which will burn oil. On a road trip, it barely uses any. If it were me, I would:

1) run another can of Seafoam through booster hose
2) Install one step cooler plugs (or at least ones with shorter nose as they retain less heat)
3) Install 180 stat
4) Change upstream O2 to a new NTK part
5) Run Techron treatment every oil change
6) Put in Valvoline Maxlife 10w40 oil.

 

How is Seafoam going to fix a oil consumption problem guys? Seafoam is not a endall fixall. He has excessive pcv oil blow by, rings, valves guilds or valve seals. Yes all motors use/burn/consume oil its a given fact, my motor does not leak a drop my motor is tight and my motor burns/consume a 1/4 liter every 5000 miles.