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big wad of milkshake oil on air filter and front pcv, oil is fine

streetpirate

streetpirate

NAXJA Forum User
Location
Oregon City, OR
'87 renix 4.0

noticed a definite loss of torque, and a 2mpg drop sometime before my last oil change, oil looked good and black when I changed it last (4k ago ish)

the front valve cover pcv hose that goes to the airbox is almost clogged with thick coagulated water/oil milkshake, but all clean under the valvecover

my dipstick was getting surface corrosion on it and the very tip would have a drop of milkshake oil on the tip, but the rest of the oil looks fine.

pulled the head, gasket looks good. no visible cracks.

header tubes 5 & 6 were completely broken off the rest of the header

all the oil I drained is good and black, the coolant I drained looks great, but the coolant that drained out of the head after I had it off was oily and silty?

wtf? pics of gross jeep splooge

DSCF0030.jpg

DSCF0028.jpg
DSCF0029.jpg
 
I'm starting to get these same symptoms at 209k... subscribed. I have the mileage drop (though I've fixed MOST of it with a new O2 sensor, I was 5-6mpg down) and the dipstick corrosion, add a tiny bit of milkshake in the oil cap and also it drinks oil like it's going out of style. I put about 3 quarts of oil into it every two weeks or so. It doesn't seem to be burning it, and it leaks so much transmission fluid I can't really tell if it's leaking oil too...

EDIT: 91 HO 4.0 here, though. Slight noticeable power reduction, or my butt dyno might be miscalibrated.
 
There is a potential clue in the pictures.. you know how your air filter is always sagging down into the airbox? The retention rails on the lower airbox are pooched out about 1/2 inch per side. How much dirt is in the air inlet tube to the TB? Compression test results?
 
My airbox on my 89 4.0 is pooched out the same way on the bottom. Any ideas on a cheap fix, other than outright replacement?
 
JJacobs said:
There is a potential clue in the pictures.. you know how your air filter is always sagging down into the airbox? The retention rails on the lower airbox are pooched out about 1/2 inch per side. How much dirt is in the air inlet tube to the TB? Compression test results?
Click to expand...

I was going to do a compression test but I was set on removing the head
in a hurry, i know, it was a mistake not doing the test.

cylinder walls look amazing for 275k, with one cylinder that has a fingernail catching ridge.

yes, the airbox is pooched, and yes, my intake ports have some crud build up, but the combustion chamber has no build up


could it be that the pcv tube was already kinda clogged with oily crap and then it had a leak and sucked in some water? the pcv tube where it connects to the valve cover was clean, and didnt look like it ever even had milkshake on it while the rest of the tube was clogged and the rest of the moisture in the system was from a leak in the pcv tube?
 
Streetpirate:

How do you use your XJ? Lots of cold starts and short trips? If the engine does not get to normal operating temperature the moisture in the crankcase does not get burned off.

The rusty dipstick and the small milky-mix could be related to simple condensation in the crankcase and a clogged or poor CCV system.

I would service the CCV, making sure that all orifices and tubes are clear.

How many miles do you put on in 90 days? If less than 3k, then you should consider changing the oil every 3 months to get rid of the contamination. I would also consider a change to a diesel motor oil, Shell Rotella is my favorite. You can buy the 10w30 dino variety at Walmart, was about $8 a gallon. Also, if you are doing the oil change every 3 months, just do the filter every other oil change.
 
been running rotella t 15-40 for three or so years, changed every 4-5k, which is every 4-5 months or so. (its hard to find the 10-30, never thought to check at walmart)
 
they don't have 10-30 rotella T at walmart here, but they do have 15-40. Kinda heavy though...
 
The rusty dipstick and the small milky-mix could be related to simple condensation in the crankcase and a clogged or poor CCV system.
Click to expand...
this for the thread win.

If I only had a dollar for everytime a clueless poster has told someone with an oily airbox that their rings are shot


to the OP FYI there is NO PVC system on these .
 
kastein said:
they don't have 10-30 rotella T at walmart here, but they do have 15-40. Kinda heavy though...
Click to expand...

They still had it at the Walmart here today, but I talked to the "counter dude" and he said with Walmart they just put on the shelf whatever corporate ships them. Corporate tracks sales automatically through the UPC system so there is no ordering by the departments, so you would think they would have some idea what you were sent, what sold, and what doesn't.

Of course, in the sporting goods department they have a whole case worth of .35 Remington on display--I personally know of only one person in our entire county that owns a rifle chambered for .35 Remington, and he hunts with a bow. That ammo has been collecting dust on that shelf for about seven years since I first noticed it.
 
krochus said:
this for the thread win.

If I only had a dollar for everytime a clueless poster has told someone with an oily airbox that their rings are shot


to the OP FYI there is NO PVC system on these .
Click to expand...

Do I get a cookie? I love chocolate chip cookies! :D
 
Of course, in the sporting goods department they have a whole case worth of .35 Remington on display--I personally know of only one person in our entire county that owns a rifle chambered for .35 Remington, and he hunts with a bow. That ammo has been collecting dust on that shelf for about seven years since I first noticed it.
Click to expand...
How serendipitous, Me and a close friend were at the range shooting his 35rem chambered Remington 81 woodsmaster amongst other things earlier today. Down round these parts that ammo would have moved out fairly quickly
 
MT Mike said:
My airbox on my 89 4.0 is pooched out the same way on the bottom. Any ideas on a cheap fix, other than outright replacement?
Click to expand...
You could pop rivet some angle iron/aluminum to the sides of the box, inside or out where ever it fits best. That should keep it from bowing.
 
You could us a piece if threaded rod/Washers/nuts through the box, tighten it the nut up until it straightens out the bow, Just make sure to place it below the filter so it does not get in the way & seal it up with some silicone.
 
You could try a heat gun and reshape it, but not sure how long it might last without reinforcement.
 
garr said:
You could us a piece if threaded rod/Washers/nuts through the box, tighten it the nut up until it straightens out the bow, Just make sure to place it below the filter so it does not get in the way & seal it up with some silicone.
Click to expand...

did this, and bypassed the old pcv hose with one going straight from the valve cover to the airbox. (no yards had the vacuum tube assembly) welded up the busted header, reinforced it, cleaned a good 1/8" of oily carbon from the intake manifold and intake ports, and sealed it all back up with fresh gaskets.

fired right up, and my right foot and butt dyno say it accelerates with far less pedal travel and I should be expecting to be back to at minimum 19.8mpg, maybe even back to the 21.5 I was pulling on summer gas a couple years ago.
 
For the future, you can buy both halves of the vacuum harness from rockauto.com for $18 each plus shipping or from NAPA for $24 each without shipping--last pair I bought I got through NAPA.
 
I just reshaped the air boxes on both of my Jeeps this weekend with my industrial strength heat gun. It must be a good one since it has a warning label advising me not to dry my hair with it. The final results were fine on the air boxes. Just remember to hold the box in shape til cool. Time will tell.
 
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