BIG OIL from dipstick tube - blow-by? And NOW WHAT?!

1991 XJ, currently 204K miles. I've owned it for about 8-9 years; nothing ever done to engine AFAIK. Been leaking ... a LOT ... for some time now. Last summer, I replaced the elbow gasket and the rear main (needed help with that, but that's another story).

Improved, but still leaked. Oil seemed to be spraying from the dipstick tube. So, novel diagnostic solution: 1) remove dipstick; 2) put some plastic hose over dipstick tube; 3) drill hole in cap of empty soda bottle and anchor it with zip ties in an out-of-the-way location; 4) run tube to soda bottle. The thinking was it would collect the oil and eliminate the leak, which presumably was coming from worn rings resulting in oil blowing out the tube.

Funny thing: no oil in the tube or bottle. Still leaking, but better. Assumption: Can't be the blow-by, right? Since I only drive 10 miles/day, I ignored it and added oil every so often.

This week, it dawns on me that I put the tube on VERY tightly and probably just created a closed pressure system that wouldn't allow oil to blow that way. So I loosen the bottle cap a bit to see, and HOLY CRAP. Nearly filled the bottle in an hour of 65-mph driving. (Yep, I tightened the cap back up.)

So now I have two questions:

1) Is this proof that the rings are so bad that I need a reman/rebuild?

2) If question #1 is "yes", would you replace an engine on a Jeep that has a 3-year-old clutch, 7-year-old OME suspension (that I LOVE), and 4-year-old radiator/T-stat/hoses/belt, and good rubber... BUT it slips a little in 4WD, needs rear brakes, still has original front & rear diffs, a cracked windshield, a crappy stereo, a sagging head liner...

So what's a guy to do? Is it worth the $5K to have a rebuilt put in (I'm not confident I can handle that much work, so my neighbor, who has a shop, would be the installer)? Or should I just pull the suspension and put it on an XJ with lower miles?

I LOVE my Jeep. What would y'all do?

As a 27 year experienced tech, I'll give you this advise; I'd suggest that you take it to a reputable shop and have them do a bumper to bumper inspection. Tell them your situation and have them make a list of everything they find that needs attention, they can prioritize it for you by urgency of repair. They will likely offer a quote too.

This will give you a good idea whether or not to fix the engine.

They should charge about one hour labor. best 100 bucks you can spend.

I would take a good look at the CCV system 1st.
The rear port should be clear and have vacuum on it.
The front port goes to the air box and the hose should be good.
There is a baffle inside the valve cove which gets crudded up and usually requires a good cleaning.

Next on the list would be a compression and leak down test to see how bad the rings are.
204k is long in the tooth, but if the rest of the vehicle is in good shape, it might be worth having it rebuilt or find a good used one if it's actually bad.

-Ron

this. before anything else...
the last xj I picked up had some pretty nasty oil in the air filter issues, along with it oozing out from under the oil filler cap all over the cover. turns out the rear ccv line was clogged SOLID. it was so bad that I could not clear it out with spray parts cleaner and compressed air, just went and bought a new dorman hose off amazon.
after that, no oil at all in places it shouldn't be.

WB9YZU said:

I would take a good look at the CCV system 1st.
The rear port should be clear and have vacuum on it.
The front port goes to the air box and the hose should be good.
There is a baffle inside the valve cove which gets crudded up and usually requires a good cleaning.

-Ron

Click to expand...

Yeah, I'd check for the obvious problem areas that are cheap to fix like the rear CCV breather to the intake. R/R as needed. For cartooned up rings and a decent cleaning I've always liked Auto RX. I know some folks hate the stuff but its worked well for me. Do a compression check before and after. If your compression is low after 2 clean cycles and you're still blowing oil after any CCV repairs probably time for a rebuilt motor. I'd probably look to a junkyard engine than a $5K engine. Mine's an 01 and has 316K on the engine. I've had to pull the head twice but the bottom end looks like it will break before it wears out.

WB9YZU said:

I would take a good look at the CCV system 1st.
The rear port should be clear and have vacuum on it.
The front port goes to the air box and the hose should be good.
There is a baffle inside the valve cove which gets crudded up and usually requires a good cleaning.

Click to expand...

This! The purpose of the CCV is to remove combustion gases and pressure from the crank case.

and your severe oils leaks were likely the result of the crankcase not venting properly.

crappy CCV system performance makes seals fail.