[9361]

Well I think I may have finally killed the old 258.

On the weekend I changed the intake/exhaust manifold gasket and then decided to go out wheeling. I got the Jeep stuck in the mud and it took another Jeep with me to pull me out. I wasn't sunk too deep (maybe 4 inches below the oil pan), but some water may have got into the air pulse tubes for the emissions (as there are a couple of holes in them now). I had turned the engine off and had it off for about 5 minutes, and when i turned it back on there was a huge cloud of smoke, kinda blue/white. Then once i got un stuck it was blowing a bit of blue smoke the rest of the trail. It seems it would build up, cause when i'd turn the engine off for a few minutes and then turn it back on, there would be a cloud of smoke. When i was trying to get it unstuck i was reving it kinda high(about 3000-3500) for about 3-5 seconds at a time, 6 or 7 times.

Anyway i drove it home, and it seemed to be fine. cause i let it sit for a bit at the house and then turned it back on and no smoke. Figured something may have just got in the exhaust some how and driving on the road got it out. I noticed the oil was down a bit too (down about 3/4 of a quart), so i topped it up (it doesn't ever burn oil hardly though so i thought this was kind of weird).

Then today i was sitting at a red light for a couple minutes, and when i went to take off, there was another big cloud of smoke. When i got home i checked the oil again and its down about 1/2-3/4 of a quart. I've only drivin it about 20 kms in the last couple days, but I've let it warm up some every morning too, so i thought that could have been a cause for some of the oil consumption.

The idle has been a bit high for a while now too (sits at about 900-1000). I played with the idle screw a bit the other day when i did the gaskets, so i thought that may have been a cause for the high idle.

So any ideas?

I'm thinking the worst and that my piston rings are fried. I didn't think it was possible to kill these engines. FYI this engine has about 240,000 km on the odomitor. I changed the oil about 2500 kms ago, running 10w30. It's been pretty hot here lately too, and had a really hot drive home from vacation a few weeks ago; 30+ degree weather for about 350 km drive.

The coolant is fine, no oil in it, still looks nice and green.

Thanks in advance for the help. Let me know if you need any other info.

 

[9361]

BTT

 

[Jim_Lou]

I doubt that the mud incident killed the engine. They do wear out eventually, you know. The big cloud probably brought the oil burning to your attention, but you might have broken a ring or two. Do a compression check and see what you get, but my guess is that you're do for a rebuild, just from the mileage (kilometerage?)

 

[Pete88YJ]

Well, if you're still running the pulse air tubes, I guess we can ask some more questions --

How much of the rest of your system is "stock"?

Assuming you've already looked inside the air cleaner....

Do you still have the vent and filter for the blowby in the rear of the air cleaner? The high rpm blasts could have pumped a whole lot o' oil into your air cleaner, and thus into your motor, causing the smoke.

I know before I rebuilt it, my old 258 had high mileage, and so much blowby that I had to disconnect it from the air cleaner, and rig up a catch can and vent to catch it all. She still ran great, but man it pushed a lot of oil out that rear valve cover vent.

Could come in through your PCV too. Worth a look.

Good luck
Pete

 

[9361]

I think my 258 is the only Jeep engine i have ever seen that doesn't have blowby. Air filter is bone dry. and i just replaced the tubes that connect to the PCV valve. i popped the tube off at the carb and there is no traces of oil at all.

i haven't checked the compression but i will tomorrow and let ya know.

thanks for the suggestions

 

[RRich]

Just a thought - sitting in the water - water got in the oil, thinning it out, diluting it enough to let it slip past the rings?
Try an oil and filter change.

It takes a surprisingly long time to get even a small amount of water out of the exhaust - could be the smoke.
Try something - at the lowest part of the muffler, punch a small hole in it, like a 1/4" hole. You may hit water! (Got in through the AIR tubes and up the tailpipe. When you put a tailpipe from a hot exhaust, the cooling effect causes it to suck water in like crazy! - more than you'd think.)
Start and run it - water may blow out the hole.
You can always plug that hole with a sheet metal screw later.