How can blowby cure itself?

[1987Comanche]

Here's the story. I picked up my '90 MJ 4.0L about 6 months ago from the PO (who was also the original owner). The miles were pretty low (117K) and he parked it because of electrical problems. I dragged this gem home and have been driving her to work and back since (about 50 hwy miles per day...I'm up to 121,600 now). Until about 2 weeks ago I'd find a light brown puddle every day at work where the oil was spitting into the airbox and leaking out the drain hole in the bottom. I put a VC from a '96 4.0 a few months ago and that helped some but I still had a decent amount of blowby. I did as much as I could, shrugged my shoulders and said the heck with it.

About 2 weeks ago I noticed that this particular puddle was no longer forming (I still have other oil puddles but no tell tale light brown one from the airbox). Any ideas why the blowby would cease to be a problem?

[Geonovast]

Magic.

 

Same reason new spark plugs fixed my tach, I would imagine. :dunno:

 

It's possible that the new VC did indeed fix it, and the puddles you saw after changing it were from the oil still in the lines getting sucked out.

[jimoshel]

Sludge? Sounds like maybe the PO didn't drive it much and sludge, carbon built up. Your driving loosened it and blew it out. Suggest you change oil and filter(sans Fram) ASAP.

[1987Comanche]

Magic.

 

Same reason new spark plugs fixed my tach, I would imagine. :dunno:

 

It's possible that the new VC did indeed fix it, and the puddles you saw after changing it were from the oil still in the lines getting sucked out.

I changed the VC in December and both hoses were clear as I had to swap them both (went from AL VC to stamped steel). I haven't touched the top end since.

 

Sludge? Sounds like maybe the PO didn't drive it much and sludge, carbon built up. Your driving loosened it and blew it out. Suggest you change oil and filter(sans Fram) ASAP.

The inside of the engine was definitely carboned up. When I pulled the VC I spent 2 hrs scraping crud from the top of the cyl head. I probably had a 12oz Coke can full of carbon when I was done. The oil pan and timing cover were pretty bad too. When I replaced the RMS again a few weeks ago I found another 10-12 little chunks of carbon in the oil pan. From what I can tell the truck went about 7K miles in the last 3 years they had it. Perhaps stuck rings that finally freed themselves?? I've been running an AC Delco PF13 since bringing her home.

[akamcbird]

ever heard that term....

 

its a jeep thing, you wouldnt undestand.

 

i don't understand, but half the problems or squeeks or whatever i have, go away before i find the cash to repair or track them down.

... and i don't mind...

 

just shrug and say "meh, its a jeep thing"

[-600JeepMJ]

:agree: :nuts: Not only a jeep thing, I get the same thing at work were a pilot will tell me some thing is wrong with the airplane. And we will spend a crazy amout of time working on it only to find nothing wrong. :wall:

[akamcbird]

reason 426 not to fly.....

 

were do you work?

[jimoshel]

Read some of the pilot write ups and maintenance replies. You'll never feel the same way about flying again. EX,

Pilot: Gear squeaks when retracting.

Maint. Don't retract gear.

Pilot: Altimeter reads off at 30,000ft

Maint: Unable to duplicate problem on ground.

Pilot:A/C doesn't work when stew is in cabin.

Maint: Make stew sit in Co-Pilots lap.

There is a entire book dedicated to these entries. :rotf:

[-600JeepMJ]

:hijack: I work on 40 year old military airplanes, at what use to be know as Kelly AFB. Now it is called Lackland AFB the gate way to the airforce. we just call it wackyland.

 

:nuts: for every one hour of flight time maintenace does ten hours of work.

[jimoshel]

Kelly and Lackland used to be 2 seperate air bases. Did they consoladate them or what?

[Oizarod115]

ran out of oil. :smart:

[Dave Stark]

Pilot complains tail rotor is vibrating in the pedals, mechanic goes to the back of the aircraft makes some noises with his tools (doesn't actually do anything). Then he tells the pilot to start it up, pilot claims he fixed & there are no more vibes.....

 

I actually witnessed this on helicopter i that worked the engine on. :nuts:

[-600JeepMJ]

Kelly AFB got hit by BRAC. Boeing took over the south east side and does the depo work on the C-17 and KC-135

 

the city of San Antonio took over north east side of the base and now calls it "Port San Antonio" http://en.wikipedia.org/wiki/Port_San_Antonio

 

 

Lackland AFB took control of everything on the west side of the runway.

 

 

the best one I have had is when the pilot wrote up the seat cushion was uncomfortable. I was a slow night for us, so the lead crew chief sat down and took a nap in the seat. signed the write up off as removed and replaced "O6 stick actuator", eight hour ops check good.

 

O6 = full bird Colonel.

stick actuator = pilot

[STERLING STINGER]

:agree: :nuts: Not only a jeep thing, I get the same thing at work were a pilot will tell me some thing is wrong with the airplane. And we will spend a crazy amout of time working on it only to find nothing wrong. :wall:

just goes to show y i will never fly... :shake:

[kastein]

Here's the story. I picked up my '90 MJ 4.0L about 6 months ago from the PO (who was also the original owner). The miles were pretty low (117K) and he parked it because of electrical problems. I dragged this gem home and have been driving her to work and back since (about 50 hwy miles per day...I'm up to 121,600 now). Until about 2 weeks ago I'd find a light brown puddle every day at work where the oil was spitting into the airbox and leaking out the drain hole in the bottom. I put a VC from a '96 4.0 a few months ago and that helped some but I still had a decent amount of blowby. I did as much as I could, shrugged my shoulders and said the heck with it.

About 2 weeks ago I noticed that this particular puddle was no longer forming (I still have other oil puddles but no tell tale light brown one from the airbox). Any ideas why the blowby would cease to be a problem?

Same thing here, I was blowing a quart of oil out the RMS and airbox every 150 miles till a week ago. I fixed it by reconnecting the front CCV hose to the airbox properly... mine had come loose so I had no real vacuum on it. I still have a little bit of an RMS leak but nowhere near as bad now.

 

ran out of oil. :smart:

This could also be it :dunno:

 

Maybe a bit of that carbon you found got stuck in the CCV orifice or something? Try removing those lines and hosing them out with throttle body cleaner?