Oil from fill cap

[SW86]

everytime i get on the gas to pass someone or get up speed in a hurry, theres always oil coming out of the oil fill cap and air tube hole. is that normal or could there be an issue there? thanks

[jimoshel]

Blow by between the piston(rings) and cylinder walls is building up pressure in the crankcase. Also check the PVC valve and hose to make sure they're not stopped up. Check the oil baffle around the filler hole and make sure it hasn't broke off. Quit stepping on the gas or getting in a hurry.

[SW86]

there was some gunk in there but never enough to block off the whole hole. its dark though so ill give it another look tomorrow to make sure. the baffle is good. ive had to replace that cap before. it just started this and its gotten really bad. to the point of leaking down out of the air box and spraying all over the underside of the truck.

 

i can explain the flooring it business. as of late a lot of slow people have been pulling out in front of me. so i have to pass because it really pisses me off to be stuck behind them. it also seems everytime i do theres someone coming the other way. hence hurrying up. otherwise id be cruisin' along without a care in the world 8)

 

 

edit: found this link with a little more searching

 

viewtopic.php?f=2&t=29406&p=295556&hilit=oil+blow+by#p295556

 

might give that mod a go.

[exjay33]

Is this the 4 cylinder by chance ? If so hole in a piston which they are famous for . When you remove oil cap is it white and foamy looking ? If so plan on a rebuild won't have alot of life left.

[SW86]

nope. 4.0.

 

its gotten really bad. to the point of pouring out of the air box at the bottom and covering the whole underside of the truck. the hoses were clean and the valve inside the air box was slightly clogged but i cleaned it out. are both of those little hoses on the back of the air box supposed to have pressure/air going through them? the one coming from the valve cover does strong but the one running out of the box has nothing. the big hose running from the valve cover on the front has slight suction. should it be more?

 

I'm trying to go wheelin' this sunday so it'd be nice if i could drive it there. thanks for the help :cheers:

[Jerry Forrester]

It is time.

What time is it?

It is time for either an engine rebuild or another engine.

The one you have now is junk.

It either has a hole burned through a piston or a hole burned down the side of a piston.

I'll bet when it's sitting there idling with the oil fill cap off it looks like a steam locomotive.

Sadly, you need an engine.

BTDT

later, Jerry

[SW86]

well its doing it less now and the smoking from the VC has lessened. the motor feels strong to me but ill do a couple more things to see if i can get it to quit. if not, motor rebuild it is then. thanks

[SW86]

update. i swapped to the 97+ valve cover today and so far everything seems good. ive pushed it a little getting up to 70 in a hurry and there was very little to no oil in the air box after that drive. as to where with the old cover there would be oil coming out of the fill cap and air box. ill give it an interstate run to really put it to the test later. ill edit this with my results

 

here's a link i found after a little diggin on the matter

 

viewtopic.php?f=2&t=12871

 

 

EDIT:

interstate test was great. usually after running 65-70 mph there'd be oil dripping off the truck but there wasnt but a tiny spot on the filter. I'm sure it was just leftovers in the tubes i left. this was well worth the time and money! :thumbsup:

[ratrapp]

it's amazing what a valve cover redesign can do.i did it myself on my 88 mj and to be on the safe side i changed it on my gf's 95 zj as well.