WNC_MJ Posted April 14, 2009 Share Posted April 14, 2009 I have a dilemma... my Comanche ('88, 4.0L, 5-spd) is blowing large quantities of oil into my airbox via the front vent tube from the valve cover! I recently replaced the valve cover gasket and cleaned out the 'ports' leading to the vents remembering to replace the metal 'flaps' and gaskets. This was happening prior to me changing the gasket (I recently got this truck) but seems to have gotten worse, probably due to the lines being clean and unrestricted. It's blowing enough oil that after driving 100 miles I have to put 1/2qt. into the engine! HELP!!! :help: Link to comment Share on other sites More sharing options...
sinkrun Posted April 14, 2009 Share Posted April 14, 2009 Hi, I had the same problem which is very common on these early 4.0. I did the same cleanout you did and replaced all the cvc lines going to the intake and still no fix. I found a post on here where a guy replaced the valve cover with a 97 and up 4.0 as they have a full length baffel not the towers as in the old ones. I used a 2002 steel cover got it of ebay like 20.00 but you do have to use the newer type gasket to match the valve cover EXPENSIVE. Also will have to do some changing of the vacum lines. If you get a cover make sure it has the gromets and inserts to put your new hoses on. You will also have to change the size of the brass nipple on the intake to match the large breather hose on the newer cover. There is a nice write up on here if I can find the link I will post it has pictures and details much better than I can explan. Oh and yes this was 5000 miles ago and not a drop of oil in the box. LEt me know if you have any questions. Link to comment Share on other sites More sharing options...
WNC_MJ Posted April 14, 2009 Author Share Posted April 14, 2009 Ugh... so there's not really an easy fix... wonder why it started 'all the sudden'? Link to comment Share on other sites More sharing options...
sinkrun Posted April 14, 2009 Share Posted April 14, 2009 Its not to bad a fix probly took me about 2 hours at the most and I am not a whiz mechanic. I tried to find the post but no luck maybe some one else has it bookmarked and can chime in. If you want to learn more search Blow by in the search section lot o reading. Link to comment Share on other sites More sharing options...
ratrapp Posted April 14, 2009 Share Posted April 14, 2009 i did the valve cover fix as well.not a drop of oil in the air box.i spent $20 on a cover,$35 on a gasket and $1 on a fitting.it is well worth the effort and isn't as hard to do as you may think. Link to comment Share on other sites More sharing options...
mjeff87 Posted April 14, 2009 Share Posted April 14, 2009 Here ya go......... ;) Jeff viewtopic.php?f=2&t=12871 Link to comment Share on other sites More sharing options...
WNC_MJ Posted April 15, 2009 Author Share Posted April 15, 2009 Great! Thanks guys! I took the time and checked all of my vac lines today and cleaned them thoroughly. I found that one of the EGR tubes was clogged, but other than that all was well. Until I can get another VC from a JY and do the swap, I've put on a small conical filter to keep the oil from going into my airbox again. I'll try to post photos of it below. Link to comment Share on other sites More sharing options...
BLHTAZ Posted April 15, 2009 Share Posted April 15, 2009 Great! Thanks guys! I took the time and checked all of my vac lines today and cleaned them thoroughly. I found that one of the EGR tubes was clogged, but other than that all was well. Until I can get another VC from a JY and do the swap, I've put on a small conical filter to keep the oil from going into my airbox again. I'll try to post photos of it below. That's not a good idea. You are going to have oil all over your engine by doing that :ack: The newer model VC may help, but your problem could be (if high mileage and not maintained well) that the rings are bad and you are experiencing blow-by. If that is the case, then some major engine work is going to be in order. Let's hope the VC trick works for you too. :cheers: Link to comment Share on other sites More sharing options...
Pete M Posted April 15, 2009 Share Posted April 15, 2009 I tried the little filter idea and oil just got everywhere. :( My "fix" was to run a hose from the valve cover into a gallon washer fluid jug, then another hose running from the jug into the air box. It traps the oil and keeps it out of the filter. But I've heard that a stretched timing chain can cause horrendous blowby. Someday this summer I'll be replacing it to see if it helps. Replacing the chain can't be a bad idea for a 200k engine anyways, so it's no loss if it doesn't work perfectly. :D Link to comment Share on other sites More sharing options...
WNC_MJ Posted April 16, 2009 Author Share Posted April 16, 2009 I've also read on here about a VC replacement with a newer one... I'm going to price the parts from a JY and possibly do that soon. Thanks guys! Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now