87mjdriver Posted December 2, 2012 Share Posted December 2, 2012 I have a rusty's cold air intake tube, I just did a oil change to some thinner oil for the winter, ( i just moved to duluth,MN) at the same time I did a valvecover gasket. when I took apart the vacuum tube assembly I noticed a little bit of oil in the tubes, but nothing in the filter I keep an eye on that cause I know its an issue, So on my next drive to work ( a 25 min freeway ride) I noticed my oil pressure was around 55 pounds witch seemed high to me. I get to work and notice oil (3oz.) pouring out of the air filter My first thought is the whole vacuum tube assembly needs to be replaced but could there be another issue? Link to comment Share on other sites More sharing options...
Alexia Posted December 2, 2012 Share Posted December 2, 2012 Two typical causes, one silly and one dramatic. 1.) The lines from the air box to the valve or PCV to intake manifold are possibly clogged. 2.) You should do a compression test on each cylinder. It sounds like there is a failing piston ring. If caught now it could be a swap out the rings job instead of replace the motor job. Unexplained and sudden higher oil pressure usually means something is clogging an oil galley. Such as a piece of metal that broke off somewhere else. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 2, 2012 Share Posted December 2, 2012 Replace the harnesses anyway. YOu know the grommets no longer seal and there's probably plenty of cracks and loose vacuum lines. Be sure to clear out the vacuum fitting on the intake manifold. It can get quite coked up. Renix Vacuum Harnesses The vacuum harness that attaches to the front of the valve cover and includes the grommet/fitting, and is called the front harness, is Napa part number BK 715-1367 http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_7151367_0269070623 The vacuum harness that is closest to the air cleaner, EGR etc, and is called the rear harness, is Napa part number BK-715-1366. http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_7151366_0269070622 The tube from the rear of the valve cover to the intake manifold is part number 715-1365. http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_7151365_0066877355 Revised 09-11-2012 Link to comment Share on other sites More sharing options...
Automan2164 Posted December 2, 2012 Share Posted December 2, 2012 Wasn't there a procedure for correcting the PCV system and modifiying the valve cover to stop/slow the blow by? Rob Link to comment Share on other sites More sharing options...
skidoo_j Posted December 2, 2012 Share Posted December 2, 2012 Yeah Cruiser has a procedure for removing the towers in the valve cover, cutting them an inch shorter and drilling a whole in them. I did his procedure on my 89, have had no adverse effects. I did however find that in 89 jeep had already drilled the wholes in the towers, so I just cut mine 3/4". I did not have any blow by prior to doing the mod, I just did it because my valve cover gasket was leaking. What I did find out is that by replacing all the vacuum hoses the diameter of the hose from VC to manifold is very important, too big and it got too much air and it pulled enough air through the valve cover it would raise the idle. http://comancheclub....r-vent-options/ Link to comment Share on other sites More sharing options...
cruiser54 Posted December 3, 2012 Share Posted December 3, 2012 Wasn't there a procedure for correcting the PCV system and modifiying the valve cover to stop/slow the blow by? Rob Cruiser’s Valve Cover Mod Most early and even later Renix 4.0s could be bothered by excessive oil in the air cleaner box. A fix from my old days as Service Manager at a Jeep dealership follows. Information was provided to me from a buddy at JeepTech during those days. I don’t believe it ever came out in a Technical Service Bulletin. Remove the valve cover and turn it over. Next, remove the fluted tubes that are now facing you by removing three screws on each. Chop 1 inch off each of them. Then, about a half inch up from the area where you just sawed them off, drill a half inch hole in the tubes so the holes will face the rear of the valve cover. Clean and de-burr/sand all rough edges nicely, clean with solvent, and reinstall. Don’t be concerned about the chintzy gaskets that will probably crumble into oblivion when you remove the fluted tubes. They can go back together without gaskets. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 3, 2012 Share Posted December 3, 2012 I'll post an image of the valve cover flutes before and after if someone shows me how....... Link to comment Share on other sites More sharing options...
Des88MJ Posted December 3, 2012 Share Posted December 3, 2012 Glad I stumbled upon this, I've been looking to replace the cover for the oil issue, now i'm just going to cut the towers, and replace the gasket. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 3, 2012 Share Posted December 3, 2012 Glad I stumbled upon this, I've been looking to replace the cover for the oil issue, now i'm just going to cut the towers, and replace the gasket. Make sure the CCV lines are good, too. Enjoy your Jeep. Stumble on this: http://www.cherokeeforum.com/f51/cruiser54s-mostly-renix-tips-153657/ Link to comment Share on other sites More sharing options...
HOrnbrod Posted December 3, 2012 Share Posted December 3, 2012 "A fix from my old days as Service Manager at a Jeep dealership follows. Information was provided to me from a buddy at JeepTech during those days. I don’t believe it ever came out in a Technical Service Bulletin." I'd like to emphasize that hacking off the valve cover vent towers should be done only a last resort. I've never had to do this. As Cruiser states, first clean and/or replace the original CCV lines, elbows, valve cover grommets, and clear or replace the metered orifice elbow fitting. If this doesn't help, upgrade to the larger ID HO 1994 and up CCV system. This has always stopped blow-by problems for me w/o resorting to hacking the vent towers. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 3, 2012 Share Posted December 3, 2012 I agree with the cleaning of the CCV tubes first. But, the hacking of the tubes was an unpublished and recommended procedure from Jeep Tech when the Renix Jeeps were new. Link to comment Share on other sites More sharing options...
Des88MJ Posted December 4, 2012 Share Posted December 4, 2012 Make sure the CCV lines are good, too. Enjoy your Jeep. Stumble on this: http://www.cherokeef...ix-tips-153657/ Another good thing to stumble on! Thanks for that, my electrics like to act slightly strange once in a while. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 4, 2012 Share Posted December 4, 2012 Another good thing to stumble on! Thanks for that, my electrics like to act slightly strange once in a while. Free and easy, too. Link to comment Share on other sites More sharing options...
87mjdriver Posted December 5, 2012 Author Share Posted December 5, 2012 Ok so doing some looking around, aparently the little tube that goes from the back of the VC to the intake manifold came off at the intake. That fixed the oil coming out of the filter. When I get the money I'm replacing all the tubes anyway. Besides all the grommets on the valve cover leak. But I am still showing 55 to 60 lbs. of oil pressure. It seems a touch high but not sure if its a concern. I just did an oil change to 5w-30 Mobil 1. And a Fram oil filter which I just read in a post below is questionable. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 5, 2012 Share Posted December 5, 2012 Ok so doing some looking around, aparently the little tube that goes from the back of the VC to the intake manifold came off at the intake. That fixed the oil coming out of the filter. When I get the money I'm replacing all the tubes anyway. Besides all the grommets on the valve cover leak. But I am still showing 55 to 60 lbs. of oil pressure. It seems a touch high but not sure if its a concern. I just did an oil change to 5w-30 Mobil 1. And a Fram oil filter which I just read in a post below is questionable. Ditch the Fram. Link to comment Share on other sites More sharing options...
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