JStone Posted January 21, 2021 Share Posted January 21, 2021 Just picked up a 1990 Comanche for a guy from a guy from a guy none who had interest in taking real care of it. It was clearly having oil leaking issues but as is such as a mis treated 31 yr old truck. But after the test drive I seen a good amount of oil on top of the valve cover (which is new and hard plastic which I find odd) Drove well from St George to SLC and needed over a full qt on the trip. I just barley ordered a new valve cover gasket and my question is would it be worth it to just change the cover to a full aluminum? And 2 is there possibly an issue with the pcv not pulling vacuum? Causing the oil to come out the side of Valve cover Link to comment Share on other sites More sharing options...
eaglescout526 Posted January 22, 2021 Share Posted January 22, 2021 Little 2.5L history. Since its introduction in 1984. It has always had a plastic cover until 1991, two versions of the cover can be found, one with the AMC logo and the other without. Now since yours is a 90, it is not supposed to have that PCV in the front hole. It is supposed to be a pipe that goes to the airbox in which the intake pulls in the fumes from both holes of the valve cover to burn off any unused gases. So the valve they have in there is wrong and could be posing a problem. The other thing that can cause an oil leak is the crappy oil fill caps. The solution to this is to get a bad bike tube, cut to fit in between the lid and the gasket and it will create a tighter seal at the fill hole. Changing to aluminum is easy to do, but you have to find one and its hardware to use, otherwise you might have sealing problems using the plastic valve cover bolts. Personally, it is easier to keep the original hard plastic cover than swap over just because you have to make some mods and get new vacuum line for the aluminum cover. There is a write up somewhere on here about swapping covers. But if you swap the valve cover and get some RTV and put it on the under side of the cover real good and then install the gasket, you should get a damn good seal with a few leaks here and there because plastic was a bad idea for a valve cover. I only say such as my cover will leak oil at the gasket, but not in a significant amount to worry me. Link to comment Share on other sites More sharing options...
JStone Posted January 22, 2021 Author Share Posted January 22, 2021 Suuuuper good tips!! I’m gonna dive into it tonight and figure out what I need to do to re-pipe that fronter hole ill keep the plastic cover (for now) and change the gasket and see where that gets me. I found a few vacuum diagrams on here. Is your Jeep similar? Like I could reference a picture of yours, no worries either way I can read schematics. New to this forum so I really appreciate the tip! Link to comment Share on other sites More sharing options...
eaglescout526 Posted January 22, 2021 Share Posted January 22, 2021 Mine is as stock as stock can get so sure, here’s a pic: The vacuum on these engines can be a little confusing especially at the T-body and the air bonnet. So if you need pics around there just let me know. Link to comment Share on other sites More sharing options...
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