Hooniverse Garage: 1969 Jeep Wagoneer Intake Manifold Fix

We’re back in the garage again, working on the Wagoneer. It’s well known that Jeeps leak oil, but there’s a spectrum from “marking their territory” to “British Leyland” to “Exxon Valdez”. My Wagoneer was leaking so much down the undercarriage it’d actually blow up the back of the car and accumulate an oil slick on the tailgate after any long drive. Good for rust prevention, bad when parking in friends’ driveways. It leaked from the rear main and the timing cover, but the biggest emitter was the back side of the intake manifold. Time to rectify that…

I’d actually attempted to re-seal it a couple years ago, but generally screwed up the procedure. Here are a few tips I’ve learned from previous screwups:

  • If you’re debating whether you actually need to remove something that’s kind of in the way (e.g. the distributor), do it. Whatever time you think you’re saving by not pulling it isn’t worth the hassle of wrestling the intake in/out with greater difficulty. Clear the runway.
  • I hint at it in the video, but make sure that coolant is all the way drained. I once thought it was all gone, only to hear a sickening gurgling/splashing sound as I busted the manifold loose. Coolant can linger in the intake crossovers, only to pour right into your crankcase as you pry the manifold up. I soaked it up as best I could, then basically did three oil changes in a row to get it all out.
  • Typically V-engine intake manifold gasket sets come with little gasket pieces to go along the front and back of the block. These were the source of the oil leaks on the Wagoneer (and my Falcon). While prepping for this job, I double-checked a video from our friends at Scared Shiftless (they’re working on the Wombat Mercedes Wagon Hemi swap project) and they recommend placing these bit directly in the trash upon receipt.
  • It may or may not be mandatory, but I like the idea of letting the freshly sealed assembly sit overnight to let adhesives bond and cure before they’re subjected to the heat, water, gas and oil of a running engine.

Oh, and for the record, the manifold’s sealed up nicely now. With that oil shower stopped, it’s apparent my next biggest leak is actually the transmission.
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  1. Scoutdude Avatar

    Whether or not you should just throw the end seals away depends on the type of end seals on a given engine and in a given gasket set. Some have quite thick cork end seals and they are not well replaced by a chemical solution. For those the best option is to firmly glue them to the thoroughly cleaned block, but a thick bodied sealant like the Right Stuff can work IF you clean the surfaces properly and are careful when placing the manifold on the block. For the thin cork gaskets it is usually best to toss them and use a quality sealant like the Permatex black silicone or the Right Stuff. Again proper cleaning of the surfaces and careful installation of the manifold is required. For those with rubber end seals I recommend using them and a thin coat of a thin bodied silicone like the Permatex black. No matter which chemical solution you use proper cleaning of the surfaces is key to creating a bond that will actually seal. A little oil film in places will prevent a bond from occurring and result in a leak. A physical gasket that is crushed will create a seal on less than perfectly cleaned surfaces.

    1. NapoleonSolo Avatar

      I’ve read a couple of times that it might be a good idea to let some of these sealants cure fully and then re-torque depending on the actual configuration.

  2. Dabidoh_Sambone Avatar

    Oil slick on your tailgate huh? I try to keep a spotless car but every once in a great while I’ll notice tiny spots appearing on my windshield while driving in traffic – but by then it’s too late: my car’s got a film of oil on it. What a total pet peeve. Maybe you should write in white shoe polish across your back glass “OILY MIST – FOLLOW AT OWN PERIL” especially for motorcyclists in nice leather gear.