plenum leak / death flash issue?

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May 11, 2010 | 12:09 PM
  #1  
So I have heard mention of these in other posts I have been reading. Since its on a large number of trucks I thought I would look into the faq on this.

I am fairly alarmed because I know that from time to time while sitting at a read light I noticed that the 318 does make some ping/ticking noise but eventually goes away. Other than whats in the faq, is there any else I should be aware and cautious of while trouble shooting this to see if I do have a plenum leak?
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May 11, 2010 | 03:02 PM
  #2  
if you have a magnum motor you got the leak end of story, if your worried about time just find a used manifold and fix that one and then swap
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May 11, 2010 | 03:22 PM
  #3  
Im in the process of fixing my plenum leak. Also is your truck burning alot of oil. Just take off your throttle body and with a small flashlight look down into the intake and look for pooling oil. There is a 100% chance that your truck will eventually blow the plenum gasket.

http://www.hughesengines.com/Index/p...2&partid=22220 Here is the link to the Plenum Reinforcement kit from Hughes.

I would also recommend changing the thermostat, distribution cap and spark plug wires while you are down there. If you have some extra cash i would invest in a new timing chain.
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May 11, 2010 | 03:45 PM
  #4  
I drove home for lunch and then came back to work. And I smelled oil. I dont know if its cause I just changed oil this weekend and didnt do a wonderful job of wiping up all of the mess from dropping the filter or not.

I just bought this truck 2 weeks ago this friday so I dont have a lot of comparison yet. But I will look down through the throttle body and check for oil. If nothing else I can follow the instruction about testing for plenum leaks I have the vacuum gauage and everything I think I will need.
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May 11, 2010 | 03:56 PM
  #5  
also get a high flow cat as the plenum clogs the cat
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May 11, 2010 | 04:46 PM
  #6  
I was planning on just knocking the guts out of the cat :P
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May 11, 2010 | 09:24 PM
  #7  
Got home from work and let the engine cool a bit. Then popped open the hood and air cleaner. Opened up the butterflies and I could definitely see on the PCV side that there was some black coloration there. Also saw what looked like carbon or burned oil in the crevices of the metal. But definitely no pooling or collection of oil anywhere. I then had my neighbor (A car nut too) look inside. He didnt think it was a problem either. The truck has 264000 miles on it and is still in pretty good shape. Whoever had this truck last obviously did a fairly good job or else it wouldnt still be running this well.
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May 11, 2010 | 10:59 PM
  #8  
give your truck a good seafoam
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May 12, 2010 | 12:06 AM
  #9  
I know seafoam makes the fuel system cleaner. Is that the one you are talking about? Or do they make a oil additive as well?
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May 12, 2010 | 09:30 AM
  #10  
Unless a PO fixed it, your plenum is definitely blown after that many miles. You can't see enough by looking down the TB. I tried that approach, thought mine was fine to, all I could see was a very thin sheen of oil, no pooling, which I was told was normal by several guys on this forum. You just can't see the corners well enough to see where the oil "hangs out".

Finally bit the bullet and dived in with the Hughes kit... and it turned out I had half a quart of oil in the manifold. And this was at 60,000 miles-ish, and I am 99% certain it was blown at 50,000 miles when I bought it.

If it is a Magnum V8 from 1994-2002, and it hasn't had the fix, it is blown. No doubt about it.
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