4.6L (1996-2004 Modular) Mustang Technical discussions on 1996-2004 4.6 Liter Modular Motors (2V and 4V) within.

Burning oil.

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Old Oct 5, 2008 | 10:18 AM
  #1  
NotStok's Avatar
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Default Burning oil.

So last night i'm driving home from work, when I get to a light and there's a really odd almost burning smell coming in my windows. I didn't really think much about it, but decided i'd check the oil level today. To my dismay, the reading is..not good. It looks like the car has burned or consumed a quart and a half of oil, maybe more, and it's billowing quite a bit of smoke when idling.

I don't beat on this car, but did buy it with 44k miles this past February. It's now about to roll over to 60k. Mods are very light, just an O/R X and catback, with a K&N filter other than my rear. I don't know much about the car's history prior to me owning it, other than I bought it completely stock. For all I know, someone could've been spraying the thing to death, then put all the stock parts back on. I know that they gutted the radio while owning it, then just stuck the stock head unit back in.

I'll be doing a compression test today, needless to say. Any suggestions of things to check? I'm kinda worried about my motor.

What PSI should I be looking for?

Last edited by NotStok; Oct 5, 2008 at 10:25 AM.
Old Oct 5, 2008 | 11:37 AM
  #2  
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Update: There is burnt oil on plugs from cylinders 6 and 8.

Hooray. About to check compression.
Old Oct 5, 2008 | 11:43 AM
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I would guess valve guides or a stuck PCV.
Old Oct 5, 2008 | 11:49 AM
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+1 on what defcon said. But how many miles does it take to burn a quart?
Old Oct 5, 2008 | 11:55 AM
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Mine has bad Valve guide seals (or valve guides I'm not 100% sure), and it smokes on startup but thats it.

Its really starting to **** me off, but I know it wont really hurt anything. So I am just going to wait until a later date to fix it.
Old Oct 5, 2008 | 01:39 PM
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Compression test yielded 200psi across every cylinder except 5, which only made 155psi.

I'm going with a bad ring. It's just odd that cylinders 6 and 8 plugs are covered in burnt, sticky oil.

Ugh.
Old Oct 5, 2008 | 01:41 PM
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well that is unfortunate, what did the #5 plug look like?
Old Oct 5, 2008 | 01:48 PM
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I'm assuming you did a wet compression test?? If you did, and got those numbers, then it's more than likely your valve train that's causing the leak.. Have you taken your PCV off, just to make absolutely sure that it's not the culprit as well?? Having a clogged, or stuck PCV can cause excessive pressure down in the crankcase, and cause a little bit of blow-by by virtue..


Even though there was oil on 6&8, doesn't necessarily mean that they are truly bad.. You could do the compression test again, to see if you can replicate the results, and if you do, then you'll know that #5 is where you should start looking..




JT
Old Oct 5, 2008 | 10:00 PM
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Yeah, I wet tested it, which definitely shot the pressure up. I haven't taken the PCV off, either. All I did was add oil again, and drive it to work, this is my DD after all. I don't know how much damage i'm doing driving it.

Ugh.

Edit: defcon, the number 5 plug looked fine.

Last edited by NotStok; Oct 5, 2008 at 10:23 PM.
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