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Discussion Starter #1 (Edited)
Since starting to drive my Challenger again this year I’ve noticed a couple times, after a week or so+ sit, I get a tiny bit of oil burn right at start up. (55k Miles, has a catch can so rule that out). No noticeable loss of oil, I’m keeping my eye on it. Honestly I probably wouldn’t even have noticed it if I didn’t park in a garage.

Seems to be fairly classic valve seal indications (the same indications I had on my wife’s 5.7 Cherokee), anyone ever done these on a 392? From my research I believe the design is the same as the 5.7s. Should be able to pull the covers and replace with the heads still on.
 

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If it only does it after sitting a while, and it doesn't consume much when you check it, it's probably normal and nothing to worry about. But before doing anything, make sure your oil isn't overfull and that your dipstick is correct. There was a TSB for Grand Cherokee and Durango 5.7L with oil smoke on startup. They were being overfilled because the dipsticks were too short, so they read as if the oil was low if you put the recommended amount (6.6L) in. I haven't heard of that on the 392 but it's something to keep in mind.

If you're sure that's not the problem, then yes you should be able to change valve seals with the head still on. Use compressed air to hold the valves closed for that cylinder, use the valve spring tool for the Hemi, etc.
 

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Discussion Starter #3
I look at that too, haven’t ever heard that with the 392 but thanks for the info.

Appreciate the reply!
 

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Behavior/symptoms reads like oil in the intake. Catch can may not be 100% effective. If you want to know check the intake system for any signs of oil on the intake walls. My guess is you'll find some and that will explain the bit of oil smoke at engine start.

If the valve seals were leaking the chances are you'd see oil smoke during closed throttle coast down followed by getting back on the accelerator. This with the engine fully up to temperature. It can help too if you are driving away from a low sun. The sunlight helps make any smoke or other vapor in the exhaust more visible.
 

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Discussion Starter #5
Behavior/symptoms reads like oil in the intake. Catch can may not be 100% effective. If you want to know check the intake system for any signs of oil on the intake walls. My guess is you'll find some and that will explain the bit of oil smoke at engine start.

If the valve seals were leaking the chances are you'd see oil smoke during closed throttle coast down followed by getting back on the accelerator. This with the engine fully up to temperature. It can help too if you are driving away from a low sun. The sunlight helps make any smoke or other vapor in the exhaust more visible.
Thanks for the input, I’ll check the intake before I do anything.

I haven’t noticed any smoke at any time beyond start after sitting for a while.

Thanks again!
 

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That's really a sign of oil in the intake. Engine crankcase fumes are routed to the intake and these fumes of course contain oil vapor. The fumes have to make a sharp turn and in doing so the heavier oil vapor particles continue on and contact the intake wall and collect into liquid oil again. If you continue to run the engine the oil works its way into the combustion chambers and is burned with no real signs of this burning. IOWs, no smoking. But shut off the engine and the intake heats up -- heat soak -- and the oil drains down and collects on top of closed intake valve or flows past the open valve into the combustion chamber/cylinder.

Upon engine start one sees smoke.

Valve seals only leak when the engine is running and low pressure pulls oil down the valve stem/guide and into the combustion chamber.

Based on my experience with other engines that tend to smoke upon cold start my advice is to avoid short trips if possible. Do not run the oil too long. And short trips are really "hard" the oil contaminating it with among other things water. Water in the oil lowers its viscosity and makes it more likely to foam and form vapor. Do not overfill the engine. And use the right oil. The right oil will have a good detergent additive package to help prevent the formation of sludge - keeps this "stuff" in suspension so when the oil is drained this is removed along with the oil -- but also has an anti-foaming additive to prevent excessive frothing/foaming of the oil.

Smoking at cold start is quite common at the dealer. New (and used) cars get started often but seldom run very long. Just enough to move the cars about on the lot or showroom floor. (Dealer GM's believe that a reshuffle of the cars on floor and lot help promote sales so every once in a while all hands chip in to move cars about.)

Techs I've talked to about this smoking on cold start tell me when the engine smokes at cold start up as long as the smoking is brief, starts to decline as soon as it appears, the engine doesn't manifest any untoward behavior, and the CEL remains dark, they pay the smoking no further mind. And that's what I did and continue to do.
 
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