slight smoking upon start up.....

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3,771
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los angeles
Ever since i've used MMO and cd-2 and some B-12 in my oil,i get this slight oil burning when i first start up my engine when it's dead cold.What part of the engine causes this? I know it was probably caused by some cleaning.
 
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3,402
Location
Iowa
MMO is pretty runny. Might be making the oil seep past your valve guide seals a little bit while the engine sits. If so, it'll burn off when started and make a puff.
 

Kestas

Staff member
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13,820
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The Motor City
This is the typical symptom of worn valve guide seals. Sometimes it's the valve guide themselves that are worn. You may have cleaned what is called a "false seal", meaning the valve guides had a builup of deposits that were acting as a seal. Cleaning removed the deposits, freeing up the leak path.
 
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19,479
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Chicago Area
What is your concentration, and are you sure you are measuring it properly? I think you would get this slight burning on start up anyway - probably valve guides. Any chance this is the normal for almost all cars water vapor on start up?
 

daves66nova

Thread starter
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3,771
Location
los angeles
It didn't do this before i used the additives. This is for my 95 Camry 4-cyl. Any chance the seals can be changed out without taking off the head? I have since changed the oil to 15w40 and it still puffs.
 
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18,449
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East of IGO
 Originally Posted By: tom slick
Typically valve seals are the culprit of slight smoking during startup. I wouldn't worry about it right now.
+1
 
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your house
 Originally Posted By: daves66nova
Any chance the seals can be changed out without taking off the head?
No. The valves would drop onto the pistons.
 

JHZR2

Staff member
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44,817
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New Jersey
youve got all sorts of stuff in there that can flash, seep and move by, not to mention potentially phase separate...
 
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1,346
Location
Texas
 Originally Posted By: daves66nova
It didn't do this before i used the additives. This is for my 95 Camry 4-cyl. Any chance the seals can be changed out without taking off the head? I have since changed the oil to 15w40 and it still puffs.
Funny you ask. I've done it before without removing the head but you wont like how we did it. We pull the spark plugs and fed rope into the cylinder and then used a ratchet on the crank to make sure the valves were held against the rope which was held against the piston. I'm still amazed we didnt lose any valve keepers but we got all the seals swapped out and the motor went on its way.
 
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8,859
Location
Texas
 Originally Posted By: Fester
 Originally Posted By: daves66nova
Any chance the seals can be changed out without taking off the head?
No. The valves would drop onto the pistons.
So? One common procedure is to rotate the engine until cylinder number 1 is at TDC, do all the cylinder 1 valves, then rotate to #2, do all the cylinder 2 valves.... etc. With the piston at TDC, the valves can only drop slightly. The piston keeps them from falling all the way into the cylinder... which would be BAD. Its sometimes tricky getting the valve re-seated and the keepers back in place while the valve spring compressor is in the way, but it should be relatively easy on an OHC engine with light valve springs. An alternative method is to use compressed air to hold the valves shut on one cylinder at a time, but I don't like that method. It puts the piston at BDC, and if the air source should poop out in the middle of the job, the valves could indeed drop into the cylinder.
 
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Messages
194
Location
Colorado springs CO, USA
you can also use a compression test fitting to keep the cylinder pressurized with air to hold the valves up, we never removed the heads at the Toyota dealership I worked at for valve seals and I have a tool for popping the keepers out that is magnetic and will hold them when they come loose.
 
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3,402
Location
Iowa
I would just try it without the additives. See if it stops before you do all the seals. Whatever you tried to clean is probably clean by now and can go back to regular oil.
 
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489
Location
your house
Wow rope, rotate the cylinder, and compressed air. Never underestimate a determined mechanic, last time I had smoke was my old 302 1979 Mustang, a valve job fixed the seals and all, it was relatively painless, but to do as you describe would have been a quick job, if ever I require seals I will certainly try it.
 
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