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Smoke at Startup - Valve Guides???

PWagon

PWagon

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Hey guys! I have a 86 K5 (305 c.i.) with 186,000 miles that smokes like the Marlboro Man at startup. It does not use that much oil at all. The engine idles great and smooth, and there is no engine noise (no pings/ no knocks). I suspect the valve guides are shot, but I'm unsure how to tell without tearing into it. Does anyone have any ideas on how to tell before I go taking things apart? :confused:
 
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There's no visible use of oil on the dipstick. It's obviously burning some oil at start up though.
 
Guides and seals are usually the first to go. However with that many miles, it would be best to have a full rebuild if you're going to bother getting into it.
 
Similar question, what about a puff of blue smoke at 1st startup after the vehicle has been sitting over night? 88 crewcab 350TBI 46,xxx miles
 
Blue smoke at start up or heavy throttle is either guides or seals, blue smoke all the time is rings.
 
4X4HIGH said:
Blue smoke at start up or heavy throttle is either guides or seals, blue smoke all the time is rings.
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Sorry for the nOObish question here fellas but what seals would you be speaking of? Just trying to learn a little every day.:o
 
There refering to the valve guide seals. if you were to remove a valve cover and look at the top of the valve guide thru the valve spring and where it protrudes above the head you would see one on each valve guide. To bad a $.50 cent part can make for so many ugly problems.
 
apache said:
There refering to the valve guide seals. if you were to remove a valve cover and look at the top of the valve guide thru the valve spring and where it protrudes above the head you would see one on each valve guide. To bad a $.50 cent part can make for so many ugly problems.
Click to expand...

That isn't always true, the early engines only used an O-ring seal in a groove just below the keepers which gets sandwhiched by the retainer.
 
We're talking about the seals/guides around the valves that are supposed to prevent engine oil from leaking into the combustion chamber. Over time they age and crack allowing oil to seep through. When the engine starts, the oil is burned off and smoke appears at the tail pipe.
 
its a common problem ..... and not too hard to fix. could be worse and you could have a dohc motor and have to do this job...... i speak from experince
 
I get "white-ish" smoke at start-up, then it goes away. I'm guessing the head gaskets are leaking allowing some coolant to get in. This is vaporizing in the cylinder and coming out the exhaust. What do you think?

Also, if its the valve guide seals how hard are they to replace? Do I need to take the engine out or just the valve cover off?
 
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