More and more often my 93 jimmy has been puffing out some smoke when I
start it up. From what I know, it the valvestem seals. Would thicker oil
help at all? Also, what happens when the valve stem seals break? Would it
I doubt that thicker oil will help you much.
There will be no other damage to the car if the
valve seals happen to "break". In most case, they
simply get hard with age and become very brittle.
They don't seal well when they are brittle. The only
real fix is to replace the valve seals. GM has a kit
available with the original o-ring seals, and updated
umbrella seals for both the intake and exhaust valves.
Thicker oil may help a little but personally I would not even worry
about it until it gets to the point that you are adding a quart of oil
every 800 or so. It is lots a lot more troublesome than it really is.
Thicker oil won't help ya. That would potentially cause damage to your
engine depending on what climate you live in. 93 Jimmy, don't worry about
it. They can not cause any damage to your engine. May get a little worse but
don't sweat em if you can deal with a little smoke. Fixing valve seals can
lead to a whole lot more. First you realize that valve guides are wore so
you pull the heads. Then you see what a ridge on the top of the cylinder so
you cut them down to re ring. Then you drop the pan and find bearing wear.
Damn now its time for a full rebuild. At least that is how it works for me
usually. I can't seem to change a plug wire without a overhaul :).
Not really, while valve seals can cause some oil consumption problems
that are not critical, they are easy to replace without removing heads
and there failure while the rest of the engine is in good shap is not
that uncommon either. I would not wory about them untill your oil
consumption exceeds a quart ever 800 to 1000 miles or so.
Depending on how hard you drive and how bad they are leaking will determine
any damage. A fuel oil mix burns at a hotter temp than just fuel. The more
oil the hotter exhaust gas. I used to just put up with the smoke but than
one day towing my trailer I burned an exhaust valve. If you are keeping the
vehicle I would just replace the seals, it really isn't that big a job. You
don't need to remove the heads.
Since you are the expert, and so certain I had other problems, how many
burnt valves have you seen and what do you think caused them? :-)
I know retarded timing will cause hot exhaust but my timing was right on.
I know oil/fuel burns hotter than fuel.
I know running lean can also cause hot exhaust, (this may be the most common
cause) but the valve that burnt was on the cylinder with the failed seal.
I can only conclude the seal failure had something to do with the valve
I have seen a lot in my life, more than I can count. As to the causes it
can be anything from to little valve lash on a mechanical cam or a worn
lifter lobe the does not let valve fully contact seat properly or let it
spend enough time in the seat to propelry cool the valve head. (a very
important aspect of operation) A lean mixed can also "fry" the exhasut
valves under the right conditions as can badly worn valve guides that do
not seat the valve correctly all the time. The number one failure today
I would have to say is motor knock or detination because of some peoples
continued insistance to use the lowest octane and cheapest fuel they can
find in modern closed loop higher comprssion engines. When it occurs
enough with enough intesity, it can case the valves to vibrate in the
seats and during this virbration leakage occurs and over time errosion
of the surfaces sets in and once errosion hits a certain level it
accelerates and makes itself known. BTW I studied IC engine design and
theories in the 70's while persuing a engineering degree and while the
methods of fuel and emmisons control have changed since then, the basic
theories and thermodynamic principles that a engine operates on have not
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