lots of smoke when engine cold

I brought a 95 tacoma a couple of weeks ago and the truck was (and still is) running great but after I gave it an oil change it started smoking really bad when cold. the symptoms are. when truck first started it runs clean for about 10 or 15 seconds then starts smoking baddly. smokes for a good couple of minutes especially when the revs are dropping or the engine is under load (much worse if its idled for a few seconds or more). smoke also escaping around the exhaust manifold or at least in that area. mpg seems to have decreased although that could be because I have spent time scratching my head and whatching the truck smoke away! to me the smoke looks and smells like a combination of oil and fuel smoke. there is no water in the oil or fuel in the coolent (so I guess its not a head gasket???) I have a feeling I already know the answer (valve guides or rings) but im really hopeing somone may have another idea which may be an easier and quicker fix than that. Thanks in advance for any ideas you may have an for reading this far!

 

Hmmmmmm.

Did you change from mineral-based oil to synthetic (assuming you even knew what was in there). This could have knocked some old crap loose.

Did you accidentally overfill the oil?

Pull some plugs to see if they are fouling with oil?

 

I havnt pulled plugs yet, but I will later today. no idea what oil was in it to begin with but I filled it with castrol gtx high mileage 10w 30 ( I think its part synthetic?) and no, I didnt overfill. that was my first thought too but its just below the full line on the dip stick.

 

Hmmm, ya, your first intinct may be right...

http://www.toyotanation.com/forum/showthread.php?t=89857

If it didn't have synth in it before, the change could have cleaned out some nice, sludgy seals, then revealed the weak spots...

 

So, I took the truck in to a shop recomended to me by my father in law a couple of days ago and they put an additive in the oil for me. I also put a can of seafoam in my last tank of gas (after the smoke started) and today the smoke stopped. the mechanic told me that the additive would help to soften up any old seals and I guess he was right... Ill update again if there are any changes and when I know exactly what the additive was. So my only question now is if it was indeed the additive that stopped the smoke how long will this last? he told me that if it works I should make sure and have it added at every oil change but is it just going to breifly postpone the inevetable or could it actually "fix" the problem? I also had a thought that maybe the truck has the wrong dip stick in it and maybe I actually did overfill it, thus causeing the smoke... could any one tell me exactly how long my dip stick should be? Also a big thanks to scocar for your advice, it has been very much appreiciated

 

What the hell?? ^^^

 

He's on the dope.

 

makes perfect sense