I hadn't driven my '94 4runner since I moved and thought it could use 2 quarts of oil. It has a 3vze engine and the optimum oil level is 4 3/4 qts So I drove about 17 miles at 60 mph max(mostly 25-40 mph) before the oil light came on. Come to think of it, the engine was getting gradually more sluggish at the time. Smelled smoky, but nothing visible yet. Nursed it to a friends house letting it cool every time the light came back on. Here I drained the oil and put in the right amount. It was lightly smoking at this point. After a mile, thick oil smoke was billowing out of my pipe as thick as I could imagine. I've been told to drive it until the the smoke burns out of the heads, but after 12 more miles, the smoke is just as thick as ever. Help!

 

So you overfilled the engine by 2 quarts?

It took about 30 mins to clear out a buddies rig when we rolled it over, and his was a V6 as well. If the crankcase was way overfull, it could have pushed a ton of oil into the intake, which is now working on burning out.

Or, you could have sucked a valve or damaged a ring.

 

care to explain this term?

I've honestly never heard that one

 

If the smoke doesn't stop, how simple is it to replace that valve gasket?

 

I still don't understand whether you underfilled it or overfilled it? Did you JUST use 2 quarts? Did you add 2 quarts to a full crankcase?

Watch your mouth or I'm telling Wabbit.

Its when a valve looses its retaining C-clip/ breaks and the valve ends up in a cylinder bouncing around.

 

oooooh ok, got cha

how the hell could that happen


I would think that would cause a little more problems than just a little smoke...

 

Yep... you would hear that one.

 

Its when a valve looses its retaining C-clip/ breaks and the valve ends up in a cylinder bouncing around.[/QUOTE]


wouldn't that be "dropped a valve" not "sucked a valve" in either case it would suck

 

Just to clarify, too much oil. 6 1/2 quarts. So the initial thickest smoke stopped after another 10 minutes at idle, and it can be driven uner 2000 rpms without belching smoke. When you hit the throttle, it's the same thick oil smoke.

 

Dropped valve? how do I fix that?

 

thats now whats worng... unless your motor sounds like a mini jackhammer...

just drive it cautiously until the smoke clears out...

 

The only time I've heard the expression "suck a valve" was with reference to the old VW air-cooled upright fan engines. Sucking a valve in the #3 cylinder was a common failure mode. The oil cooler restricted air flow to the #3 cylinder. I think it was a heat/friction problem with valve stems rather than breaking retainers. I've never heard of one of these engines sucking a valve and still turning.

 

Note to self, "Check dipstick before adding oil."

 

With too much oil, the crankshaft would be dipping deep into the oil and whipping it to a froth. Air bubbles (like water) suck as a lubricant. You may have scored up the cylinder walls.

 

you really just flatly added oil to your truck without checking the level first?

bad move, but hopefully the lesson has been learned... hopefully

 

yeah, it runs like a mini jackhammer. How do I get in?

 

Less like a mini jackhammer and more like a really fast clock

 

In reference to desconcido's comment about VW engines... "sucking a valve" was usually due to hardened valve seats in the VW's softer metal heads. #3 is notoriously difficult to cool since its farthest from the fan and/or there is an oil cooler mounted in the airstream above it so the hot air from the cooler (hotter than the air to the other cylinders) was discharged on the cylinder and the head softened causing the valve spring to 'suck' the valve in to the head with the ultimate result being an inability to adjust the valves and eventual burning the valves and seats, leaks around the seats and overall destruction of head in the process. The problem was prevalent more-so on the type III and IV pancake engines than I and II engines, but nonetheless it gets the least effective cooling and the problem is compounded when the engine/body gasket fails allowing hot air from underneath to recirculate back to the engine bay and in the transporter models which already had poor airflow to the engine compartment.

More than likely, the overfilled crankcase has caused the oil scraper rings to become damaged and they are allowing excessive amounts of oil to remain on the cylinder walls and bypass the compression rings. With too much oil, the crank throws will actually come in contact with the oil in the pan and splash it up on to the cylinder walls below the pistons making it that much more difficult for the oil rings to do their job. They will compress away from the cylinder walls and than can cause the seal they have with the cylinder to become compromised and too much pressure against them can break them. At best, what deposits that were in the rings were flushed out and the rings just need to re-seat. At worst, the engine needs to come apart.
I wouldn't rely on a compression test to tell you what to do at this point.
Drain everything and take the engine through a break in procedure. If the rings just need to re-seat, it should clear itself up fairly quickly. If it doesn't, it's tear apart time.

Contemplating more about it... "...really fast clock." implies to me that it's possible that one or more wrist pins have been bent or damaged (probably, ironically, due to a lack of oil caused by the oil rings deposits restricting oil flow)... particularly if the engine idles reasonbly smooth- no misfiring / rough idling- that would imply the valves are all operating properly.

 

alright, I'm going in. It looks like it's gonna be a pain in the ass and I've never done that. What parts should I order and have on hand when I open up the engine to replace the valves?

 

like I said above, if it starts and idles fine, there's probably no issue with the valves.

so...