About 3 months ago I bought a 96 sr5 4runner w/3.4 with 190k on it for a decent price of $2200. The only service history known was the valve cover gaskets were just replaced. It ran but I would not call it smooth. When I got it home and preformed a better inspection I found some oil in the air box. So far I have Sea Foamed the engine, changed the oil twice (it was very dirty when I got it), replaced spark plugs with the proper ones, Fixed an oil leak, added an external tranny cooler, Replaced the air filter, Cleaned the TB, changed the coolant, changed the PCV valve, and had the front end aligned. After all that it ran much better but it sounds like the valves need adjusting. A guy who works for Toyoda that I bought some rims from of craigslist listened to it and says he would not worry too much about it. My wife and son drove it for about 600 miles and no smoke or oil in the airbox. My son and I towed my golf cart (about #1000) about 90 miles. It towed fine but if you touched the gas it would downshift so it was running 2800+ rpm a lot of the time. It had plenty of power and could not even tell it was there. At the end of the day we were going home and when I started it there was a lot of smoke for about 2 seconds then no more smoke. We drove home and stopped for about 10 min on the way home and when I started it no smoke. We got home fine and parked. The next day when it was stared it smoked for a few seconds again. I checked and we had a few drops of new oil in the air box. After that it can sit overnight but it doesn’t smoke or use oil. It has been two weeks and about 500 miles with no smoke. I still get a couple drops but nothing like before.
Any ideas what caused this?
Thanks

 

Here's a thread with some information that might help you. The end culprit for this person ended up being a very sludgy engine. I know you've changed the oil twice and seafoamed it, so I'm thinking if it is sludge related that the PCV valve is clogged because of the seafoaming/loosening of the sludge or despite the seafoaming and oil changes, the sludge remains and is causing some issues.

I know you've replaced the PCV valve, but give it a look again and check out the hose too. If the PCV hose is clogged, the same mess can happen.

https://www.yotatech.com/forums/f2/o...e-tube-212773/

If it's only smoking at startup, that could be the valve seals.

http://www.toyota-4runner.org/3rd-ge...ir-filter.html

Here's another suggestion, since you said the valve cover gaskets have been done recently:

"One other thing to check, I saw this on a mazda v6 once, someone had changed the valve cover gaskets and on one of the valve covers the top part of the gasket fell out creating a huge vacum leak into the valve cover which sucked oil through a pcv hose into the intake. On the 4runner, drivers side valve cover there is a hose at the rear that comes up to the intake, runs through a metal pipe then through another hose that goes into the intake tube near the throttle body, firewall side; you might check that hose for oil."

I'm not a mechanic, so I'm really taking what other, more knowledgeable people have said in other threads. Give those a look and maybe they'll help you out.

 

The thing that gets me is it only smoked after the car sat after towing not all the time. The the oil in the air box has been like one or two drops after 500 to 600 miles normal driving but much more during 180 miles of towing.

Thanks for the links

 

Just brainstorming here, but I wonder if that could be because, like you said, when you were towing you were running higher RPMs the whole way. Higher rpms would mean higher oil pressure. That seems to make sense as to why there'd be worse of an oil problem after the towing.

It could be that as it was running and the oil was up to temp and a little less viscous, it gathered in your airbox/intake. Later, after it sat and the oil cooled off when you went to start it you got smoke as it burned that off.

It seems like the culprit has been PCV related for most people that have this issue. It's such a cheap thing too, I'd be inclined to go back to that and check the hose and maybe even try another. I'm just thinking if the oil was that bad like you said when you got it from the P/O, your seafoaming/oil changes could be kicking around sludge and it's just a matter of time until the PCV is all clogged one way or the other.

Anyway, hopefully someone with better knowledge will comment back and shed some light if they can.

Also, I take it in your first post, you meant 190K? If you decide you're fed up and want to throw the rig away, let me know, haha!

Good luck!

 

I think it is a sludge issue... Not much I can do about that anyway. It mostly going to be for my son to drive so I don't think I will tow with it much. The hose is good as that is the hose I sea foamed it with. I am running mobile 1 synthetic in it now. The first oil change I just ran dino when I sea foamed it and ran it 200 miles with the sea foam in the oil. It got dark quick. I changed that out with synthetic and the color is a nice amber after about 900 miles.

It can stay in Rock Hill for now but later i may trade for some shrimp and grits.

 

Yeah, not much you can do about it unless you want to pull the valve covers off an manually scrape some of it out. If it's running okay though and only intermittently smoking, then just leave it. That's not a bad deal for around $2K and not unexpected if you don't have any maintenance information from the P/O. I'd run some seafoam on the next couple of oil changes, maybe less of an interval than recommended and see how it goes from there. Good luck!

 

Hello from Columbia, SC (moved here in October).

If it were me, I'd add a quart of Marvel Mystery Oil at the next oil change.

 

I added some MMO this weekend so we will see.

I am 99% sure the engine is sludged up but If I keep the oil changed every 3k and use synthetic. Will it get any worse? Once it is sludged does that mean it is going to take a crap at any time?

 

amsoil sells some good sludge remover stuff

 

Here's some good reading on the subject of sludge and old dirty engines. Hope it helps. Good luck with the rig.

https://www.yotatech.com/forums/f2/o...ttacks-167704/

https://www.yotatech.com/forums/f2/s...y-work-243376/