Smoke and plastic smell from engine bay - pass side

[Friday88]

Yesterday right as I pulled into my driveway after getting home from work, I noticed a small amount of white smoke coming out of the engine bay on the passenger side near the firewall. I immediately opened the hood, but saw nothing smoking. It smelled like hot plastic but there's no evidence that anything has been burning or hot in that particular area. I started it back up and let it run for awhile and the issue didn't repeat itself. I drove it to work today and everything has been fine.

Any idea what this could be? Back in November I was driving on the highway and had a coil pack die, which produced white smoke, but I got a check engine light with it and felt a loss of power. When replacing it I noticed the coil pack on cylinder 5 is still original, and if that one was smoking it may produce the smoke I saw. I just don't know why I wouldn't have a CEL at this point.

 

[BlackCat914]

Maybe you have a plastic shopping bag stuck to the exhaust.

 

[Scramble]

An oil leak from the valve covers onto the exhaust manifold can smell like burning plastic.

 

[mtbtim]

Like [MENTION=7105]Scramble[/MENTION] said above, I believe this is most likely a valve cover issue. Everyone of these 3.4 Liter V6's is going to need the valve cover gaskets replaced at some point. There's no getting around it unless you like to see an oily mess under your engine and everything else below like your steering rack. When the oil finds the very hot exhaust manifold, you'll get the smell you're experiencing.

If you're inclined to tackle your own repairs, the video below might help you out. If not, at least you know what's involved and you'll be better informed when you visit your favorite shop. Make sure you replace the cam plugs, reseal the half moons, and replace the spark plug tube seals while you're in there. This is also the opportune time to clean your throttle body, IAC, and your MAF sensor. Good luck!

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[Friday88]

An oil leak from the valve covers onto the exhaust manifold can smell like burning plastic.

Like [MENTION=7105]Scramble[/MENTION] said above, I believe this is most likely a valve cover issue. Everyone of these 3.4 Liter V6's is going to need the valve cover gaskets replaced at some point. There's no getting around it unless you like to see an oily mess under your engine and everything else below like your steering rack. When the oil finds the very hot exhaust manifold, you'll get the smell you're experiencing.

If you're inclined to tackle your own repairs, the video below might help you out. If not, at least you know what's involved and you'll be better informed when you visit your favorite shop. Make sure you replace the cam plugs, reseal the half moons, and replace the spark plug tube seals while you're in there. This is also the opportune time to clean your throttle body, IAC, and your MAF sensor. Good luck!

This is exactly what the problem is. I noticed oil on the driveway yesterday, and traced it up to the rear side of the valve cover. Tim I was actually just looking at your video. Hands down the best video tutorials on these trucks.

 

[atl_4runner]

Rattling Noise and Smoke coming from engine

I was driving my 99 4runner (hot day) and I started hearing a slapping noise from the engine (kind of like a belt slapping against the wall and it gets faster when I accelerate. About another mile down the road i felt the gas stutter a little. Kind of like when you run out of gas in a carbureted car. And another mile later when i started slowing down heavy white smoke started coming from under the hood. It sounds like a lawnmower now. Below is a video of the issue. I know it's not great but it'll give you an idea of what the engine sounds like and you can see where the smoke comes out of (looks like the passenger side cylinder head?). You guys have any ideas what the issue might be? Trying to brace myself for the repair cost.

https://youtu.be/PRHeDuax_dI

 

[curryT4R]

Glad you figured out the issue. Toyota engines, especially older V6 engines, are notorious for leaking valve covers. As Tim stated, its not a matter of IF, but a matter of WHEN, then valve cover gaskets will need to be replaced. Take your time and it should be a relatively simple job! Good luck.

 

[atl_4runner]

Sorry just joined the form. I'm not able to create a new post so I chose this post as it's the closest related to my issue. My issue is not resolved yet.

 

[Friday88]

Glad you figured out the issue. Toyota engines, especially older V6 engines, are notorious for leaking valve covers. As Tim stated, its not a matter of IF, but a matter of WHEN, then valve cover gaskets will need to be replaced. Take your time and it should be a relatively simple job! Good luck.

After replacing the gasket it's still dribbling from someplace lol. Not enough to leave spots on the ground, but the inside of the skidplates are nice and oily. I just keep an eye on the oil level and live with it.

 

[Friday88]

Sorry just joined the form. I'm not able to create a new post so I chose this post as it's the closest related to my issue. My issue is not resolved yet.

Film a video looking at the front. It looks like something is spraying out of the front for starters.

 

[octanejunkie]

After replacing the gasket it's still dribbling from someplace lol. Not enough to leave spots on the ground, but the inside of the skidplates are nice and oily. I just keep an eye on the oil level and live with it.

The rear cam seal is the usually the worst culprit. The Spark plug tube seals also, VCs will be oily and dusty, but not as much as the rear cam seals. The rubberized VGC itself hardens over time, as do the washers with rubber seats that clamp the valve covers. Tighten these down every few thousand miles or 1x a year will stave off a leak from the gasket itself.

If you are going to go through the trouble of replacing the VCG, do ALL the recommended parts and use the flexible gasket material (like permatex) as specified in the FSM (I would say "use common sense" but that gets people in trouble) and clean/detail the top end of the engine and plenum runners.

Budget a full day or weekend to not feel rushed

 

[Friday88]

The rear cam seal is the usually the worst culprit. The Spark plug tube seals also, VCs will be oily and dusty, but not as much as the rear cam seals. The rubberized VGC itself hardens over time, as do the washers with rubber seats that clamp the valve covers. Tighten these down every few thousand miles or 1x a year will stave off a leak from the gasket itself.

If you are going to go through the trouble of replacing the VCG, do ALL the recommended parts and use the flexible gasket material (like permatex) as specified in the FSM (I would say "use common sense" but that gets people in trouble) and clean/detail the top end of the engine and plenum runners.

Budget a full day or weekend to not feel rushed

Yeah I replaced everything according to a write up on this website. New gaskets, spark plug seals, pcv, rear cam seals and used RTV everywhere I read to. I think I may have gone too light with the RTV on the rear cam seals. I believe the leak is only from the rear on the drivers side though. I'll try tightening those bolts, but I'm not going to take it all apart again unless the leak gets bad.

 

[octanejunkie]

Yeah I replaced everything according to a write up on this website. New gaskets, spark plug seals, pcv, rear cam seals and used RTV everywhere I read to. I think I may have gone too light with the RTV on the rear cam seals. I believe the leak is only from the rear on the drivers side though. I'll try tightening those bolts, but I'm not going to take it all apart again unless the leak gets bad.

I did mine about 5K miles ago, it's still dry behind the heads. If yours is wet, oil, it's leaking