2016 TRD OR, Engine clanging, 1 oily spark plug

Hey guys maybe some experts weigh in on this.

2016 Tacoma TRD OR, access cab. 72000 total miles, 20,000 offroad miles.

On my trip a few days ago, this happened.

I drove 125 miles to a 4,000ft elevation lake. Outside temp was 9F.

Once there, I parked for 45 minutes. Then started the engine and drove 60 feet up a small incline. Tire spin, so i stopped and engaged 4wd.

Slowly drove the 60 feet up the minor incline and right away got a VERY strong oily fuelly smell from the engine. First time ever in 5 years getting a smell from the engine.

Got on the level grade, and the engine is LOUDLY knocking on the passenger side rear of engine.

I let it idle while I popped the hood open and made a video. Link at bottom. Note, my phone microphone really did not capture the sound very well. Bummed by that.

With the hood popped, the smell however was gone. Strange when the smell just 2 minutes earlier was so powerful.

The engine on passenger side rear was really clanging loud, which was quite shocking.

Note this truck always non stop makes the typical 3rd gen loud engine ticking sound on passenger rear side that many do. So this much extra noise was not good.

It was about 3 times louder than it has ever been, and this right after the big oily smell.

So I shut the engine off for 3 minutes. I turned it back on, and it had returned to normal with no excessive ticking noise or smells. I drove the 200km home, no issues. Strange…

Next day on spark plug inspection, I found that cylinder 5 plug (passenger side, rear end of engine), has some oil on the plug. The coil was mostly clean. See photo. The other 2 plugs on passenger were dry and clean. See photo of one of them. I did not check the driver side since all the noise was on passenger side.

These are new OEM plugs I put in at 55K miles. Torqued to 13 pounds. A lot of offroad, but done safely and never any crazy inclines or testing the vehicles limits. Not my style.

It is used strictly offroad to get me to remote fishing lakes. 80% of the time I need 4WD to access the lakes due to mud or gravel slippage or deactivated road washouts.

Note that the truck before this incident, and 2 days after has no engine performance or idle issues. Just this one time odd noisy and smelly incident, and the oil on that plug.

No oil leaks anywhere on or under the engine. Oil is changed every 5,000 miles, all OEM parts. No upgrades to engine, no tune, and it has driven perfect for the 5 years I have owned it. There was a few months period where it idled poorly, and cleaning the throttle body fixed that 100%. Air filter is clean, and I have a new mass airflow valve at 65000 miles. All vehicle fluids serviced prior to scheduled maintenance periods.

So two days later the truck still idles and drives perfect. It does seem though that the usual ticking sound is “maybe” a little louder now than before this incident. But nowhere near the shocking clanging sound it made after that oil smell.

That day I drove the 125 miles home, and yesterday I drove about 50 city miles, and no smells or performance or idle issues.

Any thoughts on that oil on cylinder 5 plug and why the strong oil smell followed by the loud clanging, that went away after it was shut off and restarted?

First pic is oily cyl 5 plug, then cyl 5 coil, one of the clean plugs, and inside of cyl 5 tube.

First 12 seconds of video is what to listen to. For comparison, I uploaded a video of what it sounds like now. Listen to that first 12 seconds also.

Again, the phone microphone did not pick up the loud noises that well.

Link to video with noise issue - https://www.youtube.com/watch?v=VSukZ8Tkscw

Link to video with normal sound - https://www.youtube.com/watch?v=mnhFFIoC3Bg

 

I've seen threads regarding inclines.

Apparently oil pools in the head then gets sucked into the vent/floods the engine essentially. Also oil starvation.

Typically you will see lots of smoke from the exhaust when it occurs.

People use catch cans to alleviate this but it can still be an issue.

There's a few threads around regarding this.

 

The “tick” in the videos sounds almost same to me but the camera probably didn’t capture the noise like you said.

BTW I moved to PG and loving it so far!

 

@Shveet is this similar to what yours did out in the Yukon?

 

Yeah, not the incline issue here. If it was, we would all have that issue from this tiny “hill”.

This was the spot, and I was going up this for maybe 60 seconds at 3mph. A 10 foot high hill over an 80 foot stretch. I am offroad every week, and normally some rough spots. This drive was on the flats most of the day, and the 3,000 ft elevation climb was over a 45 mile stretch.

Something else happened, not sure what.

 

Good for you on the PG move, no shortage of exploring up there.

BTW, I am going to pull that plug again today. It has been 3 days driving since, so I will see if it still getting oily.

 

So I drove it hard for 3 days and checked cyl 5 plug again, the one that had oil on it on that bush trip.

Nice and clean, no evidence of additonal oil on it.

Today I figured I might as well check the rear plug on the driver side. That plug was very clean. Truck idles perfect, no performance issues. No idea still on what caused the issue, but fine for now.

God I hate doing the plugs on the driver side. To start the plug back in, I use my special tool.

In our house chopsticks are for chinese food, and for changing spark plugs.

A 3 inch piece of rubber hose on the end of the chopstick. The plug tip inserts snug into that rubber tube.

A little tape around the chopstick and rubber tube to make sure they do not separate.

It makes it very easy to hand thread the plug in right up to almost hand tight. Then torque to 13 pounds. Much easier than even using a long magnet.

Now to wash up that chopstick and have dinner.

 

So I tried to recreate the issue I had several days ago, and today went offroad on some steep FSRs. Much, much steeper than the hill I was on when the issue happened.

No problem today. It ran very well, no smells and no odd noises. In 5 miles I climbed 1,800 feet with some very steep sections. Stopped a few times uphill, turned the engine off and let it sit for 10 - 15 minutes while getting some walking in. Did that several times and no issues. So, who knows what caused the oil smell and clanging issue from several days ago. A mystery.

 

I’d still replace your PCV valve as a preventative measure.

 

Yeah I hate to hear these kinds of glitches happening. A little unnerving if you are out in the back country regularly by yourself.

Also, concerning is any potential catastrophic failure.

I know these engines do some odd things now and again but why was plug #5 oily?

So, yeah. How did that oil get in there to oil the plug and cause that strong oily smell? Especially since you were not on a particularly steep incline.

Thinking out loud, Valve guide? PCV? Oil past the oil control ring? At this point, looks like it only happened once which is odd.

when you start it up cold in the mornings any hint of oil burning out the back exhaust?

I dunno, very odd indeed.

 

Bingo.

First video.


it's the vacuum pump on the back of the block, right behind cylinder 5. the TRD OR/ Pro Engines are significantly different than the TRD Sport/ SR5 ones, that is one of the main differences.

i had #5 "missfire" on me on the drive back. swapped plugs and coils around abut didn't notice any of them being oily in any way. granted it was -30c and a blizzard coming in when i started to swap them out in butt-fuck nowhere.


I've been driving like that for the last year, i've not had time to swap in the new ebay pump.

Edit: Photo of my plug in #5. mind you, plugs had 120,000km on them at that point


blizzard for lolz

 

drive side plugs suck ass.

get yourself two 10inch extensions or something and put a bar up against the pump behind the engine. you'll hear the "tick" clear as day. place it on cyl #5, and it'll be muddy.

 

Yeah, good point. I should have replaced the pcv when I had all that crap out of the way for that back plug on driver side. Gonna change that tomorrow.

 

Wow, your 120K km plugs look new, and cleaner than my 30K km plugs. My engine clearly runs hot.

 

No oil or smoking from the exhaust on startup, hot or cold.

 

I have seen a few posters mention the “vacuum pump.”

What vacuum pump are they talking about? Brakes? The Off Road and Pro models do not have a vacuum pump for the brakes as they are electro hydraulic. There is the vaccum pump near the gas tank for evap.

Are you referring to the high pressure fuel pump?

Just rummaged thru my tacoma paperwork, and found a warranty enhancement program mailer for the high pressure fuel pump. That might be the culprit.

The smell I got was oily mixed with a perfumy smell, in other words a gas smell mixed with it. That might also explain the louder than normal knocking ticking now.

Going to see if the dealer will cover the replacement under rhe warranty program.

Curious if they will even test it for pressure, or just say “does not smell now” or just replace it regardless.

Still going to do the pcv replacement tomorrow when part comes in.

 

Well, that was quick.

I called the dealer, explained what I noted in my original post here, and that the usual ticking is at times louder than normal now. They think high pressure fuel pump and are just going to change it out.

When I started the engine and went up that little hill, I had my heat on and my vents open (always open to draw in air for my sleepy brain…) and the oily sweet smell was immediate. The sweet smell I assume being the fuel.

The warranty papers note the smell happens on vehicle startup with heat on and vents open.

Yup, that was the case here. It was 4c that day at that elevation, and foggy and humid as heck on the drive up. I think that may be what contributed to it. For the past 4 months, 95% of my trips have been in very hot dry conditions with no rain or humidity. Maybe it took this weather and elevation to cause it to occur.

I think the oil on the one plug is a separate condition, and that may just be due to the pcv valve, or some other issue.

 

Good to hear it just may be that. Lets hope they get it re & re'd as soon as possible and that was all it was and nothing more.

Not sure about the vacuum pump on the back of the block tho and or the unusually oily plug.

 

That vacuum pump is meant for the crawl control stuff for the breaks. iirc it's mechanically driven to help provide more pressure to the electronic control stuff.

specifically i'm talking about this guy if you've not seen it.: https://static.nhtsa.gov/odi/rcl/2018/RCRIT-18V211-7735.pdf
there was a TSB for 2016s and 2017s but some early 2018s also got it but is far less common (iirc it was because they were meant to be 2017 trucks but spilled over past the new year)

TSB: https://www.tacomaworld.com/threads...-actual-issue-tbd.673992/page-3#post-23691514

Nother thread:
https://www.tacomaworld.com/threads...o-cam-problem-not-feeding-oil-to-pump.639263/

 

The vacuum pump is utilized because the engine makes practically no vacuum by itself. All models WITHOUT the electrically powered hydraulic brake booster have the vacuum pump.

Offroads and Pros with the hydraulic booster do not have a vacuum pump, they have a block off plate where the vacuum pump would normally go. All other models have the vacuum brake booster and as such need the vacuum pump.