[JoshCampbell]

BACKSTORY
OK so many of you already know much of the backstory on my Frontier. Except for maybe the part where my neighbor put $50 into it, before quitting and giving it back.

One thing I never mentioned was that it was also blowing white smoke out of the exhaust. It didn't start doing this until the day after I got so frustrated that I revved the hell out of it in the driveway, before realizing that 4 qts of freshly changed oil had suddenly vanished without a trace. It never overheated though.


FRONTIER SYMPTOMS:
*Thick white smoke from exhaust. But only after 2-3 minutes at idle and only thick until operating temp is reached, after that the exhaust is still present, but barely visible. It's actually light gray at first, then turns white.

*Excess liquid draining from exhaust. To be expected from increased steam. Taste like water. Can't describe the smell. Slight fuel smell, but could be normal. Never stuck my nose in the exhaust before lol. And I have no idea what the sweet smell of burned coolant smells like, but I'm guessing I'd know it if I smelled it.

*Idles like $hit once it reaches temp. However, this is inconclusive since it idled like $hit long before blowing white smoke.

*No loss of coolant, no bubbles at temp, and no exhaust gases present (Fluid remained dark blue).

*No overheating

*Dipstick and oil cap show only fresh clean oil (no white)

*All plugs looked good except #2. It was actually drenched in fuel, oil, and coolant. However, I had a slight coolant leak from a hose under the intake manifold above the #2 well, and I had been priming the fuel pump and messing with that injector, so this could all be unrelated. I did clean the plug and fixed the leaking coolant hose. Later I pulled #2 again and it looked good.

*Compression 160 psi across all 6 cylinders

THE REAL PROBLEM
OK, so those of you who know the history of this truck are probably thinking no doubt, blown head gasket. In fact, I'd be lying if I said I didn't agree with you 100%. Given the issues and abuse (from my ignorance) that this truck has sustained I'm surprised the engine hasn't fallen out of the frame. But.... here's where things get interesting. My 95 Pathfinder, with the same engine, and absolutely no problems EVER... is now doing the exact same thing not two months after the Frontier began doing it. The same thick white smoke after 2-3 minutes at idle, and only until it reaches temp. The main differences between the two vehicles are 1. I never messed with anything on the Pathfinder 2. It has 0 blown head gasket symptoms outside of the four or five minutes of thick white smoke. It starts, idles, and runs flawlessly. The MIL has come on recently, but I've also been restoring it. It's pre-OBD2, so I can't plug my reader to it. In any case the light came on long after the white smoke started. 99% positive it's unrelated.


THE QUESTION
If someone told me I blew a head gasket in the Frontier they'd get no argument from me. If someone told me the head gasket was suddenly going in the Pathfinder due to old age, despite showing no other signs, I might buy into that. But... you tell me that two vehicles, with the same engine (VG33E engines at that), both blew head gaskets within two months of each other, and with neither vehicle showing any conclusive symptoms of a bad HG aside from the temporary white exhaust... highly unlikely. It is possible, but statistically improbable. So the million dollar question is... what else, outside of gaskets and seals, can cause thick white exhaust? If we were only talking about the Frontier I would say it could be 100 different things causing it, like the PCV or AIC valve I put on it just before it started doing it, but with the untouched Pathfinder as well... it's got to be something simple. Like a sticking injector or somethings.


NOTE: I brought this question in here is because I inputted every permutation of my question that I could think of into Google and the only results I get back are The 8 signs of a blown head gasket. At some point you just get frustrated and say I know what the damn symptoms of a blown HG are, now tell me what else causes white smoke! I'm sure we've all been there more than once

Appreciate any insights you may have.


https://youtu.be/FeZm4Wo7SXw
Sorry about the video being at an angle. IPhone does strange things in the cold. I'll get a better one on here tomorrow.

 

[smj999smj]

If it's blue-ish white, then it's oil. That could be a head gasket, stuck open PCV valve or poor sealing piston rings. I once had a Datsun 510 that had a auto trans vacuum modulator diaphragm fail, causing transmission fluid to get sucked up into the engine; the thing killed every mosquito on the block! However, you probably don't have a vacuum modulator on your trans. Intake manifold gaskets leaking coolant have also been known to occur on VG engines.
White smoke...actually steam...on start-up is not an issue most of the time, especially in cold weather. Nor is water coming out of the exhaust. Water is a normal by-product of the combustion process of an efficiently running engine.

 

[JoshCampbell]

Sorry about that smj, started the thread on my mobile, but it was taking forever, so I moved to the PC to finish it.

Compression good across the board on both trucks.

I considered the manifold gasket allowing coolant into the cylinders, however the only way that could happen (far as I know) is if coolant trickles out and down into the spark plug well. If this is the case, then that's not it. Neither manifolds are leaking.

The PCV is definitely a contender for root cause, assuming a stuck PVC can produce white exhaust. I swap a new one on the Frontier and it began to smoke right after everything was reassembled. Never touched the PCV on the Pathfinder, but I did notice it was in the open position after shutting the engine off. My research says it should have been in closed position. It's OEM 1995

I knew someone would present the "white exhaust and condensation are normal in the cold" bit, which is why I hoped the video would be done before anyone saw this thread. It's not that.

One possibility I read about is bad/warped/leaking valve covers can cause excessive white exhaust. Mine aren't leaking, but if someone could confirm this through experience, then I'd be willing to give it a shot.

 

[JoshCampbell]

Oh, also wanted to add that I have ordered an HD borescope, which should be here on Saturday. I'll examine the carbon buildup on the piston heads, then know for sure if this is a HG issue or not.

 

[waxman]

You indicate no loss of coolant which seems counter to bad HG. Coolant in oil may not be visible in early stages. Try dripping some oil off the dipstick onto a hot exhaust manifold. If it sizzles there is some water/coolant.

 

[The other Sean]

What are the temps where you are right now?

Just to clarify, this is when the engine is started cold and for the most part clears up once the engine warms up?

How quickly does the "smoke" dissipate in to the air? To this MN guy, that looks a lot like steam / condensation than smoke.

You mentioned the truck runs poorly. I had an old GMC pickup with a janky carburetor and when it was cold out, it would kick up huge amounts of white exhaust (not smoke) until the engine warmed. I assumed this was due to the fuel / air mix being so far off. I've also noticed this about all cars up here in MN, they pump out more white when the engine is cold compared to once fully warmed up.

 

[JoshCampbell]

Just to clarify, this is when the engine is started cold and for the most part clears up once the engine warms up?

That's correct. It doesn't disappear as it typically would with cold weather exhaust. Plus, it was 70 degrees the other day and the smoke was even worse. It actually seems to be lessening more and more each day, which only adds to the oddness.


It's the Frontier that idled like crap, before and after the smoke issue began. The Pathfinder idles and runs perfectly, even though it now smokes exactly like the Frontier.

I'm currently living in San Antonio, but originally from Machias, Maine. Believe me when I say it's 100% not the typical cold weather smoke.

I have to be honest, I'm not sure why the typical cold weather startup smoke is even mentioned as a possibility in all the HG threads. I mean, let's be honest guys, we've all been driving for a long time, so we know what typical exhaust looks like in the cold lol



The main reason I brought this topic up is due to it's strange nature. Excess white exhaust on two vehicles, within two months of each other, but no other major HG symptoms. The goal here is merely to learn what else can cause excess white smoke. I'm troubleshooting it best I can, but I'm inexperienced. The day I joined this forum was the day I began learning to work on vehicles, so at this point I can only follow what I find online, and thus far I've found nothing in this regard. In essence, I'm like a newborn mechanic lol. Completely dependent on the nurturing and years of experience of others.

 

[The other Sean]

Just making sure I have full understanding. I've had a few vehicles stump me over what turned out to be a simple issue that was answered with one random question.

One more question, how much are these two vehicles being driven?

 

[JoshCampbell]

... One more question, how much are these two vehicles being driven?

The Pathfinder is a daily driver.

The Frontier has only seen the road a few times during the nine months I've had it (suffers from something, but I could never figure out what. Likely computer related). The Frontier began smoking after I removed the intake manifold (done several times before), cleaned it externally, installed new IAC, hoses and clamps, PCV, then reinstalled using the same gasket as the previous times. To be clear here... I mean that I reused the same manifold gasket each time. I purchased it about 7 months ago, and it looked like new, so kept using it. I started it up, everything was running perfectly, I took it for a 5 minute drive around the block until it began choking and stuttering as usual. I pulled in the driveway (frustrated as hell) and revved the **** out of it (maybe not as hard as I make it sound though). My hope was that revving it hard would break free whatever was clogged or causing the low idle and sputtering. Instead I believe I burned out a bearing (unconfirmed). 4 quarts of fresh oil had vanished without a trace, but that's another story. Any way, I believe the Frontier began blowing white smoke every time I started it after that. Of course it may have starter prior to the test drive. I honestly don't recall. In any case, the Frontier is its own story. Feel free to read through previous posts to get an understanding of its history. As I stated in my initial post, if this was just the Frontier, then I wouldn't be surprised if it was a blown HG. But the Pathfinder now doing the same thing two months later... just doesn't feel right.

I'm not naive enough to rule out a HG on both. It certainly is possible. But I've cried wolf so many times thinking my Pathfinder, motorcycle, lawn mower, etc.. was dead only to later figure out it was something as simple as a burned wire or lose spark plug that I now reserve judgment. My gut is telling me that something else is causing the white smoke. And since the engine in my Pathfinder is (far as I know) in perfect working condition, then solving this smoke issue on it means I can also solve it for the Frontier. Something in my gut is telling me that these two vehicles/engines have something in common that's causing this. (Made myself laugh as I thought... yeah, they both have a blown HG in common lol)

I certainly don't expect anyone to pinpoint the source of this issue for me over a thread. That's just not practical thinking. I was just hoping that some others had experienced thick white exhaust in the past, and that it turned out to be something other than a HG. More or less just looking for additional things to test. Does this make sense?


My current plan is to check the piston heads with the bore scope once it comes in. If one or more of the pistons look brand new and steam cleaned, then HG is confirmed. At that point I'll probably give Blue Devil a try. If they're all equally covered in carbon, then Hopefully the OEM PCV resolves the issue when it comes in. If that doesn't work I'll move on to replacing injectors. Final stand will be seals and gaskets.

 

[finallygotatruck]

If I recall correctly, You spent alot of time replacing alot of sensors and such on the top end....Then got pissed off and over revved the motor till it started knocking.


On THAT motor it could be anything from Intake seals to Cracked head. Start with a compression and leakdown test on the cooling system.


Leakdown will tell you alot.In fact, with the valve covers off and the spark plugs out it'll tell you what cylinder, you'll likely hear it.

I AM talking a leakdown on the cooling system btw....20 dollar radiator cap and some time.

 

[JoshCampbell]

If I recall correctly, You spent alot of time replacing alot of sensors and such on the top end....Then got pissed off and over revved the motor till it started knocking.

On THAT motor it could be anything from Intake seals to Cracked head. Start with a compression and leakdown test on the cooling system.

Leakdown will tell you alot.In fact, with the valve covers off and the spark plugs out it'll tell you what cylinder, you'll likely hear it.

I AM talking a leakdown on the cooling system btw....20 dollar radiator cap and some time.

I'm a little confused by your post. My concern is for the Pathfinder not the Frontier. The state of my Frontier's engine is well known at this point. My Pathfinder's engine/sensors (which are nearly identical to the Frontier's) are working perfectly, which is what makes the fact that it's beginning to show the same symptoms as the Frontier a real mystery.

Just think of the situation like this: You got two twin siblings with the same genetic code, but slightly different height, weight, etc.. Sibling 1, who already has a long history of health issues, contracts some unknown virus. This sibling begins to show symptoms that don't match any known viral diagnoses. Eventually sibling 1 dies. (or in my case, the Doctor grew frustrated with the constantly sick sibling and decided to bludgeon him into a coma in the driveway lol). Two months later sibling 2, who has never been sick a day in his life, now begins to exhibit the same irregular symptoms as his brother. The Doctors weren't surprised one bit when sibling 1 started to die, because he was never healthy to begin with, but now that sibling 2 is suddenly experiencing the same unexplainable symptoms... well now something just isn't right. Doctors dedicate all their resources to figuring out how to cure the healthy sibling first, and then if there's still time they'll take what they've learned and cure the sickly sibling that probably wouldn't survive anyway.


OK that's probably a horrible analogy, but hopefully it was at least interesting to read. I'm researching exactly how to perform a leak down test as we speak. I wasn't aware that you could do a leak down on the cooling system to reveal a blown HG, so I really appreciate that information. Will try to do it this weekend if AutoZone has the tool for rent.

 

[kevinjohnson3216]

I think losing the entire contents of your engine oil to the point where it's dry, without any external oil leaks, and the thick smoke pumping out at all times are related.

You said you weren't losing coolant and the exhaust gas test in the cooling system came out good

So the smoke must be oil smoke and you can't tell the difference between coolant smoke and oil smoke

If you're not losing coolant than it's not coolant smoke

The only two things that can make coolant smoke for a vg33 are a blown head gasket or a blown lower intake manifold gasket but you're not losing coolant in the first place

Oil smoke can come from piston rings, valve stem seals or pcv problems

Next step is a leak down test and it should give an obvious answer since you burned so much oil

 

[JoshCampbell]

I think you're right. I checked the piston heads with my new borescope. They all had the same amount of carbon buildup, and one had a couple droplets of fresh oil around the seams. Last night I set some lights up around the exhaust and it wasn't light gray, it was light blue. I'm guessing it's the ring. To make matters worse, there's an RPM dependent whine, which I pinpointed to the alternator. Of all the luck. It would happen right after I spend $1200 on body parts.

will throw a new alternator on so as to avoid embarrassing looks going down the road. We'll see how long it lasts after that.

 

[kevinjohnson3216]

I think you're right. I checked the piston heads with my new borescope. They all had the same amount of carbon buildup, and one had a couple droplets of fresh oil around the seams. Last night I set some lights up around the exhaust and it wasn't light gray, it was light blue. I'm guessing it's the ring. To make matters worse, there's an RPM dependent whine, which I pinpointed to the alternator. Of all the luck. It would happen right after I spend $1200 on body parts.

will throw a new alternator on so as to avoid embarrassing looks going down the road. We'll see how long it lasts after that.

Don't call the rings until you're sure, it seems that that's how you always screw up (low oil pressure = engine is toast = rev it up as hard as you can to kill it = later on come to find out low oil pressure is from no oil)

 

[JoshCampbell]

Haha... Oil level was first thing I checked. It's still full.

 

[kevinjohnson3216]

Haha... Oil level was first thing I checked. It's still full.

What I mean is don't jump the gun with the rings, might just need valve stem seals

 

[JoshCampbell]

Haha... Oil level was first thing I checked. It's still full.

What I mean is don't jump the gun with the rings, might just need valve stem seals

That's what I meant by seeing how long it lasts after the new alternator. I don't intend to do any engine work on it. between the Pathfinder and the Frontier I've invested nearly 13k and most of my time over the past year. It hurts to say it, but my coworkers were right, I could have had a brand new Titan almost paid off by now. Time to let them go

 

[JoshCampbell]

... I could have had a brand new Titan almost paid off by now. Time to let them go

Well, I was wrong (no surprises there). Just got back from a few hours of shopping for a shiny new Nissan and... Nope- Not driving that modern crap.

Buying an engine hoist and an engine stand when I go in to pick up my alternator tonight after work. According to its symptoms the Pathfinder does have leaky valve stem seals as Kevin suggested, so it will run for as long as I keep oil it. In the meantime, I'll start practicing on the Frontier's engine. Always nerve-racking the first time you do these things.

 

[kevinjohnson3216]

Im pretty sure With the right spring compressor you can do the valve stem seals with the head still on the engine and in the truck. Saw a video on YouTube of stevenyc or whatever doing it. He gave a link for the exact spring compressor to use

 

[JoshCampbell]

Im pretty sure With the right spring compressor you can do the valve stem seals with the head still on the engine and in the truck. Saw a video on YouTube of stevenyc or whatever doing it. He gave a link for the exact spring compressor to use

I saw that video as well. I got the hoist, the stand, a few recommended automotive air tools, two rolls of duct tape, and a box of Band-aids. Oh and a squishy stress ball. The Pathfinder still runs strong, while the Frontier does not, so safer to mess with that engine first, just in case. My hope is, if successful, that I'll have the knowledge to perform just about any automotive maintenance require once completed. New Valves, Pistons, rings, HG, Rod bearings, etc. is about as hard as it gets.

Going to be one hell of a learning curve, but well worth it in the end. And If I do mess it up beyond repair I'll have a salvage yard come and haul it off. Minus a center console