is there anyway this is anything but head gasket

237k miles on a 3.4l. bought this truck recently, when I checked it out it was raining heavily and I did not notice all the exhaust/thought it was condensation. The coolant was at a good level. I also had a shop check it out, they ran their computer on it and said everything looked good. Shortly afterwards I noticed how much exhaust it produces on cold starts and under load. I've driven it 1000 miles so far and coolant levels haven't dropped (oil hasn't either). I brought it to a second mechanic who said he saw no indication of head gasket problems. It runs well, aside from poor mpg (15.5 on rural highways and dirt roads in 4wd, my old 3.4 got about 18 under the same circumstances). What else could this be though. Video is of a cold start.

https://imgur.com/a/z0Z5kOA

 

Cold start if it goes away after warmed up and you are losing no fluids and none are mixing. The combusting of fossil fuels produces copious amounts of water as a natural byproduct of it. Ever watch a condensing [90%+] furnace run? It'll produce tons of moisture because it condenses back to water in the form of liquid due to the low exhaust temp. It was still present in standard furnaces but the temps were high enough for it not to condense out as actual liquid water.

 

It does this when it's warmed up and the motors under a little strain, like starting from stopped on a steep hill

 

If you're not seeing changes in coolant or oil levels, but you are noticing poor fuel economy, I'd be more inclined to think it might be running fat (too much fuel or not enough air intake). Hard tell from just this video, but that smoke appears to have a gray tinge to it, which would also align with a rich fuel mixture condition. Check the basics - air filter, spark plugs, fuel pressure. Use a scan tool to check fuel trim values and AF sensor readings to see if it's running rich. That's where I would start anyway.

 

What are the outside temps? Is it humid? Cats lighting off run exhaust temps up pretty high so maybe the cats are getting close to replacement along with the 02 sensor.

On a cold day in the north, most vehicles are putting out exhaust steam.

 

Ok thanks. It does have a cold air intake so maybe that's affecting it, don't know if that could be a factor.

It's not cold but definitely humid

 

You checking the coolant level by the overflow bottle or actually pulling the radiator cap and inspecting?

 

Both

 

Does it smell sweet? Does it smell like oil?

If neither of the above then another consideration is the vacuum valve for idle up on the power steering pump. Those can leak - when they do then ATF (PS fluid) get sucked into the manifold and burns off like this. Hard to find cause a lot of folks don't consider it typically. Pull the hoses and see if you spot any fluid in them.

*side benefit if it is ATF is that you're currently getting a free top end cleaner and I bet your piston tops look great

 

I’ve heard of similar symptoms being caused by a small crack in the head

 

Starting the engine and then revving it will definitely improve, keep doing that

just drive it an monitor fluids

 

pulling a few plugs and posting pix of them will def point in right direction

rusty---coolant in combustion chamber(HG/cracked head)
black/sooty---too much fuel(rich condition)
steam cleaned---poss what lightsoff saying ATF(a detergent) is in combustion chamber

 

Yeah monitor fluids and start reading the live engine data with an Bluetooth scanner. Maybe a compression test. If she’s running fine and maintaining fluids you probably don’t have a problem. Don’t overthink the exhaust characteristics. I’ve had plenty of times where I’m like that seems like a lot of smoke and my truck just drives and drives no problem.

 

So I pulled a couple plugs which do not look rusty to me. I also ran fuel trims a couple times. Unfortunately the app I used doesn't give averages, I think I might have to pay to get that, hopefully these aren't completely useless. The first is a short trip to town averaging 35 mph and the second is a drive mostly on a rural highway going 55/60 mph

 

Plugs look good

 

That higher speed long term looks funky to me. Anything over +/- 10 is worth investigating. Running poorly can definitely produce worse exhaust.

How does the front and rear o2 sensor look? I would maybe shift towards a fuel issue. If the head gasket was compromised you’d have some sort of fluid going somewhere.

 

That just looks like it's running rich.
Have you tried a stock air intake?