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White smoke while starting up Nissan NV2500

I bought a 2013 Nissan NV2500 V8 with 60,000 miles on it several months ago and after a few weeks I went to check the codes and got a P0303 which indicated a misfire on cylinder 3. I was advised to use seafoam in the gas tank to try and resolve the issue and I did that but I also decided to change the spark plugs to see if that would fix the issue, I changed them all and a few of them had ash deposits A little while after doing that I started to get white smoke on startup, at first I thought it was just a side effect of the seafoam but it kept doing so for a few weeks so I decided to do a block test to make sure the head gasket wasn’t the cause and the test showed it wasn’t. I also changed the PCV valves to make sure they aren’t the cause. I also did a wet/dry compression test which came out fine, there were differences between the wet and dry results but they seemed to above minimum. There is oil being burnt because and I periodically need to add some.

At this point I have no idea what’s causing the issue, the warranty expired on it so I want to see if I can fix it myself. Any advice would be appreciated, thanks

your dry readings seem to be OK

compression wet in 5/6/7 seem to be way too high, HOW MUCH oil you put there to get that high readings?

plugs 3 and lesser 1 have a lot of deposits, question would be “why?”

strangely, 1 is less compression wet when dry (?!?), seems to be some measurement error

having 3 with so much deposits, I would guess piton is also covered, but it is not much indicating that on dry compression read, or at least it is more or less in line with other cylinders

are you sure you made measurements right?

do you still get misfire codes after replacing spark plugs?

update: are you sure white smoke is not correlating to the temperature drop outside?

I put about a teaspoon of oil in each cylinder for the wet test, not sure if that was too much but that’s the recommendation I saw. I got a few minutes of white smoke on startup after the compression test so it might of been a little high.

I did end up replacing sparks 1 and 3 after the compression test because I inspected all plugs after removing them for the test and 1 and 3 had some ash deposits while all the other plugs were clean.

The white smoke happens no matter what the outside temperature is. I’m in Florida and I’ve experienced the smoke when the outside temperature was anywhere between 60 and 90 degrees.

well, after adding oil you would get some oily smoke, do not see any problem here

one spoon is not too much… so I can not explain why compression surged to 300+ in some cylinders, it is not diesel engine, is it? :slight_smile:

do you still have misfire codes or white smoke is the only thing you are concerned with?

to inspect insides of cylinders, you can get something like this:

tried that toy myself: quite amazing what you get for $10 nowadays

It’s a gasoline engine. There are no misfire codes (or any codes) or warning lights coming on, the white smoke/burning oil is the only issue.

I’ll give that camera a shot and check out those cylinders, thanks

my suspicion is that engine was badly worn and gets oil past the piston rings, which is very strange at such a low mileage, but you do not know the prior history on the car, do you?

with camera you would likely be able to confirm that by having a lot of deposits in the pistons and valves, your spark plugs are very suggestive in this direction

another theory would be with valve oil seals, but it is very unlikely at 4 years and 60K miles

sometimes it is possible to give engine a little bit of extra time before inevitable… piston rings might have “caked” with burned oil deposits and sit firmly in their grooves, so it is possible to use mild solvent in your regular oil to let them free. “marvel mystery oil” or “seafoam” added in proper proportion to the engine oil for few hundred miles might help, followed by oil change… but it is no guarantee as you can imagine

Unfortunately I don’t know the history of the vehicle but the CarFax didn’t indicate any major repairs.

I forgot to mention that I did try Marvel Mystery Oil (suggested to me previously) and it didn’t solve the issue either, I did do an oil change after the white smoke started in hopes of it helping but it didn’t clear the issue either.

Does the white smoke smell like burning oil, or coolant?

Adding any coolant?

It smells like burning oil. I didn’t have any issues with the coolant but I did run a block test and it returned negative so I’m assuming the head gasket it fine

so, looks more and more like worn piston rings :frowning:
get you piston tops examined with an endoscope, it will probably give us new set of clues

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