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Ok, I'll try to be in depth as possible with this post to get all the relevant info out there. I'm pretty mechanically inclined, but a old dog can always learn knew tricks.
I have an 08 Maxima SE with 153k. I bought it with 100k on it, 3rd owner from the Dealership (not sure of the entire maintenance history). I've owned the car for 2 1/2 years and have taken very good care of it. High Mileage oil at regular intervals.
About 2 weeks ago during a cold start after sitting all night (not cold weather location, I live in Florida and it's summertime right now), I noticed Grey/White Smoke coming from BOTH tail pipes. It wasn't a light smoke, heavier and lasted about 10 seconds. Checked my coolant and oil - nothing out of the ordinary.
My mechanic's initial thoughts on it were Valve Stem Seals.
And before I get the "you shouldn't drive the car" statements lol, it's not TOO concerning for me at this exact moment and yes I know the risks.
Tid bit of maintenance info - I had the Valve Covers and Gaskets replaced about 5 months ago due to a leak, along with getting the spark plugs replaced.
Well, due to only having 2 vehicles and my wife has the kids all day with the Van, I've had to drive the car short distances to work, being mindful not to overheat it. So, with that being said - I've been driving it and only smokes at first start of day along with if it sits for more than a couple of hours, and only for about 10 seconds.
I have NEVER had a problem with the car overheating since owning it. About 7 days ago, on the drive home from work - I stopped at a gas station to get a drink and left the car idling for about 3 minutes - came back and temp was registering between the half marker and 3/4 marker (mind you I pushed the car a little bit that night wanting to get home but nothing too crazy). This car has never ran over the half marker even in Florida Summers, always ever so slightly below. And it has not run anywhere near warm since that day - has stayed below half. for the last week.
I got it back on the road, and it cooled off obviously. Next morning, I checked the coolant level and it was about 1/2 gallon low, topped it off. Again, checked the oil and looked for leaks throughout the engine bay, nothing. I've slowly tried troubleshooting the problem over the last week (in hopes that it's not my worst fear - a blown head gasket, or worse warped/cracked head which I find unlikely or I would have major overheat problems). Here I am a week later and coolant and oil levels are still fine - haven't moved.
No bubbles in the radiator cap, but did a block test just in case - no exhaust gas traces. The liquid was good, checked it against the exhaust fumes and it worked.
Today I pulled the Engine plastic cover off - and low and behold there was a minimal amount of oil around the top of the Coil Pack (the one on the Front Bank next to the Oil Filler Neck). I pulled the Coil Pack - and the ever most slight amount of Oil on the inner diameter wall of the tube, no oil on the pack itself. Didn't have a spark plug socket to pull the plug and check the condition. I cleaned the tube and replaced the coil pack and will check it's condition in the morning after a night of sitting.
Mind you, I feel as though the Gas Mileage has dropped drastically on the car over the last month. I'm not how sure a busted head gasket would cause this, but I know fouled plugs will. My mechanic who changed the valve covers for me (because I didn't want to dive into it), immediately ruled out the coil pack possible leak because they were 'brand new' valve covers and gaskets. Obviously he doesn't want to fix something if he can say it isn't so. And I'm not even sure it's that causing the problem anyways, but I'm looking for any smoking gun at this point to rule out a head gasket. I've got a loaner Compression Tester from Advanced Auto Parts, but I didn't have time to do it today. I will try to get it done this weekend.
ANY THOUGHTS at all on this would be greatly appreciated. I love the car, but I might have to let it go. I can't be dropping a fortune in to it. If it does indeed end up being the head gaskets, I would most likely do all the work and spend roughly $500 bucks in parts to pretty much replace all the necessities on the top that you would typically want to change at head removal. Even then - I might consider getting rid of it before fixing it.
Do the compression test and a leak down test. That will tell you if there is an issue internally. Check any coolant tubed for pin holes.
Here's a great story that might put your mind at ease or make you think more. My old 3.5 Altima lost all the coolant from a bad hose. It was driven to the point where the gauge was pegged and running awful. It was driven further after a short cool down and the ECU said no more and shut off. After fixing the hose and adding coolant the engine was fine. Drive by wire systems are very smart. It makes me wonder how they could over heat to the point of head gasket failure.
Do the compression test and a leak down test. That will tell you if there is an issue internally. Check any coolant tubed for pin holes.
Here's a great story that might put your mind at ease or make you think more. My old 3.5 Altima lost all the coolant from a bad hose. It was driven to the point where the gauge was pegged and running awful. It was driven further after a short cool down and the ECU said no more and shut off. After fixing the hose and adding coolant the engine was fine. Drive by wire systems are very smart. It makes me wonder how they could over heat to the point of head gasket failure.
Thanks for the input. So, this morning just now I pulled the coil packs on the fwd bank (accessible of the 2) to check for oily conditions. The inside of the spark plug tubes were dry.
However, I noticed what 'looks' like oil sludge around the outside diameter of 2 of the 3 tubes in between the tubes and valve cover. It looks somewhat like grease - so not entirely sure if there is an o ring that goes right there that may have been lubed. I can not see very far in to tell anything else. Pics attached.
Nissan Mechanic suggest I change my PVC valve since it's cheap before going any further. Changed it (was loose, thread type) and quite oily. Hose is good. Valve rattled so not entirely sure if it's bad or not, but possibly being loose might have caused problems.
Pulled throttle body off. Quite oily and gunky and a small puddle of oil sitting in the bottom of the intake plenum. Air filter has some oil residue in it.
Cleaning it all up now and reassemble. Hopefully the PCV was the culprit. I'm sure that it's all clean now I most 'likely' will not get smoke on this 1st start attempt. Will give it a bit of time and get the TB and Intake again to check for oil. If there still is some I'm guessing I'm getting blowby from seals or piston rings?
Nearly 24 hours later. Car driven twice. After changing the valve and cleaning throttle body upon initial start, smoke. Drove 30 mins, sat 4 hours, start - no smoke. Car sat overnight for 12 hours, start - no smoke.
Either I got lucky, or it is seals/rings and will take a little time to show its face again since the valve replacement and cleaning...hoping for the 1st!
Having a similar smoke issue with my 3.5L after I:
- changed valve cover & gasket.
- new spark plugs & PCV valve.
- cleaned throttle body and intake plenum
Do you still have smoke issues? For me most noticeable when restarting after car sits for a few hours.
Note: I replaced valve cover & gasket in hope of fixing slow leak on right (passenger) side of engine that drips oil on my garage floor after sitting for a few days. The oil leak does not appear to have been fixed.
No, I havent had the smoke problem since then. But just like you, if i let her sit for a couple of days i will have a very very small puddle of oil on the driveway. It doesnt bother me to the point where i have to find out what it is, even though I've looked.
07-19-2018, 11:07 AM
