lurnetsansop

Here's something I noticed while swapping a crank pulley -- the engine smokes a little from the front!

http://tinypic.com/r/e9zrq8/8 (video)

This happens only when the engine is nice and warm. There's no readily identifiable odor, except maybe "engine grime flavor", or maybe a hint of oil. Probably not gasoline exhaust, and probably not coolant (not sweet).

I'd guess this has been happening for at least a few days to a year -- I haven't watched the engine running hot for some time, and this is not visible with the hood down.

The engine, as you can see by the surrounding grime, does leak oil -- at least from the timing chain sensor or whatever that thing is on the chain cover. It's been like that for years and years though, and this smoke is relatively new.

So what do you folks think this could be? Is it dangerous to drive? Is this something common and harmless? I'm planning a 5 hour drive in a few days, is that a good idea?

max-nutcase

i would have to say u need valve cover gaskets!! as long as the oils full...drive it..just check it...but needs serious vc job!
man if they are in that bad of shape..your plug tubes must be really ugly!

lurnetsansop

Well, I did overheat this engine once before with a cracked radiator ( https://maxima.org/forums/4th-genera...-far-gone.html - It's a 170K engine now). Old username, same person. Head gasket passed the fluids and smells tests, so I assumed it okay. Could be the front valve cover gasket blew instead...

aackshun

iTrader: (3)

You are NOT going to see steam (aka white smoke) out the front of your motor unless you overheat the fck out of it. To the point where you warp the heads so bad you lose all compression.


(There was steam coming out of both heads before this photo was taken)

Road course an overheating VQ30 all day and you may be able to accomplish this too.

It's most likely leaking oil onto the manifolds, take care of basic maintenance and a nice lil washing of the engine bay.

LuminousX

change the Valve Cover gasket, looks like its well over due for a change

The Wizard

iTrader: (43)

You can clearly see that massive amounts of oil have leaked passed the valve cover gasket over time; it's all over the exhaust manifold. Replace the valve cover gasket and the spark plug tube seals too while you're at it.
And be sure to follow the torque specs and sequence in the FSM.

The rear valve cover is probably due as well.

D.Stillwell

Wow, what a gorgeous clean engine.

Listen to everyone and change the VC gaskets. That little bit of white smoke is simply from all the oil that's coated your manifold burning off, hence why it only does this when engine is hot.

lurnetsansop

Ok, thanks folks. I'll do the VC gasket and tube seals swap in a few weeks. I'll also replace the seal for that timing chain sensor that's definitely leaking. Is there some other maintenance worth doing while the valve cover is off?

Oh, and maybe i'll even clean out some of that grime...

max-nutcase

do the rear vc as well(w/tube seals)...and doing that clean your egr tube or u will prob have to do it soon anyway

CMax03

iTrader: (3)

If the front V/c looks like this,... just imagine what the rear V/c looks like! Does this car belong to Stevie Wonder or Jose Feliciano?

CS_AR

It's not a small job -- but properly done will bring great results and save you some money in the process. I think I have replaced 4 sets so far. Here's some tips below.

1) I try to get all gasket and seal mating surfaces squeaky clean like they were when the engine was being assembled at the factory.



2) Follow the Field Service Manual (FSM) recommendation for liquid sealant in the corners carefully. You will see where the original RTV sealer was installed at the factory. Trying to use more than the recommended amount will usually result in leaks later on.. Trust me on that one.. More is not always better when it comes to RTV. The last FelPro gasket kits I purchased came a tube of black RTV sealer.

Here's a link to the 4th gen How-To section for Upper Intake Manifold (UIM) removal that is important reading for when you are ready to replace the rear gaskets and seals.

https://maxima.org/forums/4th-genera...im-w-pics.html


Here's a video for the rear valve cover gasket job.

Note is is always good to watch more than one instructional video (if they exist) for a DIY repair job. I've noticed some videos omit/skip some of the more painful steps in a given DIY operation that others include.

http://www.youtube.com/watch?v=C_2GsFzAaMc

Here's a video for the front cover. Note: You do not need to remove the front timing cover as shown in the video.

http://www.youtube.com/watch?v=ZgCZlGUGxQM

M in KC

You are going to need an upper intake manifold gasket, throttle body gasket, "u" shaped coolant hose, egr tube gaskets, a tube of RTV, a case of carb and choke clear and several shop rags.

CS pretty much has it laid out for you. Take your time and do a good job the first time.

lowceez

Yeah, I just had my front and rear valve cover gaskets changed out about 6 months ago. I had all kinds of white smoke coming from the rear and the front. My 95 Maxima looked as if I was selling Bar-B-Q while stopped at the red lights. So not cool. I also had a leak on my stock y pipe as well. Now I'm running a fresh WS Y-pipe and fresh vc gaskets (front & rear). No more smoke for a while now.

lurnetsansop

Thanks for the advice, folks. I'll be doing this job in a week or two and will report back when I've begun and/or finished.

lurnetsansop

All finished! I replaced front and rear VC gaskets, cleaned the throttle body, replaced the (totally busted and rusted) knock sensor, and cleaned that horribly placed EGR tube.

Getting the bottom right nut off of the hacked bolt was a multi-day process of heat-gunning, loosener spray, and awkward angles. I ended up cutting through the nut with a rotary tool and just replacing it. The tube, by the way, was clogged all the way through.





The whole job was laborious in the rusty places, but otherwise pretty simple. I must say, though, that some parts of this engine are designed for looks rather than function. Specifically, the short pigtail coolant hose behind the UIM could have easily been in a more accessible location, but I suspect someone wanted a nicer-looking engine at the expense of a minute of sweat and swearing when re-seating the UIM.


The engine runs nicely now, and I see zero evidence of futher oil or smoke leaking through the valve cover seals.


Nice and clean.. Well, cleaner.

Thanks folks! Until next time...

JoshG

Very nice and glad to see you did it, how long did this job take you?

lurnetsansop

An hour or two to take off the TB, IACV, UIM, and such.
An intermittent hour or two to hack the EGR bolt, and then another hour to break that nut, which i eventually just dremeled through.
30 mins to clean the EGR tube, gasket surfaces, place gaskets and liquid rubber and such.
An hour to replace the knock sensor -- I can't reach it with a tool from the side, so I took off the fuel injectors and lifted the lower intake manifold to reach it. Also replaced the (brittle) fuel line hose going to the injector lines.

Another hour to replace valve covers, UIM, and so on. I had to redo the UIM because I didn't tighten the pigtail coolant hose way in the back near the EGR tube. Also replaced a few brittle hoses.

I reused the EGR gaskets and made ones out of gasket paper for the TB and IACV.
Total time spent: 5-6.5 hours, stretched over a few days.

The Wizard

iTrader: (43)

Good job

CS_AR

Congratulations!

DBear

I"m surprised--when I did my EGR tube, it took me about 10 minutes to saw the end of the bolt off. I just used a hacksaw blade, and pointed the teeth toward the rear of the engine compartment, IIRC. Using gloves, that gave me plenty of force on it, and it went easily.

max ride 41

iTrader: (4)

now, please clean the leaves out of the cowl and shine up the engine and surrounding area's and you'll want to pop the hood and stare at your vq!!!