Jump to content

Due to a hardware failure on the hosts systems, all posts and messages created between May 26th and Jan 13th have been lost. Additionally, if you joined the NPORA Forums community during that time, you'll need to re-register. -NPORA Mod Team *Updated: 05/19/2022 12:15AM PST

Valve Cover Leak Hazard


Recommended Posts

I'm gearing up for a long trip and have been slowly getting things in order in terms of maintenance.  I made a recent post about my front drive-shaft and still have yet to get that sorted; of course I find another issue that seems to be more of a priority now.  My valve covers have been leaking for quite some time but within the past year I've noticed it getting worse.  I actually might be able to trace it back to when I switched from 10w-30 to a 5w-30 synthetic blend.  More recently it has increased in frequency.  Regardless, it's gotten to the point that I'm loosing about a quart every two weeks at best.  Now this is somewhat manageable but my biggest concern is that both banks are leaking on either exhaust manifold.  In a 24 hour period there isn't really much accumulation at all on the ground though when parked (few drops).  I can certainly smell the burning rubber stench after most drives.  This makes me think the system being pressurized when driving is what's pushing most of the oil out. 

 

So my main question is at what point does a valve cover leak of this nature become a fire hazard?  Does there have to be large quantities over a very short period of time, or is any burning smell a huge concern?  The shop I frequent knew about this and didn't sound too concerned over it.  In addition I definitely don't see any smoke coming from the engine bay or behind me in the rear view mirror.  I'm afraid that on a 1,500 mile drive though from everything getting hot, this would only be exacerbated.  Is it as simple as carrying a fire extinguisher but I shouldn't have to use it, or is it more of a toss up situation?

 

Lastly, I've looked into the fix and it seemingly is quite the endeavor.  Since my pathy has the plastic valve covers, everyone on here seems to have the consensus that if you're replacing the gasket, replace the valve covers as well (as we all know their tube seals are not serviceable).  There is also mention of warping at older age as another reason to replace.  That also doesn't include the "while you're in there" cost as well.  Sparkplugs, pcv, plethora of hoses and gaskets, knock sensor; I've heard people saying to not only replace the IACV gasket but also the IACV itself.  The problem is I just don't see myself keeping this vehicle much longer and this couldn't happen at a more inconvenient time of course.  My options it seems are pretty limited and I'm curious if anyone has tried those oil-stop leak snake oil products to any effect.  I'm also worried my pcv valve could be stuck in an almost closed position creating this newfound loss of oil.  Otherwise, any other fix besides replacing it is an exercise in futility.  It's funny, I find myself dreaming about having the older pre-facelift models with the 3.3 now probably because of their better reliability.  They tend to catch my eye more often on the road now as well.  Let me know of your experience and if I'm overlooking any other possibilities, thanks a bunch.  

Edited by cham
Link to comment
Share on other sites

If you don't see smoke, I wouldn't worry too much. That's not to say it couldn't catch fire--GM did a recall for their 3800s doing exactly that--but most things I've worked on were leaking some amount of oil onto the exhaust, and none of them came in because of engine fires. I can smell the leak in our snowplow, and it annoys me, but not enough that I've bothered trying to fix it again. My friend's Toyota was leaking bad enough that the oil was pooling between the head and the exhaust manifold gasket. That one was bad enough to smoke after driving, and bad enough that we replaced the gasket for fear of it catching fire.

 

I'm running high-mileage oil in my VG because it's cheap and why not. I haven't tracked my rear main leak to see if it's slowed any. Thicker oil might leak a little slower, but I wouldn't expect any flavor of goo-in-a-can to fix the gaskets if they're hard and cracked like mine were. If you can get to the valve cover fasteners, you might try snugging them up a little. IIRC there's also an oil cooler on the VQs that can leak, something else to check. I wouldn't assume it's a crankcase pressure issue just because it only leaks while running. The engine only pumps oil to the heads when it's running.

My dad had the PCV done on his '03 (chasing the quart/1000 miles oil consumption) and the guy said he managed it without pulling the intake, but it didn't sound like he had fun doing it. It didn't solve the oil consumption. I've heard various explanations for why some VQs guzzle oil, from the design of the PCV baffles to the power valve screws falling in and chewing stuff up to excessive bore taper. My dad's smoked on warm starts, but otherwise drove fine so long as he kept oil in it.

And, yeah, the IACV leaks coolant into the electronics and smokes the driver mosfet in the computer. Genius-level design at work there.


The VG has its own quirks/issues, but, yeah, I wasn't impressed with the VQ.

  • Like 1
Link to comment
Share on other sites

Thanks for the info, I thought as much.  Should I not expect a “low oil pressure” light anytime soon?  Is that pretty much only when the gaskets totally give way and provide no resistance?  
 

Would taking off just the upper plenum give me a larger amount of room to work with in getting at that PCV valve?  I am currently using high mileage oil as well.  I wonder if using a gasket swelling agent (stop-oil leak) in tandem with snugging the valve cover fasteners would be a good attempt.  I’ve heard though its a 50-50 chance at causing a worse leak or helping.
 

I have also heard about those sources of oil consumption as well.  The bore taper would make sense and I’ve also heard something about the cats as well.  I think if I remember correctly they are too close to the manifold; don’t quote me on that.  I think naturally due to the engine being new for those model years, the kinks no doubt had not been ironed out.  

 

Is that oil cooler seal just behind the steering rack above the front axle?  I think I’ve heard of that one before.

Link to comment
Share on other sites

My vq leaks considerably less and runs quieter with Rotella T4 15w40 for what that's worth. Valve cover gasket shouldn't affect oil pressure, the oil is just gravity draining back to the pan at that point. If its not smoking and your not constantly smelling burning oil I wouldn't worry about it on the trip. Always a good idea to have a fire extinguisher in the vehicle though! Lol

  • Like 2
Link to comment
Share on other sites

Posted (edited)
40 minutes ago, DesertKyle said:

My vq leaks considerably less and runs quieter with Rotella T4 15w40 for what that's worth. Valve cover gasket shouldn't affect oil pressure, the oil is just gravity draining back to the pan at that point. If its not smoking and your not constantly smelling burning oil I wouldn't worry about it on the trip. Always a good idea to have a fire extinguisher in the vehicle though! Lol

I'm a little apprehensive about changing the oil weight on an older vehicle that's worn with the factory weight all these years.  I do see that the manual actually does mention 10W-40 as a possible option if the ambient temp is over 0 degF.  Maybe something to try; should I be worried about causing any damage by switch weights at basically 200k?  Something to note is I do smell burning oil after almost every drive, even some shorter ones.  Never smell it in the cab though and I never see smoke either so I'm guessing its on its way to being a larger issue but not currently.   

Edited by cham
Link to comment
Share on other sites

Posted (edited)

I've ran most of my @!*%boxes on T4 over the years and they all had over 200k at the time and have never had an issue. This is just my experience though and everyone has a favorite oil. I also live in a very hot climate (southern Arizona).

 

As the motor wears and clearances increase it should help if anything. As long as the motor is spec'd for it, I wouldn't try it in something calling for 0w20 or the like. What's supposed to be bad is switching to synthetic oil on a high mileage engine as it can free up excess sludge and junk and tends to leak more. 

 

Depending on how bad your leaks are it might not make a drastic difference but it just might make your motor happier 😀👍

 

Edit to add I'm at 223k, truck had 196k when I got it

 

 

 

 

 

 

 

Edited by DesertKyle
Link to comment
Share on other sites

Posted (edited)

I can certainly understand the thinking behind increased tolerances and its ability to fill that clearance.  I guess because of the greater film thickness and shorter temporary shear the higher weight makes sense.  What you mention about synthetic oil kind of makes sense as I previously mentioned that I can trace the worsening of the gasket back to when I switched to a Valvoline Synthetic Blend 5w-30.  I was always told that its kind of a myth that synthetic fluids cause leaks but I think what is really going on is they expose leaks and seals being held together by sludge.  Regardless, if/when I switch to 10w-40, should I continue to use a synthetic blend or switch back to conventional would you think?  Also would there be any difference in leak rate between 5w-30 and 10w-30? Because it seems that most of the leak occurs during driving when things are already hot, 10w-30 would act the same or am I missing on a molecular level?

Edited by cham
Link to comment
Share on other sites

  • 1 month later...

Go ahead and buy new valve covers and save yourself the trouble of leaking spark plug tube seals. The stock seals are not really replaceable. I used some red aluminum valve covers from a 350z off Amazon and modified the valve covers to fit. These valve covers have east to replace tube seals. I started by plugging the breather tube on the left valve cover with quick steel, then drill and tap for a fitting on the top for the breather line. For the right side I cut the middle harness brace off the right side  and used a generic Dorman 3/8” 90* rubber pcv elbow for the pcv. Here is the link for the valve covers 

 

MITZONE Upgrade Aluminum Valve Covers Left and Right Compatible with 2003-2008 Nissan 350Z Infiniti FX35 G35 M35 VQ35DE 3.5L Part # 13264AM600 13264AM610 https://a.co/d/4ErRHj5 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

Welcome to NPORA Forums

 

Please register to gain full access to the forum.

Make sure you read the Forum Guidelines and don't forget to post a new intro in the New People Start Here! section, to say hi too everyone.

 

-NPORA

×
×
  • Create New...