NEED HELP Purge Valve Leak and Engine Grounds

Dadwagon

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May 21, 2020
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As seen on the left of my 4.2 block today, for your consideration.

Is this the purge valve? If it's that covered in oil, does it signal the valve is failed or soon to fail? If it's not throwing a CEL at this time, does it make sense to replace at this time?
And if the valve was leaking some oil, would that oil hitting the lower left ground wire be enough to make that a "bad ground" and signal electrical equipment to fail?
 

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Reprise

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(on edit, now that I see the picture on my laptop, and not on my phone) :

What's on there is accumulated oily grease, from an external source.
The internals s/b OK, especially if you have no codes, and those fasteners are pretty secure, by design.
Clean the area, look for any potential cracks in the valve. If none, move on to other things that may require attention.

_______________________________________________________________________________________________________
That looks similar to the ones in my V8 trucks, so I'll take a guess and say 'yes', that's your purge solenoid. There should be no oil *inside* it, as it's an evaporative emissions component (e.g.; fuel vapor recovery).

If there's oil *on* it, it probably came from somewhere else. Maybe a valve cover, etc.?

If there's oil *in* it, check the evap tube, which should be the solo one on the LH side in your pic. And check the other end, where it terminates (engine end). I'd wait until you got a code to replace it, unless you've got an emissions test or something coming up.

PS: If the clips on both ends are like mine, you squeeze on opposite ends to release them from the pipe (which is plastic and can break, so no super rough handling. Leave the clip in the pipe - it clicks over the orifice, when you put it back on.

As far as wiring... oil can affect it, but it's nowhere near as catastrophic as water, etc. Your transmission has a wiring harness in the pan area, and it's submerged in a petroleum-based fluid 24/7, for example.

I'd give it a good spray with some brake cleaner and reattach, myself.
 
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mrrsm

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There are (3) Possible Sources for this Condition:

(1) If that Material is VERY Sticky... A Ruptured Casing-Liner on the "Rubber Ball" of the Driver's Side Motor Mount can sometimes squeeze out and physically eject the Internal "Semi-Liquid Gel" and manage to decorate either the Engine Block on that side... or the Inner Fender Well on the other side of the "Rubber Ball" if the rupture occurs there.

(2) During each Start-Up, the EVAP Purge Valve Mounted on the Left Side of the Engine Block serves to open and allow the accumulated Fuel Vapors to get drawn in from the Charcoal Canister and thence into the Throttle Body-Intake Manifold. If the Connector of the Vacuum Line Connector on that Valve is damaged, then the offending Gas Vapors can collect and "Gum Up" that locale over time if open left open to the Atmosphere.

(3) As born out by VISIBLE Evidence present in your Attached Image... the Low Torque Trapped Fasteners (...NEVER use more than 87-89 Inch Pounds to Re-Tighten these...) holding the Intake Manifold to the Engine Head will gradually loosen up as the IM Rocks Back and forth like a Pendulum during Normal Driving Operations in between the Weight of the Throttle Body ..versus the Weight of the PCM Bolted diagonally on its opposite side. 10-15 years of these Gyrations are usually enough to "Do these Gaskets in..."

Over the years, the amount of this Oil that can collect inside of the IM can be quite SUBSTANTIAL and once the Engine Head Cools down after hundreds of repeat Thermal Cycling, those flattened, worn and loose "Figure 8" "O" Ring-Style Gaskets will eventually collapse. This event will allow the Oil laying along the inside of the IM Lower Flange Line to Leak Out under Gravity. In time, anything that gets between those Drops of Oil and the Ground.. .will eventually become covered with that Old Oil.

A Word of Caution:

For those who think they can "Just Tighten Down the IM Bolts against the Gasket(s)..." The Trapped Fasteners supporting the LL8 IM are NOT Fault Tolerant. The reason this will become IMPOSSIBLE is because the Fasteners are fitted with Protruding Bolt Shanks, just above their foreshortened Thread Lines that will STOP DEAD upon Direct Contact with the Flat Surface of the Intake Ports on the Aluminum Engine Head. If you proceed with attempting to Tighten them down even further... The Threaded Portions will Snap Clean Off ***

When the Gaskets leak too much... Replacement may become necessary... and REALLY should be avoided if possible, as this Task is One Supreme PITA.

EDIT:

*** The Coil On Plug (COP) Fasteners are designed in the same manner as the ones used to hold the GM Vortec 4200 LL8 Engine Valve Cover in place. If TOO Much Tightening force is applied above 89 Inch Pounds, those COP Hold Down Fasteners will likewise just Snap Right Off. But do not despair... I've penned a "How To" that will Rescue this situation Perfectly using a Specific Time-Sert Repair Kit. Visit this Link for more information as needed:


 
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Dadwagon

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When I removed and cleaned the throttle body a few weeks ago, the rubber breather pieces had oil on them. And the bolt above the purge valve on the upper left appears to be for the intake manifold. Looks like a tear down of the intake manifold and gasket replacement might be in the near future.
 

mrrsm

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Before you have to do this work, allow me the chance to Inform... and Forearm you with an EVEN DOZEN SUGGESTIONS that will make Your life a bit EZR while You are trying to Kill Three R&R Birds with ONE STONE:

(1) MOST of the Access to the Intake Manifold Fasteners on the IM Flange Line will have to be done THROUGH THE BOTTOM OF THE DRIVER'S SIDE WHEEL WELL.

(2) The 2nd Hardest Part will be trying to Access the Last Few Fasteners hiding along the Firewall.

(3) The VERY Hardest Part will be the necessity of Removing this PITA Harness Bundle Bracket:

BRACKET1.jpgBRACKET2.jpg

(4) Take Plenty of Pictures of Exactly How the Wiring Harnesses are Held In Place around this Complicated Bracket FIRST. Try not to Break any Retention Clips when getting that Bracket Out.

(5) Obtain a Brand New Valve Cover Gasket Set and R&R THOSE at the SAME TIME you are working to Replace the Intake Manifold Gaskets:

https://www.rockauto.com/en/catalog...2l+l6,1424281,engine,valve+cover+gasket,10710

MAHLETBVALVECOVERGASKETSET.jpg

(6) Obtain THIS Tool, ...or a Tool Set like THIS:

https://www.amazon.com/dp/B0734VKNYK/?tag=gmtnation-20

PLASTICLIPSTOOL1.jpgPLASTICLIPSTOOL2.jpgPLASTICLIPSTOOL3.jpg

(7) Obtain the Correct (Non-Bogus) ACDelco Spark Plugs and Change Them while it is very convenient to do so:

https://www.rockauto.com/en/catalog...azer,4.2l+l6,1424281,ignition,spark+plug,7212

ACDELCOIRIDIUM.jpg

(8) Obtain Scott “BLUE” Shop Towels to wipe out the (6) Intake Ports of Old Oily Grime.

(9) Avoid allowing ANY Oily GRIT from dropping onto the Intake Ports and Valves.

(10) Plan on being Tied Up with doing this R&R for at LEAST Four Hours and use ACDelco for the Intake Manifold Gaskets and the Full Gasket Set for the Valve Cover from MAHLE:

https://www.rockauto.com/en/catalog...l6,1424281,engine,intake+manifold+gasket,5424

ACDELCOINTAKEMANIFOLDGASKETS1.jpg

(11) Installing ALL of these Gaskets requires Attention to the Details here. You cannot simply "Lay On The Gaskets" as they are designed with an "I"Beam Slot Configuration. This shape requires that they Must ALL be WORKED INTO PLACE PROPERLY ...or they will NOT SEAL.

(12) Take Your Time and Be Patient. Getting this Right The FIRST Time means NOT Having to give these Gaskets a Second Thought ...once all of this Work is DONE.

I've created a PDF of this Information for the future reference by other Members:
 

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Dadwagon

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Ooof. My last vehicle was a Saturn s series that I replaced valve cover and gasket on. That was less than a year ago. Not looking forward to this.
 

mrrsm

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After draining out as much Old Engine Oil from inside of these things as possible,
It will greatly improve the handling and preparation of the Engine Head Valve Cover, Intake Manifold and Air Intake Plenum if you can Spray them all down... Inside and Out with "Purple Power" De-Greaser to dissolve away all of the accumulation of residual Old Engine Oil from inside of all Three components.

After letting them soak for a while, douse off the "Purple Power" De-Greaser in the Kitchen Sink using Hot Water, or via a Garden Hose in the yard. Then use a Nozzle with Compressed Air to blow out the residual water. Place them all out in the Sun on a piece of cardboard long enough to allow them to completely dry out.

Installing the myriad Special "O" Ring Style Gaskets on thoroughly cleaned surfaces and when handling all three items for their re-installation will make things much more manageable and remove contamination of the "O" Ring "I" Grooves.

"Purple Power" is Non-Toxic and Bio-Degradeable with almost no odor and NO VOCs ... so the stuff will do no harm if used indoors in your Oven, Kitchen Sink or Bath Tub.


 

Chemman

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Jul 13, 2013
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Maryland
MRRSM I have a question regarding the intake and valve cover gaskets. Are the Fel-Pro gaskets OK to use? I've always had good luck with Fel-Pro gaskets.
Thanks in advance!
 

mrrsm

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Yes...

Not only are they my "Go To Choice" for COMPLETE ENGINE OVERHAUL GASKET SETS... I also choose Fel-Pro because their TTY Bolt Sets for the GM Atlas 4.2L Engine Builds are also of the Highest Quality.

This choice can be especially troublesome because often there are none available from GM/GMC or ACDelco. There are only a few stateside companies that make Automotive OEM Quality Fasteners for this Platform... and Fel-Pro is a reliable provider of them:

If you need to Research and Confirm the Parts, Part Numbers and Parts Packing and Boxing information for the GM Atlas LL8 4.2L Engines... Please visit THIS Link to my "Flickr-Bucket" for the images on these items:


Here are the Fel-Pro Gasket Sets listing of what items are "Inside of The Boxes" for the various installation requirements for the GM Vortec 4200 Motor:

43350766702_9418299dbf_c.jpg43350766562_8b1d9c7540_c.jpg43350764232_e993780f86_c.jpg43350764162_0df0646fc8_c.jpg42494510795_04b8564a15_c.jpg
 
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Chemman

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Jul 13, 2013
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Maryland
Thanks MRRSM for answer! Greatly appreciated!

I also appreciate the link to the photos, you did a great job!
 
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Dadwagon

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I've removed the purge valve, looks to be original Delphi unit. There was lots of oil on the side that connects to the throttle body (toward the front of the vehicle), not much on the other side.
Should the internal valve open and shut when either side is blown into or sucked out of? Because I cleaned it and can't get any air movement either way. Would assume this has failed?
 

christo829

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Dec 7, 2011
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Fairfax, Virginia
Unless you applied voltage to it, don't assume it has failed. You say there's lots of oil *on* it, but what about *in* it, like just inside the connectors? If you don't see any oil there, odds are that the actual source of the oil is external, and there's nothing wrong with that valve. Besides, it's one of those components where if it wasn't behaving, you'd likely see a code.
 

Dadwagon

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Would the intake manifold gaskets failing like this cause the system to throw up a 455 Major Evap Leak CEL? Given the purge valve pushes air to the intake manifold, and the system monitors this during the EVAP MIL Ready test, I'm thinking my leaky IM is causing the 0455 Check Engine Light.
 

mrrsm

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Nope... Everything on that side of the Motor is always under at LEAST a partial vacuum when the Engine is Running. So if you had a a Serious Vacuum Leak of either some ...or all of the (3) Dual Port Intake Manifold Gaskets either due to Loosening Fasteners (NEVER use more that 89 Inch Pounds to Tighten Them Down) or if they've all aged out and have flattened out so badly as to allow Asymmetric Vacuum Leaks along the Aluminum Engine Head Port Faces... You'd either be getting specific Cylinder Misfire Codes (P0301-P0306) or else getting High Count Random Misfires showing up with a persistent P0300 Code. These two issues ...are mutually exclusive.
 
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Dadwagon

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The intake manifold still has to be removed so I can see where the leak is originating from. I've ordered the valve and intake manifold gaskets so I have them on hand in case both need a replacement. Having recently replaced the belt, fan clutch, and water pump, I think this project will be a piece of cake compared to breaking the fan clutch loose of the pump and squeezing the fan shroud out.
 

mrrsm

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Forgive me for disagreeing with you ...But THIS Task will turn out to be one of the most difficult PITA jobs that you will ever have to perform on an in-dwelling GM 4.2L Atlas Engine. There ARE a few Dedicated Threads worth searching for here at GMTN that cover the R&R of the Intake Manifold and/or the LL8 Valve Cover for verification of this unfortunate reality.

The reasons for this increased difficulty have to do with the odd placement and entanglement on the Driver's Side of the Engine involving the bizarre Metal Support Bracket that confines the confusing collection of Wire Harnesses adjacent the Power Distribution Center and for Wire Bundles feeding into the Three PCM Connectors. Go look at it... At First Blush... It seems innocent enough, Right?

ALL of that nonsense in your Field of View HAS to be removed prior to removing the Intake Manifold.
This problem is compounded by the need to employ an odd assortment of a 3/8" Drive Short Handled Ratchet along with a combination of extensions and the use of a 'very uncooperative Universal Adapter'. Some of the IM Fasteners are either VERY Hard to Reach ...or in the case of the one in the middle IM Flange area... is completely concealed under a Rubber Elbow Hose that MUST be removed first VERY Carefully so as NOT to Damage it during the R&R.

And lastly, because the Metal Bracket and the Intake Manifold have Fasteners that are positioned in ways that make it VERY Difficult to access and R&R them all by simply reaching over the top of the Drivers Side Fender. This of course makes it necessary to Elevate and Safely Support the SUV so as to remove the Driver's Side Wheel-N-Tire, This becomes necessary in order to gain enough access to and successfully R&R many these Damned Fasteners Through The Wheel Well. Just know going into this Job... It will be just as uncomfortable to Replace All of this stuff as it will be to Remove it All.

I am very Sorry about this... I wish it were otherwise.
 
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Dadwagon

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Eh, at least we have room to work with in this engine bay. I've worked on a Smart Fortwo 1 liter...parts are literally wedged into place with surfaces touching during the process of sliding parts into or behind the engine (motor mounts, for instance). I have big hands and the relative simplicity of all the old parts that have broken off my Buick have made the repairs livable, along with "room to work." Thinking back to my old Saturn DOHC...that valve cover had nothing on top of it. Just remove ten or so bolts, valve cover off, pop a vacuum hose off, done.

In reviewing what is causing my truck to throw a 455 Major Evap Leak code, I found out today that the nipple that usually covers the vacuum under the upper airbox (the thing that says VORTEC!) had a big crack on it. Thus, it had a minor vacuum leak that could have been throwing the EVAP leak code. Between super gluing the crack together and duct taping the plug in place, and replacing the fuel pump in the tank next weekend, I hope to be passing Smog soon.

And I say all of this optimistic shit knowing I do my repairs ON THE STREET without a garage or even a carport cover. Good times!
 
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TJBaker57

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Aug 16, 2015
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I found out today that the nipple that usually covers the vacuum under the upper airbox (the thing that says VORTEC!) had a big crack on it. Thus, it had a minor vacuum leak that could have been throwing the EVAP leak code


I wouldn't count on that being your EVAP leak. An EVAP leak does not involve engine vacuum lines on the engine side of the EVAP purge valve. To test the EVAP system the PCM closes the EVAP vent valve and opens the purge valve, applying some engine vacuum to the fuel tanks and lines. Then it closes the purge valve and monitors the fuel tank vapor pressure sensor to see if the vacuum holds like it should.

With a large leak I think the PCM won't even get to the point where it closes the purge valve because it isn't building the expected vacuum in the tank because of a large leak. Someone else likely know how it all works better than I and may chime in here...
 

mrrsm

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Your Best Friend in this Situation ...will be Using a Smoke Machine in order to *Winkle* Out Where the Problem lies.
 

Dadwagon

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Yep the Major Leak EVAP light came on soon after that nipple was covered. That port pulls a vacuum on my vehicle, was not internally plugged. The gas tank seems to be losing pressure as the gauge goes up and down as the vehicle warms up, and the gas gauge drops to Zero when I hit about a quarter tank. I'm going to replace the complete fuel pump as well as the fuel pressure sensor when I drop the tank in a week or two. I can look at the tank and the hoses, and once that's completed I either pass the MIL Ready Evap test or I bring the truck to my local GM dealer and have them run a smoke test knowing I've done all I can.
 

mrrsm

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Look into the condition of the Two Plastic Fuel Tank Steel Support Straps... Just in case they have Rusted through enough to warrant replacement while the opportunity is so nigh. :>)
 

Dadwagon

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Over the course of a day and a night I removed the intake manifold, cleaned it up, replaced the gaskets, broke a small chip out of the manifold (right at the center but the iron block should seal it because I'm never taking the IM off ever again), and reinstalled everything except the wiring harness that I will agree was truly a PITA. This has been one of the most difficult mechanic work I've ever done, and I have done valve adjustments and removed rear wheels out of shaft drive bikes...none of that compares, really. That final bolt at the firewall is the icing on the cake. Two days later I still am aching but the car is running fine.
How stupid am I to run the vehicle without the wiring harness in place? I plan to zip-tie all those wiring looms in place but I'm not even motivated to do that yet. The fuel lines couldn't be harmed without that piece of metal under them, right?
Just feels good to be on the other side of that work. Dropping the fuel tank in two weeks will be easy in comparison, I truly believe that.
Have a great day and may your trucks ride smooth.
 
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Dadwagon

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Last week I pulled the truck on a curb with wheels on the driver side up and dropped the fuel tank. Even with a bone dry tank of gas it was rather heavy, I estimate I had less than a gallon left when it dropped. The fuel pump was replaced along with the fuel pressure sensor. Broke the fuel pump electrical connector's clip while blindly connecting it but it is firmly in place. The old fuel pump looked like it had leaked a tiny bit around the ring lock which I had hoped would be a more tell-tale sign of evap leak.

Several days of driving later and the truck is running well, same as before. The flip side is, the MIL readiness for the EVAP system is ON instead of INC, and I'm tentatively saying this fixed my evap leak. I checked my notes and it went form a small leak code to a large leak over the course of a couple months of ownership. Have to wait for the Catalytic Monitor MIL to trigger to ON and I can go pass smog.
 
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Dadwagon

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Update: The truck no longer throws any CEL and I have successfully passed California SMOG check. I don't know whether the fuel pressure sensor or fuel pump gasket, or both were the cause of the large EVAP leak CEL, but I've put several hundred miles on it and all MIL have cleared to OK status.

Thank you all for your help!
 

Dadwagon

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And today, several weeks later with nothing but an oil and oil filter change and normal driving, I have a CEL and Tighten Gas Cap warning with a small Evap leak CEL. Unbelievable. Good thing I got the smog done already. Frustrating.
 
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Dadwagon

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Update: A fuel/smog line that connects the fuel tank to the charcoal canister in the back was the culprit. I knew I broke the clip during the tank install but had zip tied it in place and it held all this time! Well it stopped holding of course and lead to a Large Evap Leak CEL. Have replaced with a Dorman quick disconnect fuel line clip, the replacement worked perfect, thank you Vatozone. The CEL has not come on over a few drive cycles and about 100 miles of driving since CEL reset.
 

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