TennisFreak

I'll break this up into 3 posts: Problem, Dealer and Fix, Getting her back

My car is a 2015 1LT Z51 M7 that I custom ordered and picked up from the dealer on May 15 2015.

It currently has ~5400 miles on it.

Problem

So most of my small quibbles had been just some fit at finish issues where GM went cheap or was sub-par on initial quality. Cheap clear coat, roof rattles like crazy (I can make the rattles go away but they always come back), loose overhead light buttons that are cheap, and other really minor things.
Nothing to get butthurt over just small things that I felt could have been better.

Sunday before last I go out to wash my Corvette and after pulling her out of the garage I see oil on the floor.
I was like "WTF!!!".
It was coming from the right side of the car right where the dry sump oil tank is.

I open the hood and at first it appears that my Elite clean air separator oil cap is where the oil is coming from. I inspect the cap and it was not clogged or dirty and it seemed to be on tight.
Oil was all over the top plastic housing of the dry sump tank and dripping all down underneath the car.

I decide to clean up the oil and begin troubleshooting what could be wrong. My first step is to remove the elite clean air separator from the equation and put the stock cap and hoses back on the car.

After cleaning up all the oil on the sump tank (this was a bitch because of room) and underneath the car, and putting the stock oil cap on I start the engine and let it warm up to operating temperature. I then rev the engine quite a bit for about 3-4 minutes and go check to see if I can see any oil.

No oil visible. I decide that maybe I need to drive the car and put it under load to build some pressure. So I take the car out and drive it a few miles around the area. I redlined her once and made sure I had a few hard wide open throttle acceleration runs.

Get back to the house pop the hood and go look under the hood to find oil down the side of the dry sump tank. This time there isnt any oil near the cap or the top and it distinctly is coming from the side of the plastic top. I am attaching a picture of where I could see the oil coming from.

At this point I decided there is nothing I can do to fix it as I see no place where bolts or mounts could be tightened.

She is going to the dealer first thing Monday morning.

TennisFreak

Dealer and Fix

Monday morning I go straight to the dealer and arrive 8am to get her looked at.

I pull in the service center and am greeted by a service rep. He is very nice and courteous and asks me what the problem is.

I tell him my car is leaking oil.

He apologizes and tells me that he will get someone to look at it and asks me if I need a loaner car.

I tell him "I don't know it depends on what you find and how much effort it will be to fix it. Can I show you what is going on?"

He tells me "No you don't need to show me I will have a tech look at it later on, lets get you a loaner car."

I am "But what if I am wrong and there really is no oil leak, you are giving me a loaner car for no reason."

He proceeds to tell me my car has to go in line to be looked at and based on the number of cars ahead of me it will be 2-3 days before they get a chance to look at it.

I plead with him to just take a quick look and tell me if I am crazy but he says no and that I don't need to explain anything the tech will look for himself.

Anyways I take the loaner car (free of charge) and go to work.

Wednesday comes about, and up to this point I have not heard anything, when my service rep calls me around 1pm.

He tells me that they found the problem and the car is ready to be picked up.

I ask him what was the issue and he tells me "A leaky oil cap".

I tell him "No that cannot be the issue as I double checked two times for that exact problem"

I proceed to explain that upon a quick look that might appear to be the issue and this is why I wanted to go over the oil leak before I left the dealership.

He is very polite a courteous the entire time and asks me what I think is going on. So I go over the troubleshooting process I did at my house (in first post) and try to explain where I think the leak is coming from.

My service rep says he is writing all of this down and will send the car back to the service rep to inspect based on my notes. He says they will look right away and try to call me back that afternoon.

The days goes by and I hear nothing.
I decide not to be impatient and a pain in the butt. Give it until Thursday and they should call back.

Thursday around 3pm I've heard nothing and decide to call.

I get a hold of my service rep and he says "Yes we have ordered a new dry sump oil tank and will be installing first thing in the morning".

I say "Oh so you did find the oil leak after all?"

He says (and I am dead serious here) "No we decided to just replace the whole tank based off your description of the problem."

I say "I'm sorry, did you say that you did not look at it again".

He says "Your description of the problem and your steps to troubleshoot it sound very thorough and we think you have a good understanding of what is going on. So we will just put in an entire new dry sump for you. I will call you as soon as the car is ready to pick up."

At this point I am just blown away.

Is the dealer incompetent? Do they even care about what the real problem is? Was it all in my head?
If there is an oil leak and the tech cannot diagnose it right, how in the hell can I trust him to fix the damn thing right?

I mean I just have never had a dealer experience where they would "take the customers word" and just start repairing crap without even knowing what the real problem is.

Up to this point the dealer and my rep have been extremely accommodating and courteous. I was actually a little concerned with how willing they are to just hand out loaner cars with no care.

Friday morning I get a call at 8am from my rep telling me the dry sump tank has been installed and I can come pick my car up.

TennisFreak

Getting her back

Friday I leave work early at 3pm and head to the dealer to get my baby back!

I've never missed a car so much in my life!! The Chevy Malibu loaner they gave me SUCKED *****!! I felt completely dead driving that stupid thing.

I arrive and go to the service counter and they ask me to sign for the work. I ask them if I can look my car over before I sign and they are completely fine with it.

My service rep has the car pulled into the center and we go over her together. I do as thorough of a check as possible.

Dry sump is definitely brand new.
Everything looks like it was put back together very well, no immediate missing bolts, fasteners, etc..
All the oil leaking down appears to have been cleaned up, even underneath car.
I dont see any dents, scratches, or blemishes on the cars body or wheels.

I sign for the car, shake my service reps hand, and drive off down the road.

Two miles later I reset the instrument cluster to my preferred setup and notice the oil temp is not reading at all.

CRAP.

I turn around and go back to dealer and pull in service center. I find my service rep and show him what is going on.

The techs had all left for the day but the service/shop manager was still there. My rep asks him to fix it so I can take my car home.

He was nice and had no issues with being asked to do it.

After 15 more minutes they bring my car back and the manager told me the tech just forgot to plug in the temp sensor and my car is good to go.

I thank them and leave.

I've been driving my car ever since and I have put her through some really hard WOT sequences. I figured if something was not done correctly I want to push the car now and find out sooner rather than later.

All seems to be good so far. The weekend has come and gone and my car seems to be back to normal.

JerryU

Curious who did the last oil change? If oil was coming out of the Elite Clean Air Separator base overfill could have been an issue.
Won't worry about the dealer, they got paid by GM to replace the dry sump tank! Perhaps he needed some service work!

TennisFreak

The clean air separator does not have any overfill to fill up. It is just some wire mesh that the air passes through to catch oil vapors which should then trickle back down into the dry sump tank through the cap.
When I took the clean air separator off I took it apart and checked it and there was no oil accumulated. I even put my mouth up to the hose and blew through it to see if it may have been blocked. No blockage detected.

The dealer did the initial 500 mile service oil change.

I have not had the oil changed since.

I have not put the clean air separator back on as of yet.

Rooster OG

I'm glad they fixed it for you. That's a really expensive way for GM to fix problems, but it worked for you! Hopefully it won't happen again because no one has any idea what was wrong to start with.

COSPEED

Your experience is very common. The techs are rarely spending the time to truly inspect and determine if there is an issue as the way the reimbursement system is set-up it is far more cost effective (profitable) for the dealer to just swap the part as quick as possible, as all is based on the time allotted to do the replacement/fix.

The issue is nor real common, but common enough.

How is your Elite system working? Do have their latest E2-X system designed just for the new GDI engines? You want to make sure you stop all the oil ingestion, and that is just what the new systems do.

JerryU

I have an Elite Clean Air Separator, that is why I asked. Compared to the standard ol fill cap in uses an "O" ring to seal so thought it was possible it came from there. Dealers have been know to overfill the Z51 by going by the book for the amount versus checking the level, which is harder than it sounds and takes some time to under-fill and top off. If you have driven ~4500 miles with no problem it wasn't that.
This pic is from the Service Manual. Not a lot of places to leak at the top accept past the Clean Air Separator "O" ring. As noted there is a seal between the top and the bottom sections.

TennisFreak

Shoot I thought I had uploaded a picture of where I thought the oil was coming from. Here is the picture.
It seemed to be coming from right here on the plastic top side of the dry sump housing.
Not sure if this is just design or a pressed seam of some type.

bob guzzy

Its plastic, probably years from now owners will be replacing them with aluminum after market pieces.

COSPEED

That joint is "sonic welded" as the intake manifolds have been for years. Leaks are not common, but do happen. Sound waves/vibration melt the 2 parts together and they should last over time, but time will tell as most know the LS2 intake manifolds were known to leak between the runners.

Let me know if you need any assistance on preventing the intake valve coking all of these engines are prone to:

TennisFreak

Thanks for the explanation of how that part is put together coSPEED2!

COSPEED

Also, yours shows the new updated cyclonic separator introduced in the 2015 models, and that is a huge improvement in oil control over the 2014's.

Good thread TennisFreak!

Al Engel

I had an Elite oil air separator on the sump tank on my '14 Z51. Leaked oil as you described. One of the O rings on the oil separator cracked and oil leaked past the O rings with the apearance that it was coming from the area of the sonic weld of the GM tank. Cleaned up the mess with engine degrees and water...a lot of oil down the inside of the fender well and then blown all over the bottom right side of the frame and rocker pannel. Removed the Elite separator and reinstalled stock components. No problems in the 8K miles since. With proper oil level and after Initial oil change, I have concluded the oil separator on the sump is not necessary and it was the Elite product that was the source of the problem. I do have the Elite 'dirty side' catch can and that is doing its job properly. All the above is from my experience and is my opinion. Others may have different results and different conclusions. Have a nice day....

AORoads

So you faked out the dealer by taking out the extra part, got a new dry sump, and haven't put back in the extra part. Why not put it back in and see if it's the problem? Worth a shot, esp if you still have the originals.

\Boost Monkey/

I'm going to comment on a brief part of your write up that I noticed.



Those stupid piece of chit overhead light buttons. Thank you as I have never seen anyone mention that before, but it annoys me. They like literally just hang there... All loose like they are about to fall off. It's the cheapest garbage I've ever seen on any vehicle.

Anyway, that's all I got. Stupid fuking buttons.

TennisFreak

LOLOLOL I've always thought the same damn thing. I mean COME ON did GM save 1/10 of a penny by putting that cheapo f'ing button instead of a a flush solid button?

I will put the part back on this next weekend. I want to give one solid week before to make sure the work performed and the new part are good.

Once I put the part back on if I see leaking then I will no its the clean air separator from Elite.

To be honest I dont think the clean air separator was/is doing much. I regret paying the extra money for it.

JerryU

With all the forum reports of oil dripping from the air cleaner, the $99 was worth it, IMO. Can't see that is was doing any harm and perhaps stopped some oil burping into the air intake. I installed a Cold Air Filter system and did not have a drop of oil in the air intake tube or on the OEM filter. My oil was never above the full line and after I made the 1st oil change I have kept it 1/2 quart low.

COSPEED

Correct. For all 2014's it is a great mod, but also all LT1's need the dual outlet Elite E2-X or the ColoradoSpeed can that provides constant evacuation suction so pressure never builds as this really does a good job of preventing any burping, and it is the latest generation for GDI engines that cannot tolerate any oil ingestion.