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Another dealer likely overfilled oil during oil change
I took my Z51 to the dealer for the 2nd "free" oil change and asked them not to overfill the oil as my car is Z51 and has drysump. After they were done with the oil change, the service consultant gave me the remaining bottle with half a quart of oil to top off in case it was low. Drove my car home, parked it and forgot to check the oil within 5-10 after I turned it off. It sat in my garage since Monday then took it out yesterday to wash it. After I pull it out of the garage, guess what. I notice, an oil stain where it was parked. I realized they have likely overfilled it. I read through the posts and some recommended to check the air filter as oil "MAY" have got into the air intake.
I checked the oil level and it seemed to be at the max hash mark on the dipstick.
My question is this, Since the oil level appeared to be at the max mark and not higher, but there was oil on my garage floor, is the air filter "MAY" be or is it "LIKELY" compromised with oil. Should I should take it back to the dealer to have them check it?
Depends on how big of oil spot you had on the floor. If it was just a few drops it could be a loose filter or drain plug or they spilled some oil and it finally dripped off. If oil is at the fill mark I would say everything is fine. Just keep a eye if you find anymore oil leaking, if so, bring it back to dealer for them to check everything is tight.
many times the oil on the floor is where they made a mess underneath when changing. probably additional drops that they did not clean up.
At the high hash mark is fine. If they gave you the half quart when you left, then the person doing the change knew what they were doing. I would not be worried about that part... clean the oil spot, and see if it keeps coming back. Then I worry they didn't tighten one of the drain plugs.
Almost sounds like they may have spilled some oil when servicing your car and neglected to clean up their mess. If the oil level is not above the max level mark, then its probably OK and oil most likely did not make it to the air filter. Look for any oil residual around the oil fill, wipe it up, and then park in a different spot in relation to the already know oil spot on the garage floor. If it continues to be a nuisance, then take it back to where it was worked on. Good Luck!
With the complaints about an oil smell after having a dealer change oil in a dry sump, a spill while filling is my guess!
Having changed all my own oil in my 2014 Z51 and Grand Sport can validate it easy to fill the dry sump tank too fast! There are baffles in the tank, to separate air and oil.
I don't have a "fancy funnel" BUT put a large rag around the fill opening and the wide mouth funnel I use and pour very slowly! If not, it will come out of the top. It's NOT like wet sump that you're pouring into essentially a bottomless pit.
If oil spills, a good tech will clean the front and sides of the tank. But can't reach the back of the tank as it's very close to the fire wall. That is exactly where the cabin air filter cover is located. Pretty flimsy plastic cover! My guess is that is what causes folks to smell oil for several weeks after the engine starts! I have never smelled oil as I have never had oil overflow!
Although I keep my level half way between MIN and MAX, at the MAX level it should NOT spill over into the air intake tube and soak the filter.
The OP should some clean pieces of paper under the car and note where the drops are coming from IF it still occures.
I'm going with the "didn't wipe the excess oil off undercarriage when finished" and may be tightening issue on drain plugs or oil filter. Hopefully that is all it is and not the overfill.
Thank you all for your input. I ended up cleaning the garage floor and underside of the vehicle as much as I could reach. Then I put a piece of cardboard under the suspect area. Remeasured the oil several times within 7-8 minutes after the car was to turned off and every time, the oil level appeared to be at the max hash mark. No additional oil was dripping as the cardboard was dry. I still wanted to let the service advisor know so I ended up calling my service advisor and told him that I noticed an oil spot after the oil change.and he said to bring it in to check it out. I took it back to the dealer and asked the advisor if the mechanic can look into the air intake and check if there is oil in the intake or air filter. I also asked if I can see once he has the air intake disassembled. He took it apart and I went back with him. The air intake was clean but there was a little oil residue on the filter. I talked quite a bit with the mechanic and got distracted and let them to put things back together. They brought my car out and asked if the air filetr was replaced and the advisor indicated that it was not. I questioned if it should have been and he said that it was not that bad to require a replacement and they had seen many Z51's, Grandsports, and Z06's with oil on the filter.
I didn't want to make a stink about it as it was my first visit with this dealership and I am hoping to not sour it from the get go as I am planning on keeping the car for long term and surely will need to go back for future maintenance and warranty items.
I also figured if need be I can replace the filter next time I go in for a service visit.
The question I have, if the air filter has "some" oil on it, will it affect the vehicle's performance or harm anything in the long term.
^^^
FWIW, I had my September 2013 built C7 Z51 13 months before GM had the bulletin that said to change oil at 500 miles due to the "possibility" of oil foam burping into the air intake tube, running down and soaking the air filter and then dripping on the ground.
When I added a low restriction aFe oiled cotton air filter I looked carefully at the OEM air intake tube and OEM paper filter, not a drop of oil. I had changed my oil months after I got it at ~1500 miles because I wanted to NOT anything to do with GM requirement. In fact for the early C7's the dealers were not changing oil "free" until the OLM read less than 15 to 20% for fear they would not be reimbursed by GM. We had 4 "free" changes but only in the 1st 2 years. In any case, I change my own oil to avoid improperly lifted car, overfilling etc. I do it so I know it's done right.
That said, I would not worry about a small amount of oil on the paper filter as much as possible contamination of oil that got on the MAF that is in the center of the air tube just after the filter. However if it was a small amount of oil that is probably no problem.
SIDEBAR
Some folks worry that oiled cotton filters can contaminate the MAF. In fact aFe offers a more restrictive replaceable paper filter option for that reason. The filter comes "preoiled" but you can not feel it. I have used oiled cotton for years and when cleaned and reoiled (which I did whan I switched the aFe from my Z51 to my Grand Sport) and you could not feel the oil. To do it properly takes time. After the filier is cleaned and allowed to dry (I wait overnight) a small amount of the proper oil is placed on the top seam of each rib and allowed to wick to the bottom. I wait ~1 hour and look for areas at the bottom of the ribs and where it is still white (the oil is purposely colored) I put a drop of oil in those areas. It usually wicks to where it is all a uniform color.
I’ve been changing my own oil in my Z’s for the last 10 years. For this very reason. If you check the dipstick the proper way and the oil is at the top hash mark, you’re good. The technician may have spilled a little oil which led to the oil stain under the car. When dry sump first came out, it wasn’t uncommon for the service technicians to overfill the tank. Many horror stories on the forum about this back in the day. Now that it’s been around for the last 14 years, mishaps are a lot less common.
This stuff makes me happy that I have a non-Z51 Stingray with a 'wet sump' oil system........much simpler. Of course, I will never track my Corvette, so I don't need all of that extra stuff.
If it is not showing overfilled, I'd suspect they just slopped some around in the filling process. But, if it will ease your mind, do check (or have checked) the filter.
I had my oil changed at my dealer . when I got home it leaked out a small puddle under my GS. The oil was leaking out of my air filter box. I called yhe dealer and talked to the mechanic that worked on my car to see if it was over filled and he assured me it was not. About two hours later he showed up at my house (20 miles from town) with an air filter in hand. He cleaned the filter box,ducting, and mass air sensor and all is good. He has a fill funnel that screws into the fill spout so he can't spill as easy but we found out if it filled to fast it can run oil down the vacume line at the top of the fill spout to the air box. You might look at your filter to see if it is wet.
^^^
Hmm, very interesting! Perhaps that filter that attaches to the opening is NOT the safest! Makes sense to me as the hose that "burps" air into the air intake duct exits at the top of the dry sump tank!
Since I just use wide mouth funnel that does not fit tightly I can see that the oil takes time to flow past he baffles in the tank! I have to pour very slowly to avoid it coming out of the fill opening! In fact, I put a rag around the opening, "just-in-case."
Regardless of whatever funnel is used MUST pour slowly!
SIDEBAR
If interested- all dry sumps, to remove all oil from the engine and pump to the dry sump tank must also pump a lot of air. In fact a racing dry sump has large scavenge pumps and creates a vacuum in the crackcase! The C7 pump is to small to produce much vacuum.
That pumped air must be separated from the oil before it is pumped back to the engine from the tank bottom. There are baffles in the tank to assist that separation. EPA does not allow that air to just be vented as it may contain some oil vapor. So the air "burps" through a hose at the tank top to the air intake tube. Can see how if a funnel that connected to the opening was filled above the tank some oil would flow into the air burping tube!
Another question now that I read above about others experience. I have now changed oil in my Z51 twice (first 3 years were under the factory warranty that came with 2015 MY Corvettes), and have used a narrow outlet funnel, which may be why I've never had an issue with spilling over the top of the tank. The oil will back up the funnel if you pour too much to fast. So I just pour slowly. So again, I just wonder, am I lucky? Don't know but in any case running over the top of the tank has not been an issue for me.
Are the folks who have managed to run over the tank using a wide mouth funnel or something?
Also, where in the heck (other than overflowing the tank and running down) is it possible to get oil on the under carriage when draining oil and changing the oil filter? The oil filter hangs straight down and there's nothing between the oil tank drain holes for the draining oil to splash on.
And trust me when I tell you, I can make a mess as good as anyone. Just don't get the issues.
This stuff makes me happy that I have a non-Z51 Stingray with a 'wet sump' oil system........much simpler. Of course, I will never track my Corvette, so I don't need all of that extra stuff.
Very informative posts here!!
"Much simpler" is an exaggeration. The dry sump does not take a rocket scientist to change the oil. You just have to pay attention to the simple procedure. It really only has a couple of extra steps that you have to follow to do things right. It just has one extra drain plug to remove and you have to check the oil level after warming the engine oil up to a specified temperature.
On edit: The techs can just as easily botch your wet sump oil change as well by under filling, over filling, leaving the oil drain plug loose, or leaving the oil filter loose.
The mechanic I had on my car has a funnel that fits tight on the oil fill spout. can't leak. He just upends a jug of oil and leaves it in the funnel. Oil goes in to fast and backs up and runs down a vacume line to the air box. You're good with the skinny funnel because the oil goes in slower. look at your car. There is a tube just forward of the fill spout and if you follow it , it goes to the air duct just past the air filter.
06-07-2019, 12:44 PM
Another dealer likely overfilled oil during oil change
With the complaints about an oil smell after having a dealer change oil in a dry sump, a spill while filling is my guess!
