meridock

Team Z,


I purchased a used 2010 Z06 in Feb 2015 that had 5k miles on it. I drove it off and on over the next 8 months whenever I was not on travel. I complained about what I thought was an "oil smell" whenever I came to a stop. I noticed in Sept that I seemed to be down on oil. I added and added oil (5 quarts in 5000 miles)


In Oct I dropped the car off at the dealer and they proscribed an "oil change and test in 2k" approach.


Well today I dropped it off with a resulting phone off 3.5 qts in 2k miles. I then authorized a full test of the car - first step is a test of PCV system, then a blow down test, and such. I plan to document this over the next few days.

Dirty Howie

Good luck and interested to follow this.
I use 1/4 to 1/3 qt every 3-4K miles.


DH

AzDave47

Hopefully they find a leak and repair it. If not and blue smoke out the tailpipe and your oil consumption is well below the 1Qt in 700 mile that GM considers excessive. Your car should still have the powertrain warranty, at least.

stefuel

Although not a LS7, I am going through this right now with GM. My wifes GMC Terrain is gobbling oil. A week ago we were going out shopping for new bedroom sets for our 2 boys. I usually insist on driving my big-a$$ pick-up because I hate the Terrain. She was complaining of a noise so we took it. 30 minutes into the ride I stopped at a set of lights. When I stepped on the go peddle she said there that noise. She thought it was a exhaust leak. I said nope. sounded more like every lifter bled down. Checked the oil and it was down 4 quarts in a 5 quart engine. No pressure gauge and the idiot light never came on. Brought it to the dealer and discovered it's a known problem with this 4-banger. Dealer changed the oil and it's now in a 1000 mile consumption test. They assured us it will fail and will be repaired at no cost. Not replaced but repaired. Pull the pistons and replace the rings.

Rock36

Subscribed, I'm interested as well.

I might be close to that 1QT every 1000 miles, but I just added a QT a few days ago and I will watch the mileage this time.

I don't show any kind of blue smoke on start up however.

EdsC6Z06

Don't have the link but there's a thread about crank cap bolts coming loose and falling out of the side of the block. Can leak under high rpms.

meridock

Couple of points - the tech called "GM" to discuss this and one of the questions asked wasn't "is the car tracked" but "does the car spend more time about 3-4k RPM than below?" cause if so GM considers a quart every 500miles "ok" in my specific car the car runs 2-3k in traffic and back and forth to errands (yes - I take my car shopping ) However, in this case 1 qt every 2000 miles is the bingo number, and since my consumption was nearly double that I was in a warranty situation. (GMPP!)


Car was thoroughly checked for leaks and nothing was found. today will be PCV system replacement (not much in diagnostics on this i guess,) all sparkplugs will be pulled and a blow down test performed.

Honestly, I *almost* hope it is not a PCV thing, given this early in the life of the car to be almost half down in oil for x amount of time, and 30% down for some more. I can't imagine the potential for long term effects. The next owner would have problems potentially, so I hope GM can find something to cause maybe a shortblock replacement or some such. I only plan to keep this car till next year if everything comes together. But I do not want to have a time-bomb on my hands or the next person.

The Rex

A quart every 500 miles is considered ok?!?

meridock

If tracked and/or driven VERY aggressively e.g. I live my life a 1/4 mile at a time, it was indicated that 1 for 500 was not unreasonable and would be considered ok. (likely they would have still dug in but not confirmed)


So while I was typing I got the call, my car is ready. They replaced the PCV system (it is a valley tray in this motor,) and did the leak down test. the cylinders were within 2% of spec across the board.


Next step is another 2k mile evaluation.

The Rex

Well,
if that is the case,
and with all the valve issues...

I am seriously reconsidering buying another Z06.

meridock

I did some research on this forum a but - and a number of track cars have this consumption rate. Some comments from the gallery have indicated varying levels of consumption ranging from 1 quart per oil change to a bit more.

I am leaning towards a GS or Stingray with a Mag Ride as my next car. the Z06 is just too high strung for my normal plebian usage. (blasphemy in the Z06 forum )

AzDave47

I collected 4 oz. of oil just in my PCV catch can in 69 miles of road circuit running. I'd be happy if it only used 1 Qt. in 500 track miles, BUT I don't use 1/2 quart in 2000 miles of street driving, most under 3500 rpm. GM considers 700 miles per qt. excessive for a street driven car.

pkincy

I believe that is a throwback to GM not wanting to replace all the 2001 Z06 motors as they all used a qt/1000 miles it seems. Well if not all a large percentage of them did. So GM deemed that was "normal." I kept mine only a year and it was consistent in needing a qt every 700-1000 miles. Not overly expensive but wasn't boding well for a long term keeper.

Still think that is the best Corvette I have ever had however.

NDAGRUV

I know this will sound like blasphemy to purist vette heads - but how about changing over (for one oil change cycle) to conventional oil???
It certainly can't do any harm. And we all know how slippery synthetic oil is. As a matter of fact, if you rebuild your own engines, you should know that for the first oil change cycle, they FORBID THE USE OF SYNTHETIC OIL..

Just a thought. I'll try it if I exhibit any excess oil consumption or loss. If I do, I'll post my results here, but I've got 90% oil service life at present - so it may be awhile.

GOOD LUCK!!

stefuel

They claim the rings will not break in correctly with synthetic

AzDave47

Requiring conventional oil for break-in is old school. Most manufacturers now use synthetic only in the engines. Corvette has used Mobil1 exclusively for 2 or three generations at least.

meridock

Update... Picked up the car yesterday. On the drive back I did not smell at odd times of oil burning that I had previously at each oil change.


I will be in the 2k oil check cycle for the next few months (likely Oct before 2k miles.)

NDAGRUV

It is common knowledge, at least among OLD Schoolers like myself, that piston ring seating with conventional oil in "WAS" the only way to break in an engine. In other words, you used conventional oil's for a time (some used to designate 25k miles) before switching to Synthetic oils.
Granted, technology AND engine building tolerances have changed SOMEWHAT over the years, but there is (to me) an obvious lack of proper ring seating among many of today's engines.

I'm bumping on 69 years, and, yes I even remember SEEING the introduction of the Corvette to the world! It was SOMETHING WORTH REMEMBERING!!
I've built many engines over the years, so it seems quite obvious to me what the issue is, and if I have an oil consumption problem I will dump the synthetic, install conventional oil and ride her hard for a couple thousand mile and switch back to synthetic.
NOT that big a deal, in my humble opinion.

AzDave47

That may help the OP, however my Z06 has only had synthetic in it's 45K miles and except for track use only goes thru 1/2 Qt of M1 every 5K miles.

Yes I remember old school when conventional oil consumption of 1 Qt every 1000 miles was considered great. There was a reason in the 60's when I worked "full service" gas stations that we checked the oil every fill up, which usually happened every 200 miles, not the 450 our Z06's can get cruising at 80 MPH.

My 95 M3 only saw synthetic and the leakdown test at 133K miles (40+ track days included) was 3%. Old school engines would never have done that. I sold the drive train at 169K miles and it used 1/2 qt synthetic every 2.5-3K miles. Synthetic oil can seat modern rings.

2k Cobra

Sold my 07 Z for a 13 GS. 30K miles and still smiling!!!!