I have had my share of problems with my 2005 C6 NCM delivery 2/14/2005:

• Delaminated Roof (I have a transparent one while waiting for replacement)
• Noisy Differential (two fluid changes and then new clutch packs)
• Service Active Handling (new steering position sensor and BCM)
• Rear Hatch (two new switches and a reseated connector)
• Radio Inop under cold damp conditions (replaced)
• Cracked panel due to improper lift at dealer

These problems, although a pain, are not too serious. However, I have consumed what I consider excessive oil since the car was new and this I do consider a serious problem. I followed normal breakin procedures and my driving is mostly city.

After allowing 4000 miles for ring seating per GM recommendation, I was still using too much oil. After 8000 miles I started an oil consumption test.

The first test was 1800 miles/qt. I felt this was actually better than what I was getting, because the dealer put 7 qts of oil in and we had to drain a quart. I think I was slightly above the full mark.

The second test was 1400 miles/qt.

I sent an oil sample to Blackstone Labs for analysis. Basically, the results came back normal.

My dealer did a compression and leakage test:
I asked them to check the PCV system. They said it was difficult to test but they would order a new PCV valve and install it next week.

So, for you engine experts, what should I do if the PCV valve doesn't help? I really don't want my engine torn apart when it doesn't look like the diagnostic test have identified a problem. Most people on this forum seem not to require any additional oil between changes. I am a conservative driver, if I drove it like a sports car the oil usage would certainly go up. Adding oil, even Mobil 1, is not that expensive - but is there an engine problem lurking? Blackstone Labs recommended switching to non synthetic oil to seat the rings but I am going to do nothing to void the warrantee, especially since I purchased an extended warrantee.

The repair order said one spark plug was replaced, but the service advisor said the mechanic must have dropped the plug and broke it. I have 12,000 miles on the car so I don't think its going to get better.

So should I just live with it, try to get it fixed or what?

 

I'd get it torn down now,while still under warranty and before more damage is done!!!Obviously,there's a problem...

 

Is the dealer is telling this is with in tolerance?

 

GM guideline's is 1 qt in 2000 miles is normal. You need to decide even if they agree to tear it down do you want them to? They could cause more problems or mabybe it will get better on it's own.

 

The compression and leakage are within tolerance, the oil usage is not.

 

Try a slightly thicker oil (which these engines like anyways) such as 5w40.

 

LS1/LS6 in the C5 were afflicted by this too. They were re-ringed and turned out fine afterwards. But I will say I walked away from what was a mint ultra low mileage 02 Z06 after I discovered it was re-ringed.

So there is a downside since many Corvette buyers are **** - like me.

Tom

 

I would switch to dino oil for one or two cycles to help seat the rings, then go back to a full synthetic 5-40, as has previously been suggested. The dealer can't really detect what oil you are using, and they certainly can't void your warranty not using their recommended brand of oil. Now, if you start running 90 weight, that might be different.

You can also check to see whether you are getting blowby past the rings, or sucking oil past the PCV into the intake. If you feel the back of your throttle body blade, and it's covered with oil residue, you're getting oil vapors in the intake. You can run a catch can to trap the oil before it gets into the intake, and there is also a little restrictor thingy you can put before your PCV to reduce the flow. I don't remember the part number, just that it's an OEM part. Maybe somebody else knows what I'm referring to.

 

I agree with HITMAN99 and think Dino should be used in the breakin period. Mobil1 is too slippery for seating of rings.

 

This is why some of us here on the forum advocate an agressive break in, not the boiler plate language they throw in for every vehicle made in the manual.

You must seat the rings in these engines in the first 100 miles or youll never hone the cylinder at all aspects of heat, expansion, contraction and wear.

To baby the car is counter productive in the beginning. To avoid oil loss later best bet is to run the vehicle in second to red line, let it rev back down to 1500 rpm rev back up and repeat several times, cool down motor and repeat.

I suggest that if a poll were conducted, you will find that those reporting oil consumtion followed the manual and those that do not drove it hard in the beginning.

 

Here is one poll with a small sample size:

http://forums.corvetteforum.com/show....php?t=1449584

 

Nice. Not scientific but nice. Still, the racers and builders all will agree about honing the cylinders in the beginning for optimum performance. Seated rings and honed cylinders at all rpm bands=no oil consumption.

BTW, I still enjoy reading comments about break in periods for rear ends, thats funny.

As to your oil consumtion issue, I would not be happy with this at all. Tell us, do you now run the vehicle hard or do you still drive it as if it were a daily driver or when you broke the vehicle in ?

 

Most of my driving is done on 45 mph speed limit roads or 55 mph speed limit roads moving at much less. When I go to the dealer for repairs, I can take the interstate for a couple of exits and get up to 65 mph in fourth if I miss the rush hour traffic. Unfortunately, on weekends when there is no traffic I am stuck driving the family minivan.

When returning from NCM with the new car, I took the back roads in the mountains. A few hours on the interstate but I did vary engine speeds.

 

Your too easy on it. You gotta run this engine. Take it out, leave it in second, go all the way up to red line, wot, at rediline, take your foot off the accelerator and let it wind down to 1500 rpm, then repeat.

Do this a few times each time you drive the car. It cant hurt, but just might help.

Let us know what happens.

 

I break my new cars in the same way my Chrysler 300 SRT-8's owners manual tells me to do. After 60 babied miles, multiple short bursts at full throttle are recomended.

 

Live with it. Some burn oil and some don't. GM will do nothing to fix the ones that burn oil. It's very frustrating dealing with them on this issue. After 9 months I gave up and started moding my C6. Seems unless there's parts flying of they say it's not a problem. I'm surprised they didn't blame the roof problem on were you live or driving at excessive speeds.

 

I agree. Try and live with it, as you're probably in the 'high normal' range of oil consumption. Keep an eye on the consumption rate, and if it's getting worse I'd dump the car before the warranty's out. I have used thicker oil and additives like STP in the past with good success, but I don't know about using this kind of thing in our cars today.

 

1400 miles per quart. Let GM fix it.

 

See the post I put up for a guy with the same problem you have:

http://forums.corvetteforum.com/show...il+consumption

I guess after reading your post GM really didn't learn their lesson with the LS1/LS6s. The owners manual of my C5 said to expect between 5000 and 15000 miles between oil changes (as calculated by the engine computer) before your CHANGE OIL message comes on. Remember, your car runs full synthetic which can go a lot longer than regular oil between changes. The 1qt/2000 mi spec came out [U]after[U] GM found out they had oil consumption problems. Any engineer worth his salt will tell you that there is a design problem if you have a production car engine burning a quart every 2000 miles. A properly designed engine, in my opinion (and I am a mechanical engineer), should burn NO oil or very little (less than a quart per 5000 mi) oil. For all the pain and BS I've been through with GM, and having experienced first hand their utter lack of technical assistance to the dealer, I would advise you get the car bought back under lemon law if possible or dump it and consider whether you would want to risk finding another one. Good luck.

 

I've always found it odd how some LSx engines will burn tons of oil while others will burn almost nothing. My 98 LS1 uses no oil at all between changes. Even when I've gone 9000 miles on the same oil, the level on the dipstick has not moved. But yet other people burn a quart every 1 or 2000 miles, even on low mileage engines which have not been abused.