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losing oil

Old 10-29-2012, 07:01 PM
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baxsom
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Default losing oil

My low oil level message has came up twice now in the last 1000 miles and for the life of me I cannot figure out why. As soon as it comes on, I let the engine sit so all the oil drains back into the pan and check and both time it has been half way up the dipstick. It takes about 1/4 of a quart bottle to get it back to the full line. My catch can is empty. The throttle body is clean. I pulled the plugs and the electrodes are greyish and the white ceramic is white. There is no oil on the driveway. I cannot find any oil leaks anywhere. The oil pressure is good at 40psi at idle. I cannot find any leaks around the valve covers, oil pressure sender anything. The car also has the 2004 valley cover with the PCV delete conversion if that means anything also. Is there a common spot to look for a "mystery" leak.

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Old 10-29-2012, 07:10 PM
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Vetteman Jack
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Perhaps you just have an oil level sensor going bad. Might want to check that out too.
Old 10-29-2012, 07:51 PM
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duegatti
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Along the lines of what Vetteman Jack suggested, I believe there is a bundle of three or four wires, including the wire to the oil level sender, in the vicinity of the starter. My insulation had been destroyed down to bare wire. I've been told that can cause false low oil warnings.
Old 10-30-2012, 08:32 AM
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sunchaser73
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Originally Posted by baxsom
The car also has the 2004 valley cover with the PCV delete conversion if that means anything also.
Which part number valley cover do you have? I ask because there are two "versions" of the valley cover:
1) p/n 12577927 which has the fixed-orifice PCV and oil separator
-AND-
2) p/n 12568002 which, as far as I can tell, only has the fixed-orifice PCV
Neither of these are really a "PCV delete" as you say. The valley cover provides an outlet to vent any crankcase pressure. A fresh air source is still required or your results can/will be undesirable.

Case in point:
I installed #2 in December, and I noticed that my catch can was filling up after a few hundred miles, along with a corresponding drop in oil level.

About 2 weeks ago, I changed valley covers to #1. Almost 400 miles later and there is barely a drop of oil in the catch can. Perhaps it is a slight amount of overkill...running the valley cover and a catch can, but I'm not a big fan of sucking oil into my intake and through the engine.

You also mentioned that you checked the TB and it was clean/no oil...have you checked inside your intake manifold? Any indications of oil getting into your cylinders...such as puffs of bluish smoke when you start the engine?

Has your engine been modified at all? If so, how?...H/C or full build?

I would suggest that you verify your full setup, including the valley cover's part number. Also, check your fresh-air supply hose(s) and the return hose from the valley cover. It is possible that you excessive crankcase pressure resulting in blow-by and thus, your oil consumption...

Mine may not be the sole solution to your oil consumption, but it is worth a look, IMHO. If you are interested, send me a PM with your email address...I'll send you some info that I cannot post (from my iPad) up here. I have a few PCV System schematics and pics of the two that will show the difference...

Anyway...hope this helps

Edit: I did some additional searches related to the "old" valley cover (12568002) and several people over at LS1Tech have said that this particular valley cover does not have the orifice. It seems to be "common knowledge" that this valley cover has no oil separation capability built-in...but I was under the impression that it did have an orifice-type PCV...
Now I'm thinking of disassembling my "old" valley cover to really see what is going on in there. If there is any interest for pics of the internals of the "old" valley cover, let me know...I'd be happy to snap a few and post them.

Last edited by sunchaser73; 10-30-2012 at 09:14 AM. Reason: Additional info/commentary
Old 11-16-2012, 06:03 PM
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baxsom
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Hi,
sorry it took me so long to get back to this. been busy with getting ready to move to Korea. soooo anyway,

Long story short, it is still using oil.
I put in a quart two weeks ago. I put in a quart today. I took a 300 mile trip today. I filled it full (the quart low) and drove it. I got the low oil level message 32 times today.
I stopped after the first one and checked and the oil level was at the full mark. I stopped at like the number 15 message and again full. I quit checking after that.

The car itself is a heads cam car with FAST intake.

As far as valley cover part number. I am honestly not sure. It has been like 6 months since I installed it and when I ordered it I just called GM parts house and said I want the 04 LS6 valley cover that will allow me to delete the PCV valve. 8002 still require an actual PCV valve. I got the other one. I followed the LS1 to LS6 valley cover install to the letter. I blocked the one tube on the passengers rear, plugged the crossover on the drivers rear, and ran the passengers front tube to the throttle body. From the valley cover to the intake has a catch can installed. I cant find any oil anywhere. I was under the car just this past weekend with a flashlight and cannot find diddly leaking.

So it seems like I have two problems, a faulty sensor and it is using oil. Dangerous combination.

Where is the oil level sensor? Is that the one that is plugged in right above the oil filter?
If I take it out does the oil need to be drained first or can I leave it in?

There is another large sensor looking thing looking like it is going into the oil pan near the starter? What is that?

There is no smoke at all, I had a buddy stand behind the car while I started it, revved it, etc. I then had him follow me as I got on it. No smoke. The plugs are white with normal colored electrodes, The catch can is empty, the throttle and intake are clean. The hose that goes from the front of the passengers side valve cover to the throttle body is clean. I am at my wits end where this oil is going.

Sorry if this is so long but I tried to be as detailed as possible.

Last edited by baxsom; 11-16-2012 at 06:09 PM.
Old 11-17-2012, 07:21 AM
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baxsom
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Originally Posted by 8VETTE7
Oil level sensor is on the back of the oil pan on the passenger side near the starter. You will need to drain the oil to avoid getting an oil bath. Have you examined the connector and wires to the sensor? Not an uncommon problem for them to get fried on header cars.
I actually havent examined it yet but i did go ahead and get a new sensor. for 25 bucks, the hassle of lifting the car and crawling under it once is just worth it. that will hopefully solve the continuous low oil message leaving me only with the actual oil usage. It has to be something in the PCV system. It never used a drop until i went to the 04 LS6 valley cover. Just like in the how to, I capped off the rear of each valve cover put a catch can inline between the valley cover and intake. I am thinking about putting a breather on each of the capped off nipples on the back of each valve cover to see what that does.
Old 11-17-2012, 04:56 PM
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It sounds like you have two issues:
a) a bad oil level sensor, or associated wiring.
b) oil consumption.

The sensors have a bit of a reputation for being unreliable, but as others have mentioned, always check the harness connections and integrity before spending money.

All engines burn oil. The issue is whether your consumption is excessive. Most manufacturers use one quart in 1k miles as a guideline. Unbelievably, BMW's policy is that one quart in 750 miles is acceptable! They must be having issues with warranty cost! It is necessary to mark the dipstick, keep records and perform an organized test/monitoring before an engine should be pulled apart.

Assuming no porous castings, where does the oil go? The most popular/usual suspects are:
onto the ground,
into the PCV system (intake manifold) and burned in the cylinders,
down the valve guides and burned in the cylinders,
past the piston rings and burned in the cylinders.
Old 11-17-2012, 07:12 PM
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baxsom
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Originally Posted by Tron Z

Assuming no porous castings, where does the oil go? The most popular/usual suspects are:
onto the ground,
into the PCV system (intake manifold) and burned in the cylinders,
down the valve guides and burned in the cylinders,
past the piston rings and burned in the cylinders.
This is the million dollar question.

Catch can is clean. The intake is clean, throttle body is clean, plugs are clean, no smoke at startup, revving either at idle, or while under load on the highway. I pulled the hose from the front of the passengers valve cover to the throttle body off and there was no change at idle. I am thinking at this point I am going to take the rear vacuum caps off of each valve cover and see if a breather will do anything. If I use less, great, if I use more the caps go back on. If there is no change. I spent 10 bucks for nothing.
Old 11-18-2012, 12:21 PM
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Dont want to alarm you but your year is known for having bad rings...

http://forums.corvetteforum.com/c5-g...ngths-etc.html


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Old 11-18-2012, 06:26 PM
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baxsom
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I knew about the ring thing but it doesnt go from using zero oil to using that much. When the car was stock zero oil consumption.

did 04 LS6 valley cover, head and cam and now I am using a quart every couple weeks.

it has to be something in the valley cover/PCV system that wasnt put back together right.


update on the faulty low oil level sender. I drained the oil and put in a new sender today.
no change, The wires look good with no noticeable burn marks from the exhaust but it still gives me low oil as soon as i start it as well as while I am driving down the road.
i filled it with 6.5 quarts of mobil1 and the dipstick reads perfect.

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