Increased Consumption GM 3800

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Jul 30, 2006
I have a 99 Chevy Camaro with the GM 3.8 V6. Up to 70,000 miles the car hardly used any oil at all between changes. I have typically changed the oil using the oil change light, which for my driving conditions comes on at about 4500 miles. I have owned the car since new, used only Pennzoil dino 10W-30, and done all the maintenance on schedule. During my last oil change interval, the car started using oil. It used none at 2000 miles, 1/3 quart at 3000, and 1 full quart by 4,000. I swtitched to Castrol GTX from Pennzoil and changed my PCV valve to see if that would help. Instead it got worse, now it used 1/4 quart at 1000 miles, 2/3 by 2000, and a full quart by 3000. This time I got nervous and changed the oil at 3000 instead of adding. Usually these engines are bulletproof and don't have this problem. I am looking for advice on what to use to reduce this consumption, or to find out if anything is wrong that needs attention. Thanks.
I never had any problems with my 3800 on 5 or 10-30, but the UOA's tend to lean towards 40's I think, take a look around before believing it though. I agree with batman though, try 4 qts of your preference, and some HDEO or other cheap 40 weight. You could also look into a catch can. They seem to help out the LS1 people reduce oil consumption down the intake, and it would help you figure out if the PCV is what is drinking the oil. How does the intake manifold look.
The intake looks pretty clean. I thought a new PCV valve would help but it didn't. So it seems a good solution might be to add half a quart or so of 10W-40 each change. I'll give that a try...since I just changed it, when it burns some I can use some 10W-40 as make up oil this time around. What about high mileage oils? Someone suggested that to me as well.
Check oil pan for leaks and check the oil sender for leaks. It is unlikely that it would just suddenly start useing oil! The alternative is that the new oil does not agree with the engine.
Since you are tripping the oil change light at 4500miles, your driving has probably coked the 10W-30 dino on the rings. Clean the rings through ARX or other means, then run top tier 5W-30 synthetic oil from here on out. It is easily worth the extra cost for the synthetic oil in your application.
While that doesn't seem bad, I would look for a leak rather then burning. Evem my 250k mile 3800 doesn't use more then 1/2 quart in 3000 miles. Take a good look at the oil pan and valve cover gaskets.
It is not visibly leaking oil at all. The oil pan is dry as a bone, but the valve covers are a little moist around gaskets. Still, it is only a faint stain and no visibly flowing oil. The engine bay is very clean, so it's unlikely that I would use that much oil from leaks. Also, it started using with the Pennzoil, I tried Castrol just to see, but it began before I changed the brand. I drive a lot of short trips. My driving is about 75% city, on trips that are 15 minutes or less. So I am leaning toward the sticky rings theory given the situation. I used to drive the car on the highway regularly, but in the last couple years the situation has changed to mostly city. That may have had an impact on the rings. So...current suggestions are add some 10W-40, use high mileage oil (perhaps 10W-40), or clean the rings with ARX or something similar and switch to synthetic. I doubt I will swtich to synthetic, if anything, I would use dino and change more often. Also, the engine specifically calls for 10W-30 so I won't use 5W-30 either. We are talking about a GM 3.8 and they can run forever on dino with no issue according to my research.
Originally posted by camarodude: Also, the engine specifically calls for 10W-30 so I won't use 5W-30 either. We are talking about a GM 3.8 and they can run forever on dino with no issue according to my research.
I know that it specifies 10W-30, but I'm telling you, my Buick with the 3800 picked up a lot of fuel mileage switching to MaxLife 10W-40. The oil GM specifies is for a brand new tight engine. When things loosen up after awhile, they need just a tad thicker oil to fill the space.
Clyde, I agree. When I mentioned that the engine calls for 10W-30 I was referring to the suggestion to use 5W-30 after an ARX treatment which I do not agree with. Given your specific experiene with the 3800 I am going to follow your recommendation. Thanks.
Make sure the PCV is a AC delco one. I have 131k on my L67 and use about a 1/2qt in 5k miles.
I put in a Fram PCV valve, same as the last one. That's all the parts store had in stock. Does it really make a difference?
I have heard it does sometime makes a difference if the weight/spring tension is different in can suck in oil. I just clean mine once it a while and it's still the original PCV.
A Fram PCV valve was causing rough idle on my 3800. When I went back to AC Delco, the problem stopped. I'd recommend an OE part in this case.
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