02 Buick Century, Pennzoil Ultra 5w30, 6125 mi

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Here is my 2nd UOA from my 2002 Buick Century in service for 6,125 miles but much less idle time than last sample since I pulled it before winter set in. This is Pennzoil Ultra 5w30 the older API SN Formula not pure plus. In service for 8 months. My Flashpoint is exactly the same as previous fill of Pennzoil Platinum so it's getting good and hot even though it's heavily short tripped. TBN isn't as high as I'd hoped for Pennzoil Ultra but it's not awful. I had them run both the old and new method for TBN. Funny this car is specified with 7500 mile intervals with API SL oil, I'd hate to see the TBN on conventional SL after 7500+. Looks like I have an intake leak somewhere and it's effecting my bearing wear significantly. Going to have to re check that area again, it's a pain on these cars, no room to wiggle the intake around. Will be running conventional oil for 3k intervals for a while until I get this sorted out. Might even dump my Fram Ultra early to remove the half a quart of contaminated oil from the system. Oil filter used on this sample is Fram Ultra XG 3980 with a filter mag oversized from the 3387A so I was able to dump the whole 5.1 quart jug of PU into this fill. Currently re filled with only 4 quarts of peak conventional 5w30 since I left the filter on with only 6k miles on it. Air filter is a Purolator PureOne installed right after I changed the oil on the first sample so it has 12k miles on it, but it's getting past it somewhere, I'm going to check the seal this weekend and possibly replace it out right with a paper filter just to eliminate a variable.
 
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Lower intake manifold may be leaking. Evey GM V6 that I know(friends and family) of has leaked at the LIM.
 
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Originally Posted By: tig1
Lower intake manifold may be leaking. Evey GM V6 that I know(friends and family) of has leaked at the LIM.
He is at the mileage they like to fail, however his sodium shows a normal level.
 
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This is the 3.1, right? The silicon and lead levels are much, much higher than the samples I've taken in a 2003 Malibu with that engine. Hopefully you're able to get to the bottom of this.
 

901Memphis

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Originally Posted By: ThirdeYe
This is the 3.1, right? The silicon and lead levels are much, much higher than the samples I've taken in a 2003 Malibu with that engine. Hopefully you're able to get to the bottom of this.
Yes the 3.1. I am hoping the issue is the silicon and is correctable to get the numbers down if i can find a source of un filtered air getting into the engine.
 
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I would scan the fuel trims. That would point if there was a vacuum leak. If no leak is found I'd run a 4k interval. I'd bet there's definitely a leak.
 

901Memphis

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Originally Posted By: 97 GTP
I would scan the fuel trims. That would point if there was a vacuum leak. If no leak is found I'd run a 4k interval. I'd bet there's definitely a leak.
I do get very poor gas mileage about 15 mpg but thought it was related to the P0420 code.
 
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Originally Posted By: 901Memphis
Originally Posted By: 97 GTP
I would scan the fuel trims. That would point if there was a vacuum leak. If no leak is found I'd run a 4k interval. I'd bet there's definitely a leak.
I do get very poor gas mileage about 15 mpg but thought it was related to the P0420 code.
It should get better than that. My 93 olds with the 3300 ( 3.3 three speed) gets better than that. I have undersized tires and i still get 20 town and 25 hwy. With correct tires i get 29 hwy. Perhaps the upstream o2 sensor is slow.
 
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901Memphis

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Originally Posted By: spasm3
Originally Posted By: 901Memphis
Originally Posted By: 97 GTP
I would scan the fuel trims. That would point if there was a vacuum leak. If no leak is found I'd run a 4k interval. I'd bet there's definitely a leak.
I do get very poor gas mileage about 15 mpg but thought it was related to the P0420 code.
It should get better than that. My 93 olds with the 3300 ( 3.3 three speed) gets better than that. I have undersized tires and i still get 20 town and 25 hwy. With correct tires i get 29 hwy. Perhaps the upstream o2 sensor is slow.
Yeah i am sure it needs a lot of stuff, but wasn't sure where to throw the money at. It has oversized tires, not sure if that is hurting the mileage, i use the stock size from the Regal, since i got a set of rims/tires off a regal and kept it that way.
 

901Memphis

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Wonder how much a shop would charge to change the o2 sensor? Not sure if i could get to that myself, as old as they are... Should i go for both of them or one in particular?
 
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15mpg. Ouch. My 6.0 c3 gets 15mpg in the city and 22 or so on the highway if no headwind. And my charger has never gotten mileage that low,well except at 140mph. Get it fixed. Think of the costs involved. A few hundred bucks to gain double the mileage and longer oil change intervals means do ending on how much you drive you could recoup the expenditure in a month or 2,depending on how much you drive. If you don't drive much it may not be worth fixing.
 

901Memphis

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Well if my wife drives she gets 17 mpg. It does much better on the highway though, not sure i don't take many high way trips anymore.
 
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