Oil to combat consumption?

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I recently purchased a '00 Bonneville with the supercharged 3800 engine. Besides a tune-up and a host of other preventative maintenance, I changed the oil right off the bat at 106k mi with Pennzoil Ultra 5w30 and a German Bosch filter.

Fast forward 3k miles, and I'm one quart low at my last fillup. OLM in vehicle reads 50% life remaining. Though this rate of consuption is not terribly alarming, I've not had a vehicle in years require any top-off oil in between changes, so it has me concerned. No drips on the ground or oil stains in the obvious places, so I can only assume it's burning the oil.

Any history of these engines burning oil? I'd like to minimize it if possible, are there any oils known for their resistance to burn off? Would a thicker grade help, perhaps switch to conventional? Input and suggestions would be appreciated. I'd like to run 7500-10000 mi OCI's if possible; GC 0w30 would have been my next fill until I discovered this.
 
Congrats on your purchase! A new (to you) car is always fun.

The only brand I know of that reduces consumption fairly reliably is Renewable Lubricants (a.k.a. RLI).

Thicker oil may or may not help, depending on what is causing your consumption.

All that said, don't be so hasty to switch. You just put the Pennzoil Ultra in, so consumption might settle out after a few OCIs. IMO, keep running exactly the same oil for 2-3 OCIs and revisit the issue then.
 
Also 1 quart in 3K is not any thing to be worried about. A good rule of thumb is any less that 1 quart per 1K miles is fine. But it is common that when switching an engine to a new oil that it will consume more than usual for the first couple of OCI's.
 
I've had good luck with Pennzoil High Mileage in my sons saturn. When he goes to college the first year, it will sit a lot so i will put mobil ep in it. The Pennzoil High Mileage dropped oil usage from a quart in 200o miles with maxlife to 1/2 in 2000.

Bryan
 
Originally Posted By: dave1251
Also 1 quart in 3K is not any thing to be worried about. A good rule of thumb is any less that 1 quart per 1K miles is fine. But it is common that when switching an engine to a new oil that it will consume more than usual for the first couple of OCI's.


I hear this pretty often but where is the proof?
 
The synthetics are designed to burn off more slowly then conventional oils. Some do a better job then others. My old 1985 Chevy Caprice with 305 4bbl. used 1 qt of 10w30 GTX in 1200 miles. 1 qt of Syntec every 2000 miles. 1 QT of Amsoil in 3000 miles. Point being on conventional oil your Bonneville my have used 1 QT of conventional oil in 1500 miles instead of 1 QT of Ultimate in 3000 miles.
 
Originally Posted By: RamFan
Originally Posted By: dave1251
Also 1 quart in 3K is not any thing to be worried about. A good rule of thumb is any less that 1 quart per 1K miles is fine. But it is common that when switching an engine to a new oil that it will consume more than usual for the first couple of OCI's.


I hear this pretty often but where is the proof?


My wife's Toyota Yaris says in the owner's manual, and I quote: "Oil consumption: Max. 1.0 L per 1000
km (1.1 qts./600 miles, 0.9 lmp.qts./600
miles)"

...so it seems that Toyota is unconcerned until oil consumption gets greater than 1.1 quarts per 600 miles.
 
Trying to lower oil use can be a challenge especially W/O knowing what is causing the oil use. EG: If it is the rings, a thinner oil can actually help. Valve seals, and guides going to a thicker oil can help. My Aerostar uses some oil, switching from a 5W30 to a 5W20 helped. I'm now trying a 5W40, since I bought a lot of it for a very good price. I have some slight leaks I'm going to see if a 40 grade helps. I've never used it in this vehicle.
 
Originally Posted By: ChuckBerry
Originally Posted By: RamFan
Originally Posted By: dave1251
Also 1 quart in 3K is not any thing to be worried about. A good rule of thumb is any less that 1 quart per 1K miles is fine. But it is common that when switching an engine to a new oil that it will consume more than usual for the first couple of OCI's.


I hear this pretty often but where is the proof?


My wife's Toyota Yaris says in the owner's manual, and I quote: "Oil consumption: Max. 1.0 L per 1000
km (1.1 qts./600 miles, 0.9 lmp.qts./600
miles)"

...so it seems that Toyota is unconcerned until oil consumption gets greater than 1.1 quarts per 600 miles.


Sorry I should has specified what I was questioning, I meant that I hear people say that switching to a new oil will burn more for the first couple of OCIs and that oil consumption will slow after a couple OCIs. With that theory, the way most BITOGers switch oils I would think that everyone would be complaining about oil consumption.
 
I would go with Mobil 1 5w30 High Mileage. If you have ring coking this oil may help over several OCIs to clean up this problem. Also HM will help with burn off as it resist heat burn off. Just a thought.
 
I tried 10/30 Edge in my 3.8 Bonneville. It was on sale so I bought enough for 2 OC's. Consumption was high, so I went back to random (Rotella T5/Maxlife/Cheap stuff). Consumption has always been high with this car, but I can afford the 1 Qt every 2000 miles or so. It has 220K on it, now.
 
Originally Posted By: RamFan
Sorry I should has specified what I was questioning, I meant that I hear people say that switching to a new oil will burn more for the first couple of OCIs and that oil consumption will slow after a couple OCIs. With that theory, the way most BITOGers switch oils I would think that everyone would be complaining about oil consumption.


When changing brands it is a good idea to use the same brand/grade for 2-3 OCI to see if consumption increases or decreases. It is not uncommon to use more oil when changing brands.
 
Originally Posted By: RamFan
Sorry I should has specified what I was questioning, I meant that I hear people say that switching to a new oil will burn more for the first couple of OCIs and that oil consumption will slow after a couple OCIs. With that theory, the way most BITOGers switch oils I would think that everyone would be complaining about oil consumption.

It's not that switching oils WILL cause consumption to spike; it's that it COULD do it. My understanding is that it's a fairly rare thing and depends on the formulation.

As for the source, I can only speak for myself; I'm mostly taking it on authority, which I feel okay doing because I've seen it happen in two different cases (Motul 300V 5w-40 in my car and RLI BioSyn 0w30 in my brother's car).
 
Originally Posted By: RamFan
Originally Posted By: dave1251
Also 1 quart in 3K is not any thing to be worried about. A good rule of thumb is any less that 1 quart per 1K miles is fine. But it is common that when switching an engine to a new oil that it will consume more than usual for the first couple of OCI's.


I hear this pretty often but where is the proof?


Define "proof"?

I know that my car never had any noticeable consumption (say more the 1-2mm on the dipstick) over the course of an OCI, and both times I changed brands, it consumed oil on the initial OCI with the new oil, and a little more on the second run. By the 3rd run, it went back to consuming no noticeable oil.

This isn't some sort of well-controlled experiment, it's simply my observation. Others have observed the same thing, so I think the recommendation to give it a couple of OCI's is reasonable.

I have absolutely no understanding as to the mechanism by which this occurs, but it's my own observation nonetheless.
 
An engine is a piece of metal with clearances. I can't see how or why it would take 2 or 3 oci to see a difference. I could run dino in my Caprice,use a Qt in a 1000 miles and swap to Amsoil and immediately it was 3k between Qts. I have horses and it takes a while to see a difference in them when feed is changed LOL but not a internal combustion engine. Same with OCTANE 87 to 93 in my vette is a noticeable difference within a few miles of fill up.
 
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