: Carbon knock and 1 quart per 1.000 miles



FrankT
03-20-04, 06:18 PM
Hi all I own a 99 sts that has a cold knock only and sighlty oil consumpsion problem. I am very hesistant to let the dealer open up my northstar engine. Has anybody out there had pistons and rings installed by the dealer under warrenty? If so do you have any regrets?
Thanks,:suspect:
Frank

growe3
03-20-04, 09:24 PM
It sounds like you do not "exercise" the engine enough to keep the rings loose and this also tends to allow carbon to build up in the combustion chamber.

When you get on the freeway floor it up to at least 65 MPH (or higher conditions allowing).

When getting off the freway downshift and let the engine braking slow you, it will tend to flutter the rings and keep them loose. This should be at least a daily routine to keep the engine loose.

Do not overfill with oil, this can cause the engine to actually use more oil. Normal complete fill is 7 1/2 qts (not 8). Check the dipstick when HOT, the oil should be about halfway into the indexed area. When it doesn't touch the dipstick any more add as needed to bring it back up.

-George

BeelzeBob
03-21-04, 01:37 AM
Hi all I own a 99 sts that has a cold knock only and sighlty oil consumpsion problem. I am very hesistant to let the dealer open up my northstar engine. Has anybody out there had pistons and rings installed by the dealer under warrenty? If so do you have any regrets?
Thanks,:suspect:
Frank

You don't need pistons or anything....quit driving it like a weenie and open it up...frequently. Just a few WOT accels will clean the carbon out of the chambers and eliminate the cold carbon rap....and it will start to exercise the rings and reduce the oil consumption. The motor was designed to be run hard often and does not like to be grandma'd around. Flog it regularily.

Go to the search feature and search on "oil consumption" and read up. Lots of info there.

FrankT
03-27-04, 02:54 PM
George, bbobnyski,
I have been ripping on my northstar after reading your post and the carbon knock is gone. I will let you know about the oil consumption after an oil change and recheck. I am expecting less than 1 quart per 1k, from the sounds of it 1 quart per 1k is normal for the northstar. I taking it easy before and when I did get on it there was always a cloud of black somke. Now it gone when I do a WOT.
Thanks,
Frank

BeelzeBob
03-27-04, 10:22 PM
George, bbobnyski,
I have been ripping on my northstar after reading your post and the carbon knock is gone. I will let you know about the oil consumption after an oil change and recheck. I am expecting less than 1 quart per 1k, from the sounds of it 1 quart per 1k is normal for the northstar. I taking it easy before and when I did get on it there was always a cloud of black somke. Now it gone when I do a WOT.
Thanks,
Frank


Good.... we'll make a believer out of you yet. It likes to be run hard and often so keep at it.

wake
03-28-04, 02:39 AM
Good.... we'll make a believer out of you yet. It likes to be run hard and often so keep at it.
One thing that helped with my oil consumption was running it 1/2 quart low... I drive my Northstar very hard which keeps the carbon knock away, but I still burned lots of oil it seems...

Now I add 7qts instead of 7.5qts at the change, and I add 1/2 quart when the, "Check Oil Level" message apepars... This method seems to have cut my consumption in half over the last 2 years...

It just seems that at least on my car, using the recommended fill level, I burn through the first 1/2 quart of oil pretty quickly...

Olds3.5
03-29-04, 11:19 PM
It is indeed a wonderful thing that we now know how to exorcise the oil consumption demon by exercising the rings. However, I do not believe it is a weenie problem since such a large percentage of the consumers of Cadillacs typically drive way below the design potential of this engine.

I bought my car from Avis rental car and never had an oil consumption issue. My engine holds six quarts and consumes about one quart per 4k miles. Obviously it was run pretty hard by some Avis customers.

I am surprised that the ring design of the 4.6L was not modified to match the break-in driving habits of the consumer. The demographics of the deville might be a pretty good match for a weenie. Something like a reputation for oil consumption suggests that the engine is wearing out prematurely, which is not true in this case. My brother has owned and operated an automotive shop for over 25 years and the first thing to come out of his mouth when I asked him about the N* was "they burn oil".

BeelzeBob
03-29-04, 11:25 PM
It isn't the break in habits as much as the long term driving habits. I guess the thought was that it was a performance engine and was optimized for that...and the assumption was that people would use the performance....no one realized just how badly some customers could baby the engine I guess....LOL

YOu are right that the perception of oil usage does tend to make people think of the engine wearing out. As evidenced by the excellent condition of the engines that have been dissassembled on this forum with well over 100K on them the engine does not "wear out...". There are engines that have over 250K on them that the original honing marks are still visible in the cylinder bores. The down side is that to get this the engine consumes some more oil by design and that there is considerable variability in the oil consumption. To the engineers that developed the engine the oil consumption just wasn't as high a priority as it is to consumers. Consumers just cannot accept the fact that some oil consumption is good.....

bolvey.1
05-18-04, 07:19 PM
Hello Bbob,
I fell in love with and bought a 96 SLS from the family of an 86 year young women.
My first Caddy.
The car had not been driven the last 2 years and had 36,480 miles.
I'm using a quart of oil at about 800 miles.
I do mostly hiway driving and have put about 3000 miles on it so far.
You don't have to ask me twice to flog it on the hiway, it flys!
Will oil consumption improve with flogging or should I have the dealer chemically do a carbon removal for the rings?
What kind of oil do you recomend?
Thanks!
Mark