Oil Consumption Update (September 2001 update)
Kirk Kohnen
2001:
A few comments:
1) I've not posted this the last few months, but I have kept up with the
data collection. So, a few intermediate oil changes have not been
reported.
2) I did not immediately post the most recent change - that's why this
is the Sept 01 version reported in Oct 01.
3) I'm posting this in two places because there is a oil-burning thread
to which this is pertinent - so it's going there too.
I have a manual '97 SL2 that I bought new. I have been running nothing
but synthetic oil in it (almost exclusively Mobil 1 5w30. A change or 2
using Chevron Supreme full synthetic because it was cheap - $2.50 per
quart on clearance).
My commute is about 75 miles round trip, mostly on So Cal freeways (and
a little surface street driving).
If you want to see previous stuff I've posted regarding this, fire up
dejanews (er, Google - Dejanews was bought out) and look for yourself.
Using a few of the exact mileages listed below as search keys will find
my previous posts for you.
Anyway, here are the raw consumption numbers:
35966 to 39027 miles consumed 30 oz of oil.
39027 to 42088 miles consumed 32 oz of oil.
42088 to 44822 miles consumed 26 oz of oil.
44822 to 47626 miles consumed 35.5 oz of oil.
47626 to 50613 miles consumed 35 oz of oil.
50613 to 53613 miles consumed 32 oz of oil.
53613 to 56674 miles consumed 38 oz of oil.
56674 to 59752 miles consumed 48 oz of oil.
59752 to 62764 miles consumed 44 oz of oil.
62764 to 65578 miles consumed 44 oz of oil.
65578 to 68582 miles consumed 52 oz of oil.
68582 to 71584 miles consumed 56 oz of oil.
71584 to 74499 miles consumed 50 oz of oil.
74499 to 77563 miles consumed 54 oz of oil.
I am modeling oil consumption as a simple linear function of the miles:
Ounces of oil per mile = A + B x Odometer Reading
(for those of you who have been following along in the news group
regarding my oil consumption, this is a slight change from the way that
I have been doing the analysis in the past. It permits me to account
for the slight deviation from exact 3,000 mile change intervals and get
a relatively accurate trend line).
The values of A and B that best fit the measured data are:
A = 0.000236765 ounces per mile (Aware that it's negative - that's how
curve fitting goes)
B = 2.4004E-07 ounces per mile^2
Projecting this data out, at about 65,500 miles (65668 for the anal), I
started consuming 1.5 quarts per 3,000 miles, or 2,000 miles per quart.
This is the point at which Saturn declares that the oil consumption is
excessive.
Editorialization on:
If my numbers (using synthetic oil) are similar to numbers that one
would get with non-synthetic oil, I can see the business model for
Saturn not addressing the oil consumption issue. My engine started
burning excessive amounts of oil (according to Saturn) at about 65,500
miles. I believe that modern engines can, should and do burn much less
oil than this. But, it's hard to stand up and say that an engine that
burns 1 quart every 2,000 miles at 65,500 miles is still in some sort of
manufacturer's warranty - unless of course you spent the big bucks to
get the extended manufacturer's warranty.
Given that I have an engine which has received EXCELLENT care, I think
that starting to consume oil at the rate that its manufacturer declares
excessive at 65,500 miles indicates that my engine has a problem.
I will feed it oil as it needs, but it's clear to me that my Saturn SL2
engine has developed a drinking problem.
Editorialization off:
Before any of you flame me, take a look at the posings that I've made in
this group. Then, if you want, flame away. I think a key point here is
that I'm posting actual data regarding oil consumption. Please remember
that this is a single data point.
Please let me know what you guys think. Posting here or sending me an
e-mail works - either way. And, Saturn, if you're reading this feel
free to contact me - I can give you more details on what I've done if
you're interested.
Oh, and let me save you the trouble: Yes, I'm blissfully aware that I
have no life.
Bryan
FWIW, I am interested in your tracking. For the time being, I've been
spared the problem. But tomorrow is another day!
"Kirk Kohnen" <kkoohh...@attglobal.net> wrote in message
news:3BDB1ED9...@attglobal.net...
Mark S
I did an overall average and got 1 qt / 1100 miles I think it was.
Nothing against you in particular, but I just started going through this
newsgroup a few days ago...what's with all the talk about oil consumption
and how Saturn is going to address it? Why would they address a problem that
'normally' happens out of warranty?
Mark
Miller Gang
anything more than a quart per 3,000 miles is too much. In my humble
opinion, any loss of oil from a modern car is inexcusable.
Have the valve covers ever come off for any reason? (Sorry if this was
already covered, I have not read your other posts.) I once had a Dodge
Caravan that never lost oil at all until the valve cover gaskets were
replaced, then it drank one quart every 1,000 miles thereafter. Dealer
insisted this level of consumption was normal. Didn't need the headache,
traded it in at 55,000 miles (on a Ford).
"Kirk Kohnen" <kkoohh...@attglobal.net> wrote in message
news:3BDB1ED9...@attglobal.net...
Kirk Kohnen
Mark S wrote:
Fire up dejanews (er, google) and look. There is extensive discussion that
covers several years about Saturns and oil consumption.
It is not a short-term topic.
>
>
> Mark
Kirk Kohnen
Miller Gang wrote:
> You don't need to be a genius, a mechanic, or anal retentive to know that
> anything more than a quart per 3,000 miles is too much.
Saturn's official number is 1 quart every 2,000 miles. My car is well past
that rate of consumption.
> In my humble
> opinion, any loss of oil from a modern car is inexcusable.
I would be inclined to agree...
>
>
> Have the valve covers ever come off for any reason? (Sorry if this was
> already covered, I have not read your other posts.)
At about 35,000 miles (somewhere in the 30,000 mile decade) I had the valve
seals replaced. I also replaced the PCV valve, so I think that those have
been ruled out.
When the valve cover was replaced, it was replaced with the factory valve
cover gasket as per the factory specs. It didn't make a detectable change in
oil consumption. I took the old seals to work and looked at them with one of
our special microscopes - they were fine.
Geo
---------------------------------------
1) valve seals replaced
2) new rings
3) new headgasket
4) proper cylinder honing.
If no signs of problems, I'd try running Shell Rotella T 15W-40 oil for 1500
miles... and then Mobil 1 15W-50 for 4000 miles and see if either of these
oils
made the rings or valve guide seals behave better.
As far as 'freeing' up rings.... I might try using an oil rated API CH-4 or
ACEA B398 formulated for diesel engines... like Mobil Delvac 1 synthetic for
4000 miles, or Shell Rotella T conventional oil for 1200 miles.
I'm not a tech nor physic, suspect frozen oil control rings and worn valve
stem guides - the cat is eating the majority of smoke and the remainder is
too dissipated for you to view from your rear view mirror...
----------------------------------------------
Natural Light Black and White Photography
http://www.accesshub.net/geostar/naturalight
-George-
"Kirk Kohnen" <kkoohh...@attglobal.net> wrote in message
news:3BDB1ED9...@attglobal.net...
> Latest chapter in the ongoing saga of my '97 SL2, updated 20 September
> 2001:
>
> A few comments:
>
> 1) I've not posted this the last few months, but I have kept up with the
> data collection. So, a few intermediate oil changes have not been
> reported.
>
> 2) I did not immediately post the most recent change - that's why this
> is the Sept 01 version reported in Oct 01.
>
> 3) I'm posting this in two places because there is a oil-burning thread
> to which this is pertinent - so it's going there too.
>
> I have a manual '97 SL2 that I bought new. I have been running nothing
> but synthetic oil in it (almost exclusively Mobil 1 5w30. A change or 2
>
> using Chevron Supreme full synthetic because it was cheap - $2.50 per
> quart on clearance).
>
> My commute is about 75 miles round trip, mostly on So Cal freeways (and
> a little surface street driving).
>
> If you want to see previous stuff I've posted regarding this, fire up
> dejanews (er, Google - Dejanews was bought out) and look for yourself.
> Using a few of the exact mileages listed below as search keys will find
> my previous posts for you.
>
> Anyway, here are the raw consumption numbers:
[EDITED]
Kirk Kohnen
Geo wrote:
> Here's something I saved from a while back. Have you tried this?
>
> ---------------------------------------
> 1) valve seals replaced
They were. No change. Look at other posts that I have provided - this is a
long-term set of posts for the newsgroup's benefit.
>
> 2) new rings
> 3) new headgasket
> 4) proper cylinder honing.
>
> If no signs of problems, I'd try running Shell Rotella T 15W-40 oil for 1500
> miles... and then Mobil 1 15W-50 for 4000 miles and see if either of these
> oils
> made the rings or valve guide seals behave better.
>
> As far as 'freeing' up rings.... I might try using an oil rated API CH-4 or
> ACEA B398 formulated for diesel engines... like Mobil Delvac 1 synthetic for
> 4000 miles, or Shell Rotella T conventional oil for 1200 miles.
I don't think that it is a set of "frozen rings," as I would not think that the
oil consumption would increase so slowly & consistently.
Also, I don't think that it's worn valve guides, as replacing the SEALS did not
make a difference.
If the valve guides were out, replacing the seals would result in a dramatic yet
short lived reduction in the oil consumption.