1990 Pontiac Bonneville with 3800 engine.
After driving several hours,
pulled into traffic and wound the engine up a little to about 3000 rpm
maybe. Noticed the oil light on and no pressure on the gauge. Shut it
down checked the oil etc. Started it back up and didn't hear any
rattling or clanking. Revved it up to around 2000 rpm and the oil
light would just go out and the gauge would just move. I had just had
the pressure sender replaced before we left so I thought it was
probably a bad sender again. Drove it home with the oil light on all
the way, about 100 miles in the sticks. Took it to a garage at home
and he put a regular gauge on it and found about 3 lbs at idle and
about 15 lbs at 2000 rpm. Normal pressure should be around 40 lbs.

The 3 lbs. and 15 lbs. oil pressure was with the engine not fully
warmed up.
Before this happened the pressure gauge would be right at mid scale
when running on the highway and not drop at all at idle. After it
warmed up well the gauge would show a little below midway at highway
speeds and drop slightly at idle.

The sudden drop to 3 lbs happened all at once. The car has only 60
thousand miles on it and the oil was just changed a few hundred miles
ago.

Any thoughts where to start looking?

Thanks!
Gary

"Gary Schafer" <gaschafer (AT) comcast (DOT) net> wrote

I'd say you're pretty well going to have to look at the bottom end bearings
and the oil pump. Sometimes it just doesn't take much to wreck one.

I've heard of oil filters causing problems like this. It wouldn't take much
to try a new one of good quality.


"Joe" <Joe (AT) dontspam (DOT) net> wrote

well my bet is on the bearings are shot

"Scott Buchanan" <t120rv (AT) pacifier (DOT) com> wrote

The first thing I did when I got back was to put another new oil
filter on. No difference.

Thanks
Gary

On Thu, 4 Jan 2007 20:58:07 -0800, "Scott Buchanan"
<t120rv (AT) pacifier (DOT) com> wrote:

On Thu, 04 Jan 2007 22:45:33 -1000, Geoff Welsh
<geoffdubya (AT) some (DOT) rr.com> wrote:


It has only 60,000 miles and the car is in excellent shape but for the
oil pressure problem.

I don't think it is worth a new engine though at that age.

Thanks
Gary

Assuming you had decent oil in it and drove it home "carefully" (no
heavy acceleration, no high rpm, etc) then there's a pretty good chance that
nothing got hurt.
If it were mine, I would send an oil sample in for analysis before I
spent any time or money trying to fix the oil pressure problem. If the oil
analysis comes back without a lot of bearing material... you probably got
away with it.
In that case, just fix the oil pressure problem (probably a relief spring
in the filter adaptor) and rock on. Perhaps have another analysis done at
the next oil change to confirm that nothing is "coming apart" on you.
I found this on another site,

"Titan has an "Engine Oil Analysis" kit sold at AutoZone stores. Ask for the
"PPM" analysis instead of the standard "ABC" analysis as it is more
detailed. Look for high silicon levels, wear metals, low TBN (reduced oil
viscosity), and engine oil contamination, especially excessive fuel and
glycol presence (sodium and potassium elevation). Connect with other owners
to compare results. Do several analyses over time to show the changes."

There is info on the Titan kit at the bottom of this page, in case you
don't have an AutoZone nearby: http://s2.pegasusautoracing.com/2006/066.pdf





"Gary Schafer" <gaschafer (AT) comcast (DOT) net> wrote

Titan Lab website:
http://www.titanlab.com/content/insi...ducts/Oil.html



http://pstuning.com/ "David Courtney" <advance (AT) powercom (DOT) net> wrote in
message news:507cjnF1enpheU1 (AT) mid (DOT) individual.net...

On Fri, 05 Jan 2007 22:57:04 -1000, Geoff Welsh
<geoffdubya (AT) some (DOT) rr.com> wrote:

No, I guess I am the second owner. Just got it this summer from some
older people that went to a nursing home. I didn't get to drive it but
a few hundered miles before the oil pressure problem. It ran fine and
worked well when I got it.

Gary

Well from what you are describing it sounds like the oil pump is blocked up
or broken. I would bet that the bearing are shot too if the pressure drops
to zero. From personal experience, if the car is not all rusted out, I would
go buy a long block, pull the engine, and start with the new long block.
Take all the parts off your old engine that you need to complete the install
and have a new engine to drive with.

"Gary Schafer" <gaschafer (AT) comcast (DOT) net> wrote