Okay, here's my current predicament...
I was enroute to NY from Boston on Fri, when I noticed that my oil pressure
has dipped. Here's the scoop:
-I had always, up to this point, gotten ~50pso at idle and ~90psi at highway
speed. Now, suddenly, I was getting 55-60psi at highway and ~20psi at idle.
Horrified, I pulled off. :-) I checked the oil-nothing. Still full up; no oil
visible around the engine (at least, no more than normal.) The radiator was
still full. When I slowed down to get off the highway, my temp shot up, but
because I was worried I can't tell if it did it faster than it normally does
when I slow down from cruise to stop&go traffic (for tollbooth, eg). So, I
put a quart of 20w50 in her just to be sure, and set off again. This time, I got
around 25psi at idle and 60-70psi highway. At speed, the car ran at normal temp
or perhaps a bit cooler. I proceeded to NYC, since I was more than halfway there
anyhow. The car appeared to behave fairly normal; although it may have heated
up at slow speed a bit faster when the pressure was down around 25psi.
As long as I had anything over 1750rpm, I had opver 50psi pressure; the gauge
acted just as if I had shifted my noraml operating range down by 20psi.
Here are my ideas, as a tyro TR6 engine person:
1) Oil breakdown. I had been pushing it a little hard for about an hour prior
to the drop being noticed, although the temp hadn't gone over halfway through
the normal range. I reason this because when I put a quart of fresh oil in
pressure went up slightly, although just the added volume might have done
this.
2) Oil Pressure sending unit gone bad...small leak through sensor?
3) Oil pump going. Engine sounded dead normal all the way; but maybe the pump
is in trouble?
4) Dropped the thrust washers...I remember someone saying that this was
accompanied by a drop in oil pressure, but can't remember how much. I would
think more than 20psi, though.
5) Did someone speak earlier of a pressure relief valve? I used to get right
up around 90psi pressure at speed, and I was pushing it...could I have
tripped some kind of valve that lowered my pressure?
Anyhow, I have to drive back to Boston because the only mechanics I trust are
there...but I'd love to hear any input folks on the net may have. I was think-
ing of getting an oil change before going, just in case it is something as
simple as oil breakdown (the oil's only around 2500miles old, though.)
So, <in trepidation> any ideas, all? Thanks for your ideas. :-) :-(
-JBZimmerman and Amanda in NYC...with 200 miles ahead of them.
|