89 Caravan: Oil pressure plunges when I turn corner at low speed - HELP!

Hi, gang:

I have an 89 Grand Caravan I've been nursing along for a few years.
Great chassis and body, but it's on the third tranny and second
engine. Van has 204,000 overall, with about 120,000 on present 3.0
liter engine.

Oil pressure has been fine for the past year. I just had the oil
changed at a local garage, however, and they used 5W30 oil, where I
have always used 10W40.

I noticed that, after the switch, that the oil pressure gauge would
read somewhat lower than usual when the engine was hot...and after
three weeks or so, the gauge started reading VERY low at idle when
warm.

Today, on the way home from work, when I was coasting up to a corner
at 10 MPH or so, the oil pressure plunged to zero as I turned the
corner to the left. It did the same thing when I hit the brakes while
coasting at low speed.

If I hit the gas a bit, the pressure perked up, but never came close
to where it used to read (half scale or slightly greater).

I thought I might be low on oil, but when I checked it, it was okay.

The engine never made any clicks or clattering noises during the low-
pressure events, but it can't be a good sign....

1. Will changing to a thicker oil help?
2. Is the oil pump gone bonkers? If so, is it worth replacing?
3. Bad sending unit?

Did I mention that, while intelligent and good looking, I'm in a
severe poverty phase at the moment? And that if the solution costs
more than a measly, moderate amount, I'll be walking?

Any ideas will be greatly appreciated.

Thanks,

--KK in MN

 

If not low oil or tramp stuff in sump, it may be a loose electrical
connection.

 

Aside from it likely being a problem with the gauge/gauge wiring (based on
your statement that the oil level was okay and that there were no funky
noises from the engine, you probably should go back to heavier oil for such
an old critter. Better yet, add some MoS2 (molybdenum disulphide) with every
oil change. Aside from improving lubricity, it plates out under heat &
pressure on things like bearings, rings, etc., thereby reducing gaps from
wear (and so reducing oil usage) and improving oil pressure.

 

Group:

It's not a loose connection. I checked.

Further, when the engine is cold, oil pressure is good, and no amount
of cornering or braking seems to affect the oil pressure.

--KK in MN

 

Uh oh, I hate to tell you this, but...

I had an older Daytona that caught something on the highway and it put a
small hole in the oilpan. I saw the puddle before it did any damage. So I
topped off the oil and took it to a garage. Turned out the oil pan wasn't
readily available. The car sat for 5 days till they gave up. They pulled
the
car in, took off the old oil pan, cleaned it, welded it, and put it back.

Only when I got the car back it did the same thing you describe.

Now, I can't PROVE anything, but what I think they did is let the car
sit for 5 days and the oil drained totally out. Then they started it and
drove it into the bay with no oil in it...

 

What engine is in this 89 caravan? Sorry if you posted this info, but I
missed it.

 

In that case, it's the oil pump OR the main bearings are shot.

 

Given those additional facts, I'd say worn main bearings, or possibly
the oil pump.

 

Oil pump or worn main bearings (most likely). Buy some time with a
heavier weight oil or do a teardown & rebuild.