89 Caravan: Will engine clatter if Oil Pressure is Low?

Hi, gang:

The oil pressure gauge in my 89 Caravan 3.0 has been reading goofy
(and generally lower than I'd like) for a few months, now. The whole
mess seemed to be triggered by a local shop that put 5W-30 into the
engine during an oil change, when I've been running 10W-30 or 10W-40
for years. Before that oil change, no issues with the oil pressure
gauge AT ALL. After the change, on the same day, I noticed that the
pressure reading dropped when I was cornering at very low speeds. I
can't prove it, but the coincidence seems odd. Fine for five years,
then goofy starting 15 minutes after the oil change in question...

Sometimes, when I come to a stop after the engine's warm, the oil
pressure gauge will plunge. It doesn't do this when it's cold -- and
in Minnesota, it's COLD!

Last night, when I drove to work, about 6 blocks before I arrived, the
oil pressure gauge dropped to nothing. As I was slowly driving the
rest of the way, the needle would occasionally climb up a bit, then
drop off to nothing again (triggering the "check gauges" light on the
dash).

After work I topped off the oil (half-a quart below full) and fired up
the beast. As it has been for the past few months, it started and ran
fine, despite the fact that there was now NO READING from the OP gauge
at all. I drove home 10 miles at 30-40 MPH, got home and parked, and
listened to the engine. It was smooth-sounding and seemed to be
running just fine (as it had all the way home).

QUESTION: If there truly was no oil pressure, wouldn't the engine
start to clatter?

I hope like hell it's the sending unit. I'm trying to find a buddy
with a manual pressure gauge...but I have to drive back to work in the
morning.

Any ideas?

Thanks, as always,

--Kirk in MN

P.S. It really sucks working on the car when the wind chill is 40
below zero...

 

Stop dealing to long with this because a sufficient oil pressure is the most
important in your engine more important then fuel. Check for the OP sending
unit and make an OP check with an attached external gauge.

Regards,

Ralf

 

Ralf is exactly right. Probably a defective sending unit, but you need
the pressure read with a real gage. Then, when you find out the
pressure is higher than the sender is saying, replace the sender and
quit worrying about it.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Oil pressure is pretty serious. I would have resolved the issue immediately
with no further driving. If you do have a problem, you've likely taken
years off the engine. An engine will only last a few weeks with a bad oil
pump.

The sender is near the oil filter. It sounds like they may have broken it
during the change. Go back to the oil change place and try to have them, at
least, install one you bring in from the parts store. Should be very easy
for them to do.

 

Probably is, but do what others have said and CHECK.

If the pressure tests low, don't give up just yet. Try changing the oil
FILTER. If the shop put on a cheap filter that has partially collapsed
internally, it could be the cause of your low oil pressure.