Oil Pressure - 88 Caravan 3.0L 184,000 miles

Greetings,

My oil pressure gauge has been reading dangerously low within 3-4 minutes of a cold start. The needle borders the caution zone at idle and has a tendency to dip into this zone under acceleration. First couple of minutes it will read fine, but the minute the oil warms up the pressure dives. Before this started occurring, I had noted a few random occurrences where the gauge flatlined when accelerating hard (2.8-3K rpm) from a stop as if it wasn't reading at all. During these instances, I would immediately back off the throttle and it would return to normal.

There is a noticeable ticking and given the mileage I would expect some wear to be part of the cause of a low pressure reading. I've also run some engine flush through it to help clean out any sludge in the oil pick-up screen. Looking through the archives, I've noted that replacing the oil sending unit seems to be a fairly common task for those with low pressure readings. Where exactly is this located and what is involved in replacing it? Several old posts state that it is near the oil filter, but the autozone web site states that it is located _inside_ the oil filter adapter. There is no reference to it at all in my Haynes manual. I'm also curious, is this unit simply a sensor for the gauges?

Aside from the sending unit, are there any other possible causes for these readings? I assume the pump is fine as the readings are normal to start. FWIW - I'm running Mobile One Syn 0W-40 and a Purolator Plus filter.

Thank You,

-Paul

Reply to
Paul A Gigl Jr
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typical symptoms of a worn oil pump.

Ted

Reply to
Ted Mittelstaedt

Correct diagnostic procedure is to connect an external oil pressure gauge to the engine, usually where the sending unit screws in, and take an *accurate* measurement of the oil pressure and then compare what you get to the spec in the FSM. If the pressure is okay, you've got a sending unit problem. If not, you have engine wear: could be bearings, oil pump, or a clogged pickup tube.

Anything else is a waste of time, effort and money.

--Geoff

Reply to
Geoff

That's pretty characteristic of a bad oil pressure sending unit with a "dead spot" as the pressure swings through a certain zone. Certainly it would be the first thing I'd check- with a mechanical guage hooked up instead of the factory electrical guage.

Other possible causes range from simple (collapsed oil filter- hope you're not using a Fram :-) to severe (bearing clearances opening up so wide that the crankshaft shifts under heavy acceleration.).

Start little, hope for the best.

Reply to
Steve

Or better yet, stay with Mobil 1, but use the recommended viscosity from your owner's manual and find out what is really wrong with your engine. It is crazy to switch from an outstanding oil like Mobil 1 to a run of the mill oil like Pennzoil.

Matt

Reply to
Matthew S. Whiting

Dump that rubbish and install Penzoil

Unless the cheap Penzoil crap looses viscosity and you end up with ZERO oil pressure instead. I've had it happen. Dodge mini van. Lost pressure on the road. Took it to the nearest shop and replaced the oil with Castrol GTX (just because it was available and not Penzoil) and the problem dissapeared - for good.

Reply to
clare

Reply to
Ken Pisichko

Reply to
Ken Pisichko

Reply to
Ken Pisichko

I notice Costco here in Winnipeg no longer sells any Penzoil products, but still sell Castrol etc. They used to sell Penzoil but stopped.

Me? I buy Texaco Ursa or Shell Rotella by the pail and use it in my wife's Volvo and in my Voyager. Both engines have filter (Hastings or Mopar) and oil changed every 5000 km. No problems with the Volvo so far and it has nearly 400,000 km on the original engine. Voyager is about

90,000 km on a long block.

clare, @, snyder.> >

Reply to
Ken Pisichko

Sorry for the repeat postings. It seems that my mailer looked at the sender's address with the comma after the @ and sent an error message, BUT still posted to the news group. Dumb me.... :-(

Reply to
Ken Pisichko

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