jeep 4L oil pressure

171,000 mi. on 96 4L. Oil pressure drop too 0 after 4 or 5 mi. of running
at 60mph then stopping. I just replaced the oil pump and still have the
same problem, only worse now. It is an aftermarket pump, could I have just
installed a bad pump?

Oil pressure depends on pump quality and bearing clearance both. If you put
a new pump on an engine with bad bearings, then you didn't help yourself
much. Did you check the accuracy of the oil gauge before installing the new
pump? Isolated oil pump failures are rare, because the pump is the best
lubricated part of the engine. They do happen, of course, but they are
rare.

Earle

"ansky" > wrote in message
lkaboutautos.com...
> 171,000 mi. on 96 4L. Oil pressure drop too 0 after 4 or 5 mi. of running
> at 60mph then stopping. I just replaced the oil pump and still have the
> same problem, only worse now. It is an aftermarket pump, could I have just
> installed a bad pump?
>

Thank you Earle. I was thinking that was the problem but, I was in denial
and hopping for another answer.

Verify the oil pressure with a Real gauge, like all Hot Rodders use
aftermarket sets by Stewart Warner: http://www.stewartwarner.com/ or
Auto Meter: http://www.autometer.com/
God Bless America, ßill O|||||||O
http://www.billhughes.com/

ansky wrote:
>
> 171,000 mi. on 96 4L. Oil pressure drop too 0 after 4 or 5 mi. of running
> at 60mph then stopping. I just replaced the oil pump and still have the
> same problem, only worse now. It is an aftermarket pump, could I have just
> installed a bad pump?

I'm with Earle on this one, but with a caveat.

The oil pressure sending unit could be a problem area that you should look
at before you go in search of the bad bearings. The sending unit uses a
variable resistor of some sort mounted to a diaphram. The diaphram can get a
hole in it, and give strange oil pressure readings. It is common for the oil
pressure to drop at idle, then come back as the engine speeds pick up, but I
don't think that a drop all of the way to zero is right.




"ansky" > wrote in message
lkaboutautos.com...
> 171,000 mi. on 96 4L. Oil pressure drop too 0 after 4 or 5 mi. of running
> at 60mph then stopping. I just replaced the oil pump and still have the
> same problem, only worse now. It is an aftermarket pump, could I have just
> installed a bad pump?
>

Well, if it really goes to 0 at idle, you will 'hear' about it. The
valves will start clacking really fast.

Usually that trouble is the sending unit above the oil filter. They are
poor quality and fail lots. The fact it got worse also implies the
sender is fast going dead.

Second is a main bearing, but again if you have mains that bad, you
should be able to hear a knock or rumble vibration at idle.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

ansky wrote:
>
> 171,000 mi. on 96 4L. Oil pressure drop too 0 after 4 or 5 mi. of running
> at 60mph then stopping. I just replaced the oil pump and still have the
> same problem, only worse now. It is an aftermarket pump, could I have just
> installed a bad pump?

My '95 ZJ does the same thing and has for a couple years...I've jus been to
cheap and lazy to change the sensor...one of these days!
kinda freaks u out for the first while watching the gauge drop off to
zero...
Jeff
'03 TJ & '95 ZJ



"Mike Romain" > wrote in message
...
> Well, if it really goes to 0 at idle, you will 'hear' about it. The
> valves will start clacking really fast.
>
> Usually that trouble is the sending unit above the oil filter. They are
> poor quality and fail lots. The fact it got worse also implies the
> sender is fast going dead.
>
> Second is a main bearing, but again if you have mains that bad, you
> should be able to hear a knock or rumble vibration at idle.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> ansky wrote:
>>
>> 171,000 mi. on 96 4L. Oil pressure drop too 0 after 4 or 5 mi. of running
>> at 60mph then stopping. I just replaced the oil pump and still have the
>> same problem, only worse now. It is an aftermarket pump, could I have
>> just
>> installed a bad pump?

Is there a 't' fitting for mechanical oil gauges? ( To be able to leave the
original sender attached, and attach the line for a mechanical gauge?) I
would have attached a mechanical pressure gauge long ago on my son's
wrangler, but haven't done so because of the computer turning on the 'check
gauges' light and sounding a tone when the pressure sender is disconnected.

thanks!

cal


"ansky" > wrote in message
lkaboutautos.com...
> 171,000 mi. on 96 4L. Oil pressure drop too 0 after 4 or 5 mi. of running
> at 60mph then stopping. I just replaced the oil pump and still have the
> same problem, only worse now. It is an aftermarket pump, could I have just
> installed a bad pump?
>

Cal did pass the time by typing:
> Is there a 't' fitting for mechanical oil gauges? ( To be able to leave the
> original sender attached, and attach the line for a mechanical gauge?) I
> would have attached a mechanical pressure gauge long ago on my son's
> wrangler, but haven't done so because of the computer turning on the 'check
> gauges' light and sounding a tone when the pressure sender is disconnected.

Any brass T fitting that has the right threads will work.

--
DougW

Where there's a will there's a "T" fitting.
http://www.stewartwarner.com/ http://www.autometer.com/
God Bless America, ßill O|||||||O
http://www.billhughes.com/

Cal wrote:
>
> Is there a 't' fitting for mechanical oil gauges? ( To be able to leave the
> original sender attached, and attach the line for a mechanical gauge?) I
> would have attached a mechanical pressure gauge long ago on my son's
> wrangler, but haven't done so because of the computer turning on the 'check
> gauges' light and sounding a tone when the pressure sender is disconnected.
>
> thanks!
>
> cal