Oil Pressure Hits Zero And Stays There- JGC '96

c wrote:
> "NJPainter" > wrote in message
> oups.com...
>>
>> THe Valve cover and gasket is just because it needs it.
>>
>> He said he was going to clean out the "Returns". I've heard of this
>> before.
>>
>> Yes, when I restart it, after warm, the pressure goes to zero.
>>
>
> If the returns are plugged with sludge, then it could keep the oil
> from returning to the pan and cause the low pressure reading. I have
> seen the returns plug up on a few engines, but it is normally caused
> from severe neglect of oil changes, coupled with lots of short trips
> that prevent the engine from reaching operating temperature. I agree
> with the others, put a mechanical gage on it first, and see what you
> get. It is possible that the sending unit craps out when hot, or
> there is some other temperature related electrical failure happening.
> I'm sure the gage will be cheaper than the cleaning job from your
> mechanic.

I'm not a fan of oil additives like lucas (or any additives in fact).
Lucas makes the oil tend to cling to parts, which in turn robs it
from the oil sump. It can also cause it to stick to the engine walls
and bake, forming sludge. Not sure how well it works though a filter.
Generally the consensus is, if it was good for the engine the oil vendors
would already have it in the mix.

Do the mechanical gauge. Also check the oil pressure senders return wire
for kinks/burns/chafe. 0psi is <1 ohm to ground which is usually a short
or a bad sender. You can measure the sender with a digital multimeter.
Just go between the pin and the engine block. If it's measuring
0 psi = 1 Ohm
40 psi = 32.5 Ohm
80 psi = 87 Ohm

When it's warm and the pressure indicating zero, check the dipstick
and see what the level actually is. You will know then if it's being
held up in the valve cover. (actually the valve cover can not contain
that much oil without blowing it into the intake. Look down the oil
fill cap.

You can clean out the oil system using sea-foam from NAPA, and a few
oil changes. Figure which one is worth more, your time or money.

--
DougW

NJPainter wrote:
>
> CHECK GAUGES: Zero Oil Pressure reading-
>
> First had this problem on my way back home, I stuck in traffic, in the
> middle of the summer. It was a hot day, and I had been driving for 40
> minutes. I was at 4,000miles with my oil, which is 5 part synthetic,
> 1 part Lucas.
>
> I told my mechanic that I though the problem might have to so with
> dirty oil, because I'd never let the oil go for that long and I'd never
> had this problem before
>
> Mechanic changed the oil and the sensor. Nothing Happened. The light
> would come on after the car warmed up for a while. Replaced the Oil
> Pump- No Dirt in the screen. No change except for higher pressure on
> Start-Up. Used to be 40-45, now is 50-60.
>
> The problem used to happen after 20 minutes. Now it happens within5
> minutes. In addition, the pressure used to go back up with
> acceleration, but when it hits Zero, it stays there.
>
> The mechanics first suggestion was to pull the valve covers, and
> replace them, after cleaning out the RETURNS. Now he says he wants to
> have the CPU reset first, but that costs $100 and may not solve the
> problem.
>
> What's the deal?

The 'deal' is your 'mechanic' is ripping you off blind!

He is 'totally' incompetent and show this by changing bull**** parts
without testing the oil pressure with a real gauge.

You should have a good case for small claims court. Bull**** rip off
artists like that shouldn't be allowed to stay in business.

He gives a whole new meaning to the word $tealership.

It is more than obviously an electrical fault seeing as the engine keeps
on running with the supposedly zero oil pressure. When the oil pressure
'really' drops to zero, the engine will start making bad valve noises
within seconds or minutes at the most.

And 'no' cleaning the 'returns' is only his way of suckering you for
more cash. The only thing he wants to clean is your wallet!

It is also 'super' easy to clear the CPU codes... Just disconnect the
battery for a few minutes.... There are also auto store places that
will check the codes for free.

You can get a mechanical gauge and screw it in yourself or you should
find a 'real' mechanic, not the thief you have.

I was serious about bringing him to court too. The local newspapers
might like the story too.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

billy ray wrote:
> Perhaps I missed something..
>
> Did the mechanic, or the back up mechanic, ever put a mechanical pressure
> gauge on the engine or are you relying on the dash gauge?
>
>


No they didn't do the mechanical gauge.

First off,THANKS TO EVERYONE THAT HAS REPLIED!... I regret not
stopping here first, everyone's been helpful.


Problem is, I have no idea to do any of these things. My mechanic is
probably being lazy- so I guess the Jeep dealer will find the problem
tomorrow morning... it stinks...

My mechanic is down the street from me so it's really convenient. He's
usually fair with his price, and has done the exhaust manifold for me
and cat-back exhaust. At this point I'm annoyed that he didn't figure
out the problem but what am I gonna do? I don't have the tools to do
any of this.

The reason why I think it's a physical thing is because I let the oil
go too long. That's why I think cleaning the returns would work. If
that's the case the mechanic won't charge me much, he know he didn't do
his due diligence. He just put the new sensor on and thought that it
would be fixed.

Anyone have any tips on dealing with a dealership mechanic? I don't
want to get a $200 bill for diagnostics and then have them tell me it's
another amount of money to fix the problem...

NJPainter wrote:
> First off,THANKS TO EVERYONE THAT HAS REPLIED!... I regret not
> stopping here first, everyone's been helpful.
>
>
> Problem is, I have no idea to do any of these things.

Neither did any of us till we started learning.

It's not rocket science. Start simple and work your way up
or dive in and get the t-shirt. I started by simply rotating
tires, did shocks, replaced spark plugs and other fiddly bits.
Eventually I tried my hand at rebuilding a carurator, twice.
Now I'm up to the point where installing a stroker kit sounds
like fun. (sick isn't it.) But each time I do something the
money saved pays for more tools.

> Anyone have any tips on dealing with a dealership mechanic? I don't
> want to get a $200 bill for diagnostics and then have them tell me
> it's another amount of money to fix the problem...

The dealership mechanic will have a set charge for diagnostics and
usually apply that against any labor/part charge for fixing the problem.
Thing is dealerships aren't cheap places to get labor done. But
sometimes they are the only place to turn.

--
-- DougW -- 93 ZJ 4.0 http://revbeergoggles.com
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors
Banks Header - and BEER, in the fridge!

thanks for the advice and the inspiration...

I'm a little scared about going to the dealership. I won't be able to
negotiate price, so I hope I get a cool mechanic to work with. I hope
it's something small, but I'll probably back on here tomorrow crying
about how much I just spent.

How do you do your own work without a lift?

NJPainter wrote:
> thanks for the advice and the inspiration...
>
> I'm a little scared about going to the dealership. I won't be able to
> negotiate price, so I hope I get a cool mechanic to work with. I hope
> it's something small, but I'll probably back on here tomorrow crying
> about how much I just spent.
>
> How do you do your own work without a lift?

Not everything requires a lift. I use a 3ton floor jack
and heavy duty jack stands when there isn't enough room to
slide under the jeep. The biggest problem I run into is
stuck bolts, but even then there are ways around that.
http://www.revbeergoggles.com/temp/oomph.jpg

That was one way to loosen a stuck axle bolt.
Not graceful, but it works. I need to buy
an air wrench.


--
DougW

You can rent, often for free, a mechanical oil pressure gauge from many
auto-parts stores. It is simple to attach, you remove the oil pressure
sender with a wrench and screw in the mechanical gauge and you read the
actual pressure directly.

From your post I think that this oil change was delayed to 4000 miles. This
is more than the 3k interval that will give you maximum engine life but less
than the warranty requirement.

Upon getting an zero pressure reading off a dashboard gauge you mechanic's
first step should have been checking the actual pressure with a mechanical
gauge.

This is not a 'Jeep thing' this would hold true of any engine that uses
electrical senders (most if not all).

We all started somewhere, if the mechanical gauge shows proper pressure then
the sender or wiring is at fault. This would not be the first or last
sender that was defective new from the box.

If, in fact, your pressure falls off then you have valuable information to
give your new mechanic.

Most vehicle maintenance can be done without a lift. Sometimes you need a
set of ramps or jack stands but they can be obtained at any auto parts store
as well as K-Mart, Wall-Mart, Sears, etc.

A basic tool set is not expensive and any tool you buy will be paid for the
first time you use it. Do not buy poor quality or made in Red China tools.
Specialty tools, such as this mechanical oil pressure gauge, can be rented
at many auto-parts stores... just ask. The worse thing they could do for
asking is castrate or kill you.... they won't harm your Jeep or anything
serious.

A good reference manual is always helpful when you start... The best manual
is the Factory Service Manual specific to your make and model. They can
often be obtained second hand on eBay in both paper and CD format.
http://tinyurl.com/y8jujj



"NJPainter" > wrote in message
ups.com...
>
> thanks for the advice and the inspiration...
>
> I'm a little scared about going to the dealership. I won't be able to
> negotiate price, so I hope I get a cool mechanic to work with. I hope
> it's something small, but I'll probably back on here tomorrow crying
> about how much I just spent.
>
> How do you do your own work without a lift?
>

4000 miles isn't really that long, and it's not NEARLY enough to cause
the kind of problem you are having. If you regularly drove it 10,000
miles or more between oil changes then you could have this problem, but
not one 4,000 interval.

Jeff DeWitt

NJPainter wrote:
> First off,THANKS TO EVERYONE THAT HAS REPLIED!... I regret not
> stopping here first, everyone's been helpful.
>
>
> Problem is, I have no idea to do any of these things. My mechanic is
> probably being lazy- so I guess the Jeep dealer will find the problem
> tomorrow morning... it stinks...
>
> My mechanic is down the street from me so it's really convenient. He's
> usually fair with his price, and has done the exhaust manifold for me
> and cat-back exhaust. At this point I'm annoyed that he didn't figure
> out the problem but what am I gonna do? I don't have the tools to do
> any of this.
>
> The reason why I think it's a physical thing is because I let the oil
> go too long. That's why I think cleaning the returns would work. If
> that's the case the mechanic won't charge me much, he know he didn't do
> his due diligence. He just put the new sensor on and thought that it
> would be fixed.
>
> Anyone have any tips on dealing with a dealership mechanic? I don't
> want to get a $200 bill for diagnostics and then have them tell me it's
> another amount of money to fix the problem...
>

In article >,
Mike Romain > wrote:
#It is more than obviously an electrical fault seeing as the engine keeps
#on running with the supposedly zero oil pressure. When the oil pressure
#'really' drops to zero, the engine will start making bad valve noises
#within seconds or minutes at the most.
I agree with Mike on this. When my '99 WJ had a like issue, I took it
back to the dealership multiple times under warrenty, but as luck would
have it, it always "fixed" itself when in the shop. The dealer finaly
was able to catch it zero'ed out and traced the fault to a bad electrical
line. Had to run a bypass wire.

#It is also 'super' easy to clear the CPU codes... Just disconnect the
#battery for a few minutes.... There are also auto store places that
#will check the codes for free.
Checking them should just be a matter of turn the ignition on, off, on,
off, on without cranking...

/herb