A few basic questions; oil pressure, aux. fan, wierd suspension movement

Hey guys, I've been MIA for awhile, but I've been driving the Jeep all this time quite successfully. The oil leak is still evading us, it might still be the rear main seal, but it's not dropping enough oil for us to be sure and we haven't gone in to examine properly (oops).

For reference: '95 Sport, 4wd, Auto, 80k

Anyway, what should normal oil pressure be - and more importantly how accurate is the gauge? Mine will start pretty high, at least 3/4 and then fluctuate later on, but never drops below the half line.

Second, why might my aux. fan kick on when starting the vehicle cold... I'm think bad temp. stat - what's the normal life expectancy, and does it say anything about the history of the Jeep?

And lastly, when coasting in (D) at low to moderate speeds, I get noticable oscillations from the ass-end. Enough for me to be able to see the change in the mirrors against a trailing vehicle. Not to mention just the general gut feeling. I know the shocks are good, and the pavement is flat... so out of round tires? They've got good tread... this one really has me stumped.

Thanks as always

Jangles said:

Anyway, what should normal oil pressure be - and more importantly how accurate is the gauge? Mine will start pretty high, at least 3/4 and then fluctuate later on, but never drops below the half line.

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Per the FSM, normal oil pressure is 13 psi minimum at 650 RPM idle, and 37 to 75 psi above 1600 RPM (engine warm). Sounds like your pressure is fine. Factory gauge is notoriously inaccurate, however.

Second, why might my aux. fan kick on when starting the vehicle cold... I'm think bad temp. stat - what's the normal life expectancy, and does it say anything about the history of the Jeep?

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I have no idea. Never heard of this before. In a 95 your aux fan is controlled by the ECM, which receives input from the temp sender in the thermostat housing. It also responds to the a/c -- any chance this is happening because you have the a/c on when you start the engine?

And lastly, when coasting in (D) at low to moderate speeds, I get noticable oscillations from the ass-end. Enough for me to be able to see the change in the mirrors against a trailing vehicle. Not to mention just the general gut feeling. I know the shocks are good, and the pavement is flat... so out of round tires? They've got good tread... this one really has me stumped.

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Bent wheel or bent axle, or maybe a tire that slipped a belt.

Thanks as always [/B][/QUOTE]

Thanks Eagle,

The aux fan isn't related to the A/C ... I've actually only run that once. Basically the only reason I noticed that the fan was running is that I happened to step out just after starting it, and I could hear it... turbine like... very noisy at 7am I've also noticed it spin up (feel the added vibration) at other "seemingly" random times. I guess I'm going to have to pay closer attention.

And the rear... a bent axle or wheel, I hope not. But, the oscillations stop if I acclerate at all. Again, I only noticed it while coasting on the highway @ 25mph because of a construction site. Gave me lots of time experiment... there aren't any bends on the exterior of the rims anyway. And ASFAIK it's never been very far off the beaten path, and has never carried heavy loads. How might one go around checking for a bent axle though?

Are you certain it's the aux fan you hear, and not the mechanical fan? The mechanical fan is mounted on a viscous "clutch" drive. This is filled with silicone fluid, and sometimes the fluid settles when parkerd for a long period (such as overnight), making quite a racket when the engine is first started.

aux fan goes on with defrost too.

That's it! If that's true, that makes sense because it didn't fire up today and I remember now that I've had the defrost setting on previous days... but not this morning. Why would it come on with the defrost though? That seems like a very strange system.

New question: what controls the low fuel light on the dash? Mine is coming on at an indicated 1/4 tank... sorta annoying. I was wondering if I could adjust that or remove it or....

The defrost setting also runs the a/c, so the air blowing onto the windshield is drier. This removes fog quicker. It also cycles the a/c during the winter to keep the seals pliable. Not wierd -- most American cars are the same way. It's the foreign iron that has a separate push button to engage the a/c compressor.

Low fuel light is set to come on with around 4 to 5 gallons in the tank, which is about 1/4. I don't believe it's adjustable. Why fight it? If you're that low, it's time to feed baby anyway. Remember that the fuel pump is in the tank and uses the gas as coolant. Let it run down too far for too long and the pump can overheat.

Ahh... that makes sense. I've only worked on my other "european iron" which has a magic button for the A/C ... although I've removed the A/C to save weight

And why run it that low? Right now I'm only going through my 2nd tank of gas and I'm trying to benchmark it and see how far it will go, and what sort of MPG I'm getting. After that I suppose I can fill up sooner. In the winter though, I won't be able to because I work weekends in an area were fuel isn't readily available... so I usually find myself running the tank fairly low... and I just hate warning lights and the like. The first thing I did to this Jeep was rip the door buzzer out. A particularly noisy one I might add.

On a side note, I seem to be getting roughly 300mi on 16-17gal fill up, the guage is sort of... umm... special. I get about 200mi out of the first indicated half, and then only that last 100 from the second half. Oh well, at least it works right?


OOH - yet another question - they grow on trees! The radio reception is non-existent so I think it might have been jogged free from the back of the head unit. It appears the dash has to be removed, is it as easy as I think it is? I can see visible screws is that about it? Or... is there any sort of magical wand I need to use that I'm not aware of.

You don't need a gas gauge to calculate fuel mileage. Fill up at your favorite station. Drive. Fill up again at same station. Divide miles driven by number of gallons used to fill tank (the second time). Result is gas mileage. You never even have to look at the gas gauge.

Tank is 20 gallons. If you're getting 300 miles on about 17 gallons, that's 17.6 MPG. At that rate, your maximum range if you run it dry is 350 miles. Now you know.

I have an older XJ and I get better mileage. Nonetheless, around town I start looking for gas when I hit 250 miles, and on a trip I start looking around 300 to 350, even though I can probably drive 450 on a tank.

RE the radio- nothing to it, remove all visible screws from dash trim panel (bezel) and carefully remove (note one pointing verticaly by cigarette lighter and another on other side of steering wheel). radio is 4 more you will be able to see and badabing you are out!