ZERO Oil Pressure, did I hurt anything?

This afternoon I went to go to the store which is only 2 miles away and I left the XJ running outside since it's a small town and an old car so when I come back out I see the oil pressure guage on ZERO so I went down the road and checked the oil level and it was between half and three quarters of the way below the ADD: spot on the stick, I ended up driving home like that reving the motor to keep the oil pressure up which didn't go over 20 at all(most of the time on ZERO), it was only about 5 miles and 30 minutes running total so I'm wondering if I could have fatally hurt anything. I lent it out to a relative of mine yesterday and he might have had it running for about an hour or so and I have no way of knowing what the pressure was when he was driving it.

This is a 1990 XJ Pioneer with a 4.0, 5spd and 182k.

BTW-Isn't there some kind of low oil pressure or check guages light that's supposed to light up when something like this happens?

It still seems to run fine enough

Remove the electric sender and either replace it or put on a mechanical gauge. Senders do go bad. Other thing might be to do an oil change and put a good filter on it, not fram. If you had a fram on there the cardboard might have rotted in the filter...

If it was not rapping...it is prbly the sender. Replace and advise.

Rev

I guess I'll be heading over to Auto-Scone tomorrow, how much should the sender set me back? What's the best filter to use and should I be running synthetic oil with 182k miles?

About $15 to $275.

Rev

Whoa, maybe I'll go with a mech. guage for a while...

i had this happen periodically, i always told myself it was the sender or maybe since i swapped in full cluster gauges something wasnt right. well after getting rid of fram which i used for years i have since switched to purolator(and mobil1 syn oil) and i have not had any problems since, in fact i seem to have much better pressure than before

Zoro said:

I guess I'll be heading over to Auto-Scone tomorrow, how much should the sender set me back? What's the best filter to use and should I be running synthetic oil with 182k miles?

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I'd like advice about synthetic oil as well. I was told by a knowledgable elder that synthetic oil was not reccomended for older engines, and could actually cause leaks because the seals were "conditioned" to regular oil. I'd love to reap the benefits of synthetic oil, but since my XJ doesn't leak any so far, I'd rather not have it start.

BruteXJ said:

I'd like advice about synthetic oil as well. I was told by a knowledgable elder that synthetic oil was not reccomended for older engines, and could actually cause leaks because the seals were "conditioned" to regular oil. I'd love to reap the benefits of synthetic oil, but since my XJ doesn't leak any so far, I'd rather not have it start.

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They are not conditioned they are dried out and cracked. The old regular oil rests in those cracks and hardens and dries out sealing them. Put Syn in and the high detergent in it will clean that stuff out. Whether the gaskets dry out on their own over time or whether the oil sludge blocking it allows them to dry out is the question, chicken or egg thing. Take a look at your valve train an see how badly that is sludged up. At worst you will be replacing the valve cover gasket, Oil filter O rings and maybe front and rear seals. My 98XJ has over 260,000mi on it and has been happy running Mobil-1.

RockAuto has senders from Standard Ignition for around $23, I think (put one on my Y2K Dakota recently, looks identical to OEM, and same as my 94 Jeep). These are common across most Mopar products. You can probably get one at a local AP store for around $30.

As to converting to Syn oil, there's a lot written on this, just do a search. The biggest issue with older engines and Syn oil is that it has slightly better solvency than dino oils, and thus tends to wash away accumulated goo from around seals and gaskets, causing leaks.

Oil Filter - WIX #51626 (metric thread used to 1990 - M20x1.5)
Oil Pressure Sensor (with gage) - oddly enough, it isn't in my BWD catalogue. If you can't find one locally, give Morris 4x4 Center (www.morris4x4center) or Leon Rosser Jeep (www.thinkjeep.com) a buzz - if it's not in the aftermarket, they're probably the best prices on OEM parts I've been able to find to date - especially Morris! They've gotten a bunch of my business lately...

Make sure you specify that you have the gage when you order the sensor.

Unless you heard some unholy racket under the hood, you're probably alright. I know that the RENIX 242 will behave when up to two full quarts low (don't ask how I know...) so you should be fine.

5-90

Just put in 3 quarts of 30 weight and it sounds ALOT better, oil pressure now registers and it isn't jumpy like it used to be...only thing is I guess I put too much oil in cause it's just over the last L on FULL on the dipstick, I'm guessing it's better to have a little more than not enough, right?

With my next oil change I'm going to run a WIX filter(running one now) as well as switch over to synthetic, probably the Mobil1 High Mileage stuff. If I gradually do the transition over to synthetic will it still leak the same as if I just start using it suddenly?

Steve C and Rich P....you answered why a switch to synthetic might result in leaks, but considering the risk of leaks, would it be worth switching? ('99 Sport 90k, no leaks, no problems...I want to keep it that way).

BruteXJ said:

Steve C and Rich P....you answered why a switch to synthetic might result in leaks, but considering the risk of leaks, would it be worth switching? ('99 Sport 90k, no leaks, no problems...I want to keep it that way).

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IMHO, if:

(1) you're concerned with longevity
(2) the added cost is acceptable to you
(3) you're prepared to fix anything that shows up after the changeover

then I think it's a good idea. I run it in both my Dakota (75Kmi) and my wife's Sebring (new), and the thing I've found that I really like about it is it's viscosity stability with temperature. It feels the same whether hot or cold, any weather. Starts (where the big wear occurs) are far quieter and easier than before, and gas mileage is a tad better too. Since we do a lot of short trips, I think it's worth the money.

That said, I had a minor issue converting my truck several months ago after I bought it at 67K miles. It's engine (Chrysler 4.7L V8) seems to have a minor rep for sludge in the pan, and in the heads. I saw some oil pressure fluctuations that bothered me, and after the first batch of Mobil 1, they got worse. Best I could tell was that the sender had some goo washed into it that blocked it, inside the pan and pickup tube turned out fairly clean. Curiously, this first batch of oil got very dirty within 300 miles, and I dumped it at 1500 miles to look inside the pan. Both batches since have stayed very clean through 3K miles.

If you want a pictorial testament to the difference between them, on an engine that's very sensitive to oil quality, go see http://t.vago.home.att.net/gallery/gallery-jr-sludgequiz.html

Don't know if I'll convert our XJ or not yet. I'm thinking I will; with 155K miles, it still runs very well, and I've no reason to think it's not going to run well for quite some time yet. It needs a rear seal and oil filter rings anyway, so those leaks are irrelevant.

5-90 said:

Oil Filter - WIX #51626 (metric thread used to 1990 - M20x1.5)
Oil Pressure Sensor (with gage) - oddly enough, it isn't in my BWD catalogue. If you can't find one locally, give Morris 4x4 Center (www.morris4x4center) or Leon Rosser Jeep (www.thinkjeep.com) a buzz - if it's not in the aftermarket, they're probably the best prices on OEM parts I've been able to find to date - especially Morris! They've gotten a bunch of my business lately...

Make sure you specify that you have the gage when you order the sensor.

Unless you heard some unholy racket under the hood, you're probably alright. I know that the RENIX 242 will behave when up to two full quarts low (don't ask how I know...) so you should be fine.

5-90

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I literally almost ran out of oil, and was a hell of a close call. We didn't know we were leaking oil even until the compression just wasnt' there. Could have been pretty bad, but we were lucky. Since then I've had to keep an eye on it, and all has been well without problems. Just had the valve cover resealed and it's made a huge difference. Still was leaking some oil though through the top of the valve cover. I replaced the grommet and ccv hose with a new one, and sems like there's no leaking there now. Going to hit Parts Source today and replace the oil filler capwith a new one as it seeps a bit there. The breather tube I've not done, although I want to do that one as well, as it's just not a nice tight fit as I want, but we'll see. Not sure how much $$$ it'll cost me as it's the entire part that has to be bought, not just the actually end rubber piece.
Same as the grommet/ccv. Only comes as a set, but the other one I've kept as a spare just in case, as the hose is virutally new. Just the grommet is seeping for some reason. A simple fix for only $12 at my local dealership.

The oil guage I've never been able to figure out exactly now it works or reads. Mine basically goes to 5 and has 4 sections to the guage. MIne usually reads between the lines of the 2nd section, but occasionally drops below that a bit. Other than that, I don't know what it's actually telling mne, or if it's off at all.

a new sender will probably help but be careful with synthetic oil,if your engine has been running normal oil since new synthetic may cause leaks.i would run 15w40 diesel oil for a couple of oil changes to clean out the engine.diesel oil is high in detergent and does a really good job cleaning up sludged up parts.

coolpete1 said:

a new sender will probably help but be careful with synthetic oil,if your engine has been running normal oil since new synthetic may cause leaks.i would run 15w40 diesel oil for a couple of oil changes to clean out the engine.diesel oil is high in detergent and does a really good job cleaning up sludged up parts.

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I've been really thinking of changing over because mine could really use the benefits of it, but I'm afraid of what if i have to redo all the seals. [rear main etc] The valve cover isn't an issue as it's been just done. Just can't afford to get anything else fixed if it should go right now, and I have to do an oil change this month.
Is it a case of it'll leak a bit? or leak like a seive? Have seen a mixture for high mileage engines that is part syn, part dino. is this worth doing? or are they're any drawbacks? Was considering maybe using it to minimize and problem with leaking. There's also lucas oil in it as well. Not sure how that would work with the syn at all.