Any significant damage from no oil pressure

[OUCaptain]

Took my new (to me) Jeep out this weekend for a test run to make sure all is well before the factory warranty expires. On a few of the climbs, the oil pressure fell to zero for a few seconds, 5 at the most, until I got her over the top and level again. The engine barely got above idle speed each time since I was playing with the low range and lockers. I doubt there was enough time for any significant damage to have occurred but thought some more opinions.

Side note, the Rubicon kicks ass off road. Way more capable than my first jeep. The lockers make this thing almost unstoppable.

 

[bruceb]

Probably no damage, but that is why racers run what is known as a "dry sump" oil system .. It can provide pressure no matter what the direction of the oil pan as it relies on an external pump to scavenge the oil from the pan, whereas the internal pump
can cavitate under certain conditons.

 

[chucky2]

When lugging the engine, you definitely want oil flow...so I'm sure some additional wear occurred than would have normally.

If your ride is still running the same, then there's really not much you'll be able to do about it.

Might want to change the oil and filter just in case you've got any cr@p floating around in the oil...

Chuck

 

[iamwiz82]

I assume this is the 4.0 and not the 2.4? It probably never lost oil pressure, you probably have a faulty oil pressure sending unit. It's in a bad location and gets battered when you change the oil filter, so they don't last long.

 

[GalvanizedYankee]

Damage...probably not. Rod bearings seem to be the first thing to go from oil starvation btw.

iamwiz82 may be right about the sending unit. It is very easy to replace and inexpensive.

Dry sump?=expensive. Consider something like this http://www.thinkauto.com/accumulators.htm

ASIDE: I had a Moto Guzzi with a oil pressure relief valve that would stick open quite often for seconds at a time.
Never caused an issue with a rod bearing, although i did change the rod bearings along with the relief valve.

 

[OUCaptain]

4.0 only in the rubicon. 2.4 would just be stupid considering everything else they upgraded. Considering the very steep angle I was at and the location of the pick up, I'm almost positive the pump was sucking air. If the approach had been any sharper, my rear bumper would have scraped. The gauge hit zero right when I hit the steepest part and recovered immediately after I crested the top.

I forgot all about an accumulator. If I start taking her out on the trail more often, that will definitely go on the upgrade list.

 

[Bignate603]

You're probably ok, the 4.0 has ridiculously low oil pressure at low RPM. Factory spec at idle is a whopping 7 psi at idle.

 

[Pacfanweb]

It didn't hurt anything. As mentioned before, the 4.0 doesn't have that much pressure, and honestly...at idle, you don't need much. The gauge isn't that accurate....general rule of thumb for most engines is 10psi per 1000rpm...if you were idling, you didn't even need the 10psi, so you were fine.

And yeah, the Rubicon is the most capable factory-build 4x4 ever produced...nothing stock can go where they go.

 

[Bignate603]

I was just thinking about something, the oil pickup is ridiculously low and far back. It's set up to make it pretty darn hard to starve the pickup without going completely vertical or being low on oil before hand. I'm talking like 'need a winch to drag yourself up a rock face' vertical. It's much more likely that your oil sensor was acting up. My cherokee's had to be replaced, it's common and its really cheap and easy. It's right on the side of the engine.

 

[OUCaptain]

Originally posted by: Bignate603
I was just thinking about something, the oil pickup is ridiculously low and far back. It's set up to make it pretty darn hard to starve the pickup without going completely vertical or being low on oil before hand. I'm talking like 'need a winch to drag yourself up a rock face' vertical. It's much more likely that your oil sensor was acting up. My cherokee's had to be replaced, it's common and its really cheap and easy. It's right on the side of the engine.

Wiz pointed that out but I havn't had the chance to check it. As you said, the pickup is at the far back bottom of the pan (at least it was on my 99 4.0). Makes me wonder or fear the peck up has moved, broken, cracked, or jacked up in some fashion.