96 Dakota 4x4, auto trans., about 165k mileage. INTERMITTENTLY when driving oil pressure will drop and warning light comes on. I pull over, turn off the engine, count to 10 and I am good for anywhere from 1 mile to over 120 miles. First time it happened I was on 500 mile round trip and roughly 20 miles into the drive this happened. It happened 15 to 20 times in 225 miles. I returned home the next day with no problems. On the last trip...same destination it only happened 2 times.. My logic says if it was worn bearings it would not be so intermittent. The oil level is always good. I am thinking a damaged,,,cracked maybe...or worn oil pump. A side note, I live in Mexico and sometimes on these long drives I go through high desert and it is very hot. With that in mind and the mileage I switched to 20w50 oil about six months before this first happened. Any feedback is greatly appreciated.

 

Probably just a sending unit on its way out. You can just replace it, and see what happens, or, you can put a mechanical gauge on it, and see what pressure is REALLY doing.... (and then replace the sensor. )

 

Talked with the mechanic I use for major problems yesterday and he agrees that it probably is not caused by bearing wear and he suggested exactly what you are suggesting. He also suggested to flat out install a mechanical gauge, which makes sense because the problem is so intermittent. Ordered one yesterday and having it installed tomorrow. Because the problem is so intermittent, it may take a while to show it is caused by something other than the original electric gauge. Thanks for the reply.

 

This is just my opinion, but I would skip the guage and replace the sender for the following reasons.
1. They are about $20.00 a test guage will be that or more. and then you still will have to buy the sending unit if bad.
2. When bearings wear, pressure may be ok when cold but not when hot, because the oil is thin. But it is very repeatable. Not just intermittent.
3 Oil pressure switch and temp. switch seem to fail alot on these trucks.Its a common problem.
Just my opinion!!

 

@93 ragtop I appreciate what you are saying but the first time it happened I had a new oil press. sensor installed and the pressure dropped within 20 miles of the installation of the new sensor. What I may do is find a t fitting and have both the original gauge and sensor plus the mechanical gauge. Thanks for the reply.

 

That sounds like a good plan. That will tell you if it's an electrical problem, or something else.

 

Plus I have made two trips on the same route that it first happened and one time no issue at all and the last time on long 2 plus mile drive uphill on a very hot day the light flickered on and off. The gauge showed very low pressure but still had some pressure and as soon as the light flickered back on there was pressure showing on the gauge. The rest of that trip there was no problem.

 

could be something in the pan (sludge?) that is able to "lose its grip" when the suction of the oil pump is released, (pump not sucking oil) while engine is shut off... if it is able to temporarily "float away" from the pickup with the oil draining back from the top end of the engine, and randomly getting stuck again in the pickup. I do not like how the drain plug is located on these because there is about 3/4" of oil that never gets drained out unless you pull the pan. the dirtiest of the oil stays in the pan below that point. That is a lot of why frequent oil changes and running the engine just before draining the oil is so important.
I agree with the "T", keeping the original sending unit and adding a manual gauge in addition. simple to find, that is typical 1/8" NPT thread ("national pipe taper") My 96 does the same thing (no light though) my dash gauge is goofy, when cool/cold out the gauge don't "wake up" til inside of truck starts warming up, or I thunk on the gauge cluster. but no bearing noise or lifter clatter. ever. I have tested with a manual gauge in place of the sending unit "temporarily" a couple times over the lifetime of this truck being "with me" (215k total miles and climbing daily, at least 70 miles a day) Mine is a 318/ what engine is in yours?

 

On my drive home, when this happened the first time, I thought a lot about what can cause this and your idea was at the top of the list. I added a cleaning additive, let the engine idle for 15 to 20 minutes and changed the oil. About a week later made a 240 mile round trip and no problem but a month later made the same trip and the problem was back but not as frequent. So maybe yes, maybe no. The day I ordered the mechanical gauge I changed to oil but switched back to 10w30 from the 20w50 I had switched to. The next morning, early, took the truck to have the mechanical gauge installed. Upon start up, I had oil pressure a lot quicker with the lighter grade oil. I could not find a t fitting that would work so opted to just go with the mechanical gauge. I wanted to have the warning light there to grab attention but I monitor all gauges when driving so hopefully no issues not having the light. On a cool or cold start up the gauge registers 50 lbs. of pressure driving or at idle. As the engine warmed up a little the pressure went to 30 psi at idle. The other day my wife ran some errands and when she got home I immediately took off to run a couple of my errands. The engine was up to full operating temp. and at 60 mph, about 2100 rpm the pressure held at a steady 30 to 33 psi and at idle was at roughly15 psi. To me 30 psi driving and 15 psi at idle is pretty acceptable given the mileage. Leaving the 22nd on the same 240 mile round trip so I have my fingers crossed. This Dakota has the same 318 engine you have. I have always felt that the Chrysler engines were very strong and I still think that. Thanks for your interest and reply.