Oil pressure oddity

[Tahoehybrid18]

So...... saga continues. Took a long trip today, about 2 hrs on continuous driving. The last 15 mins, oil gauge went to about 5, stop engine now message. Still drove about another 15 mins as i was on the interstate in a not great area to stop, but what I've also learned as when this happens is the oil pressure is actually fine. As soon as i got off the interstate, and got to slow done enough that auto stop kicked in, when I accelerated enough, the engine kicked back on and oil pressure was back to normal, what gives?

 

[swathdiver]

So...... saga continues. Took a long trip today, about 2 hrs on continuous driving. The last 15 mins, oil gauge went to about 5, stop engine now message. Still drove about another 15 mins as i was on the interstate in a not great area to stop, but what I've also learned as when this happens is the oil pressure is actually fine. As soon as i got off the interstate, and got to slow done enough that auto stop kicked in, when I accelerated enough, the engine kicked back on and oil pressure was back to normal, what gives?

Ok, I just read through every post to refresh my memory. Since you were flushing gunk out of your engine, change just the filter and top off the oil. Cut the filter open and look for gunk and goo. If the problem comes back and the filter is clean, change your o-ring. Average lifespan of those things is 160K miles.

 

[Tahoehybrid18]

Ok, I just read through every post to refresh my memory. Since you were flushing gunk out of your engine, change just the filter and top off the oil. Cut the filter open and look for gunk and goo. If the problem comes back and the filter is clean, change your o-ring. Average lifespan of those things is 160K miles.

If it was the oil ring, would the oil pressure be constantly bad?

 

[swathdiver]

If it was the oil ring, would the oil pressure be constantly bad?

Not necessarily. The check for the o-ring is to overfill the motor with oil by 1 or 2 quarts and while letting it idle (don't drive it) watch the oil pressure. Another way is to get her face down on a steep ramp and check then, the objective is to submerge the o-ring in oil to it is not sucking air. If there is no change, it's not the o-ring, usually.

If you look back through this year and last there are about a dozen guys who have just had to replace their o-rings on their high mileage trucks. Two this week even.

 

[Tahoehybrid18]

What's always confused me, is why just changing the oil fixes the issue, for a few months, it doesnt use any oil, the level on the dipstick is always the same, and these issues only come up with prolonged driving, 2hrs or more continuously, no breaks

 

[swathdiver]

What's always confused me, is why just changing the oil fixes the issue, for a few months, it doesnt use any oil, the level on the dipstick is always the same, and these issues only come up with prolonged driving, 2hrs or more continuously, no breaks

Well, I think those oil filter problems are from sludge build up. If the previous owner didn't change the oil frequently and used regular or blended oil there was a sludge build up. Then you come along and start running full synthetic and change it more often. Synthetic oils have a habit of breaking down sludge and getting it moving where it winds up in the oil filter.

I'm speculating of course, the only way you'll know for sure is to cut the next filter open and look at the oil that comes out during the next change. And of course, run that test for the o-ring to eliminate it.

 

[Tahoehybrid18]

I can understand that, and I will do that. But with talking with the dealer who serviced it for me orginallly, when this happens, we dont think the actual oil pressure is dropping. This last time I drove 5 miles at highway speed with it at 3 psi, and the engine was stone quiet. He said, eith low, it no oil pressure, the valve train would be making crazy noise from lack of lubrication, but engine was quiet and ran smooth. Now, from reading on here. The passage the pressure sensor uses is the same as the one for the AFM, if so, is it possible the AFM is bleeding the pressure off some how, and not letting the sensor to get a proper reading?

 

[Wolfbraid]

After I did the Oil Pressure Sensor and the Screen, I had to do a couple oil changes with flush in a short amount of time for the problem to go away. I haven't seen it since.
I've also started using the delco filter, I had previously used a Mobile 1(mid or upper range not sure) and a K&N, seems delco is favorite around here.
I know its a pain, but if you can pull the screen it might give you an idea if that's causing it.

 

[Tahoehybrid18]

So a new update!! One day a few weeks ago, just out of the blue, oil pressure dropped from consistently 45 cold to 35 hot, to 40 cold 20 hot. So I replaced just the filter and boom, 60 cold. Bad filters? I use the delco filter.

 

[bfourman]

I switched from AC Delco filters to K&N because the "E" series filters use plastic internals vs metal. The longer HP2011 filter was the top recommendation I found on this site with the Mobil 1 second.