ZondaLegs

Hello all, I have an 05 suburban with the L59 5.3. A couple months ago my oil pressure dropped to zero as I was driving to work one morning. I had it towed home and when I fired it up at home it had a nasty sounding tick. I read on another forum that there is an O ring in the oil pan that can crack and not allow oil up into the valve train. So I overfilled it and jacked the rear end up to test but I had no luck. I would rather not replace the motor simply due to cost, I am wondering what kind of issue could’ve caused this since it’s not smoking out the exhaust pipe and it’s not leaking under the truck. Any ideas would be appreciated.

thanks!
Connor

strutaeng

It's the oil pan pickup tube O-ring where it bolts to the oil from at the front of the engine. It's definitely an item that can cause issues with age and mileage. You can access it by removing the oil pan. It's not too difficult on 2wd models.

Have you drained the oil? If bearings are worn, you will see a glittery appearance on the oil. Use a very clean pan to collect it and shine a flashlight into it. It will be very obvious.

If oil looks good, you can purchase an oil pressure mechanical guage to see how much pressure you actually have. The gauge on the clusters usually report lower pressure than what you have, in my experience.

wretched73

iTrader: (1)

And cut open the oil filter and inspect it

How many miles and any mods?

ZondaLegs

157990, I haven’t done anything except a cold air intake as it was my daily and didn’t want to put a ton of money into a worn motor like this one

ZondaLegs

I live in Utah, but back in January it was real cold so when I jacked the rear end up to test for the O ring issue I got no dice, however just yesterday I went over there and dumped sea foam and ATF into it and got slight pressure. That leads me to believe it’s a clogged pickup tube with a pinhole in it, or a cracked O ring that was only getting slight pressure because it’s way overfull. My guess was that I had no dice in January because it was cold and the oil was too thick because the motor couldn’t warm it up.

MikeGyver

iTrader: (5)

As far as plugging the inlet screen, have you ever overheated the engine? It doesn't take long to make tar that will fall off the crankcase walls or elsewhere later and plug the inlet.

joom

Have you changed the oil and filter since you started experiencing this lack of oil pressure ? It's one of the least expensive things to try .

ZondaLegs

I have, didn’t see anything out of the ordinary. Tested with a magnet too. I also cut the filter open and didn’t see any particulates.

ZondaLegs

as far as I know, the motor hasn’t been overheated though I’m not sure what I would be looking for to figure that out. I’ve owned it since roughly 135k miles

wretched73

iTrader: (1)

as @strutaeng mentioned, put a mechanical gauge on it and confirm its not a bad sensor.