04 6.0 oil pressure fluctuations

[DenaliJJ]

hey guys. So I’m wondering if I have a pinched o ring and pump going out or if it’s just a pressure switch/screwy connection some where. Anyways after a drive around town unnoticed when I put the Yukon in park the oil level would bounce around from 35-30 Just a low drop for a second or two and the back up 35 sometimes 40 and drop again and repeat the process. Any ideas?

 

[retiredsparky]

You are correct-it is the o-ring leaking most likely.

You could replace the sensor, but I don't think that is the problem.

Unless you have a poorly maintained truck, the oil pumps last a long time. That said, if you are going to replace the o-ring, I would change out the oil pump while you are in there.
Larry

 

[OR VietVet]

If you do the sensor, do yourself a favor and hook a gauge to it and get a reading and then replace the sensor while off. would bet on the o-ring though and a new pump while in there as well. Lots of labor for just an o-ring replacement. Bite the bullet and do the pump as well.

 

[Rocket Man]

First, have you replaced the pump recently? If not, the chances it's the o-ring are minimal- that's usually the case only when it gets pinched when installing a pump and also usually shows up immediately. If it's been in place for a long time and the oil pressure was steady, it shouldn't suddenly start leaking around it since the oil pickup tube doesn't move so it can't damage the o-ring. Regardless, I'd make damn sure it isn't the sending unit OR the stepper motor in the gauge before resorting to the oil pump since the pump/ o-ring is a lot of work. And if you do the pump, might as well do the timing set.

 

[OR VietVet]

I have to disagree. While I know it can happen when changing a pump or screen, it has been a known failure with these same symtoms numerous times and is well documented on this forum. Check with mech gauge as well.

 

[Rocket Man]

I have to disagree with that. Show me some links where the o ring suddenly starts failing and they didn't just replace the pump. And explain how that happens. They don't just start disentegrating, they're rubber. I took mine out at 150,000 miles and it looked new. It happens when they get pinched during install because it's hard to get the pump aligned without dropping the pan and people don't want to drop the pan.

 

[OR VietVet]

I have been away from the forum for almost 2 years and did see posts as I spoke of. The seal is rubber and can break down over time. There is nothing I can say to convince you so I will let it go at that. If anyone thinks that any part, made of rubber or steel or plastic or whatever, cannot break down over time, well I will not say more on the subject. In the almost 35 years I ran shops I saw things that completely surprised me and did not expect but it does happen and can be a pattern failure. Not all engines get proper treatment and therefore parts break down gets accelerated in those engines.

 

[DenaliJJ]

Hey guys thanks for the replies. Sorry I’ve been away a while. Busy with kids and work. Is this an issue that needs to be addressed right away? Pressure never drops far (5psi). If it’s needed ASAP I’ll have to take a day off here before it gets too cold and just do pump and o ring. No strange noises and runs great so hell idk. Let me know

 

[OR VietVet]

IMO, I would not worry about it for now but watch it.

 

[DenaliJJ]

Here is a short video of it. This was after an hour drive. I rev the motor about half way through to about 1500 rpms