What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[j91z28d1]

Took the tahoe out to my little patch of worthless desert and had a decent time.

Going from the jeep wrangler to the tahoe really shows how much more power and how much more comfortable it is.

On the way up there i noted something that keeps showing its ugly head.

Oil pressure fluctuating after several hours of highway driving.

I always assumed it was my stupid lifters sucking the oil pan dry and me getting some air in there.

Adding a little extra oil seemed to reduce it but then i notice a lower overall oil pressure after hours of driving, and less pressure rise.

Then while hauling the boat home, i discussed the issue with the father in law since it started happening.

Later youtube suddenly suggested a video explaining that over filling the pan in an ls can result in lower oil pressure due to foaming.


So i figured I'll bite, time to change the oil and switch to synthetic anyways.

So changed the oil,
And i didn't hit the top full line on the fill this time around.
Instead i targeted right in the middle of the full area.

Result was much better oil pressure and better oil pressure rise!!

Doing driving around the issue disappeared completely.

Until yesterday.
Right at the end of a two hour drive at anout 2k rpm the oil pressure started fluctuating.

Sitting a little over 40 on the gauge, it would dip down under it a bit, then go back over 40, sit there for a bit and then do it again.

Downshift to get the rpm back up and the pressure rise was good and solid, but back down and it returned?!?

I think its time for me to install a mechanical oil pressure gauge on one of the ports on the side of the block so i can see if it's doing it on both gauges...

I also got the bright idea to stop for a bit, let the oil settle with the engine off, but not long enough to allow the engine to cool off to see if that helped.

The answer was nope.

I also noticed it seems to happen when my voltage is up past the 14v mark...

So I'm not ruling out a possible alternator issue that shows up after several hours of driving...

I love the tahoe, but i also want it to catch fire sometimes... lol

On a happy note, it's fkn quick in those canyons.
I'm still loving the 6.0

I'm super behind but mine started fluctuating only on long hour plus road trips.. it was to fast to actually be a reading. oil is thick, I can't really flicker like a light bulb. it was the new "oem" sensor I had just put in from Amazon few 1000 miles earlier. replaced it with a dealer sensor and all fixed for a good 15k at this point. I'm convinced the Amazon oem is a counterfeit.

 

[justchecking]

Yesterday after I found my hood strut where it is supposed to be I went through the engine bay and cleaned all the battery and engine grounds and reinstalled them. Also the cable from the positive post of the alternator to the positive post of the battery. I did not want to mess with that ground connection on the back of the engine so I cleaned the body post and checked the ohms from the engine to that cable and it was good. Did add a heavier cable from that post to the mount by the alternator, though, just in case. I feel like I should add another ground point to the body for that new cable but that will have to wait for another day. I also removed the bumper and cleaned those front chassis grounds but forgot to take a pic. I had gotten a low battery warning last week but I knew my battery was good, so I hope this fixes it, as well, those other miscellaneous electrical grounds under the hood that should forstall any problems.

 

[Doubeleive]

well fuckaduck guess the sound........

 

[07Burb]

Muffler bearings need more grease

 

[Just Fishing]

I'm super behind but mine started fluctuating only on long hour plus road trips.. it was to fast to actually be a reading. oil is thick, I can't really flicker like a light bulb. it was the new "oem" sensor I had just put in from Amazon few 1000 miles earlier. replaced it with a dealer sensor and all fixed for a good 15k at this point. I'm convinced the Amazon oem is a counterfeit.

Worth a shot.
I also need to get a factory cylinder head temp sensor; I'm suspecting some issues with it when the engine is cold.

 

[iamdub]

well fuckaduck guess the sound........

Chunks of catalyst rattling in the case?

 

[Geotrash]

well fuckaduck guess the sound........

Cat rattle? Or rod bearing...

 

[Doubeleive]

Chunks of catalyst rattling in the case?

bingo! funny thing the drivers side did the exact same thing 6 months ago, finally get the cat code to go away and the passenger side cat breaks apart

 

[Doubeleive]

Cat rattle? Or rod bearing...

thankfully not the later....

 

[Geotrash]

Actually paid someone else to do an oil change on the 2012 because we're taking a camping trip starting this weekend and will be driving 1000 miles or so. It's a local quick lube that has competent techs who do good work. $95 out the door for 5w-40 Euro spec oil (engine mods).