GREENSIERRA

I have about 8000km on my LQ4 that I got all new bearings put in and freshend up, I run a melling hi volume pump that I had in my 5.3 and also put a new oring in with the LQ4.
the motor has good oil pressure all the time but when I am at a steady speed on the highway I notice the pressure fluctuating. I have drove my brothers 05 sierra, my wifes 05 Tahoe and they both fluctuate but you really have to look to notice it but on mine I can clearly see it moving, pressure is still really good but I have the truck apart with the motor out and was wondering if this is something I should worry about and get looked at while the motor is out or if anyone elses truck does this.
I haven't drove the truck in months so I don't know exactly how much it moves on the gauge.
any input would be great.

thanks, Mitch

GREENSIERRA

after looking at the wifes Tahoe I want to say it will move from one small line to the next small line on my truck, not sure how much psi that is cause its in kpa cause I am from canada

01silvy

It could be anything honestly, my truck did it when the pick up tube was getting partially clogged sith sludge. It could be a faulty oil filter, worn oil pump, cut o-ring, or a malfunctioning oil pressure sender. Since the engine is out of the truck it makes since to check main and rod clearences.

GREENSIERRA

yeah I will probably just tear it down and check while its out.
I have the body off the frame to blast and paint the frame and would hate to have to get it all dirty pulling it out after. its a lot easier to do now.
I cleaned the pick up tube and properly put a new o ring when I built the motor last time, the pump was fine in the old 5.3 and I tried a couple different brand filters and oil weights with same result.
I also had to replace the oil pressure sender and it did it with both.
I will pull the pan first and check the pickup tube and oring to make sure everything is ok.
thanks for the input and anymore from others would be great.

mitch

01silvy

No problem bud, make sure all your ground straps are attatched properly. They can affect little things too

GREENSIERRA

I always look at the stupid obvious stuff first cause I have been burned by that stuff before. lol
hope to pull the pan either tomorrow or next weekend.
had to make some extra truck money today by changing a power steering pump for a buddy.

Mitch

01silvy

Keep us updated

phnxfrhwk

Just curious if you found a "smoking gun" yet? I just noticed this on my truck about a week ago. It will flux about 5psi indicated (approx. One hash mark) on the gauge at steady rpm but never at idle. I still have good oil pressure (about 35 psi at idle). Hoping this is nothing to be overly concerned about.

GREENSIERRA

I ended up pulling the motor and got it torn down, everything still looked brand new but my new cam didn't have PTV clearance so I ended up building a 408 with all new bearings.
oil pump o ring still looked good but my engine guy tore the oil pump apart and cleaned everything so I really hope all is well when it goes back together.
sorry I couldn't help

phnxfrhwk

No problem. Guess I'll just run it until it breaks. Then convince the wife I need high speed, go fast parts. Lol.