Oil pressure dropping off

[Itsme7]

Hi everyone. I have a 2005 Silverado 1500 5.3 engine code B. Currently sitting at 96.5K miles. So for the past 3-4 months, ive been noticing my oil pressure dropping off. It would start of, i'd be fine the entire time until i got close to the end of a oil change, and it would go down slightly. With fresh oil and hot in park, it would idle at 35 or so PSI (40+ cruising) The last oil change, it dropped off to around 25 psi right before i did a oil change. Now im sitting at 2400 after a oil change, and PSI is sitting between the 20-25psi mark on the gauge. This drop really has me worried. Looking at the oil level, its fine and in the hash mark, no problems. The coolant level is within where it should be on the overflow bottle. Im at a loss and dont know what to do. At this point im almost contemplating just getting rid of my truck. Anyone know what could possibly be the problem? I did notice oil residue by the bell housing and oil pan area, but low oil isnt the issue since its showing up on the dipstick as within range. Can anyone help?

 

Thanks very much, any suggestions are appreciated.

[gmtech4]

i cant copy and paste this

 

engine oil pressure hot minimum

 

6 psi @ 1000 rpm

 

18 psi @ 2k

 

24 psi @ 4k

[Itsme7]

So the 20-25PSI is acceptable? Im just worried of the sudden drop. Do you think running 5w30 full synthetic castrol edge could be the issue and thinning out?

[gmtech4]

i wont answer that as i am a wrench not an oil composition expert

 

nothing wrong with dino oil,

 

again the aftermarket loves you guys,, $$$$$ in their jeans

[txab]

Why not have your pressure double checked by a mechanical gauge.

[Itsme7]

Im thinking about it. Ive read of the digital gages dieing and not being reliable.

[txab]

Sending units can act up

[Itsme7]

Thanks for some reassurance. I'll check that out ASAP, probably install a mechanical gauge

[Itsme7]

After reading up, im not sure if i should be worried about castech head issues or not? From what i can tell im not using coolant, is there any way to tell if this would be the issue? Would coolant contamination of the oil cause the pressure drop im seeing?

[txab]

http://www.agcoauto.com/content/plugins/p2_news/printarticle.php?p2_articleid=148

[Itsme7]

Keeping an eye on my oil pressure and coolant level. If either drop much more, im going to further investigate. Worst comes to worst, time for some remanufactured heads, arp head bolts, and gaskets.

[markw8]

I think your worrying too much about oil pressure. Why are you know worried about your heads? Is it loosing coolant, or too much forum reading?

 

Mark

[gmtech4]

I think your worrying too much about oil pressure. Why are you know worried about your heads? Is it loosing coolant, or too much forum reading?

 

Mark

 

 

he said the coolant level is fine

[markw8]

I think your worrying too much about oil pressure. Why are you know worried about your heads? Is it loosing coolant, or too much forum reading?

 

Mark

 

 

he said the coolant level is fine

 

 

I know that, but then he says he's keeping an eye on it after reading about problems with castech heads.

 

Mark

[txab]

You're getting a little ahead of yourself. Get the pressure checked with a reliable mechanical gauge, then go from there. Quit worrying about your heads. If you are concerned take a sample of oil and have it analyzed for traces of coolant.