I know the classic chain slap is out there but i've been messing around and studying my truck. I posted a pic bellow of an oil pressure guage its just about the same as mine. Between the 2 middle marks is ideal oil pressure. I've been watching mine go quite low toward the very bottom line sometimes but then other times its in the middle perfect. But the thing of it is i've noticed since my chain slap is intermident and happens here and there, that when my chain is slapping the oil pressure is way lower than it should be. Now being the chain tensioner oil pressure controlled does it seem like something is wrong? Oil pump issue? Wrong Oil? I keep her exactly full of oil all the time. Most of the time When shes dead cool there is no noise until it heats up then the slap and oil pressure low.... any ideas? Cause i'm thinking about changing the pump.

 

How long since last oil change? "Used" oil can run lower than fresh.

 

have you checked your guides? if they arent broken yet ide look at an oil pump, and possibly an aftermarket guage setup, at idle its suppose to have 4.3 psi MINIMUM and at 3000 36-71..now mine on the other hand when cold and idle its at 50-55and when warm rolls around 45, and tops out at 70 ish when revving n such, might be cuz its newer? or cuz i have stuff in my pickup tube, lmao

 

when do you hear the chain slap?

I think I can hear mine occasionally on a start up for like a second or two.
It sounds as if it makes noise till oil gets to it.

It never makes noise while driving or revving it though

 

When in doubt always use a mechanical gauge to check the pressure. I tend to be skeptical of tired old sending units that feed information to tired old wires.

Your chain slap is more likely related to low oil pressure than vice versa.

 

Well if its on first start up in the mornings there is not chain slap for about 20mins. After she warms up, sometimes it slaps randomly for a period of time and usually the oil pressure is low when it does this. If the chain is not slapping all the time it would lead me to believe that its not guides. At first i thought it was the tensioner but maybe a combination of both. Oil has been changed reg after 3k miles all the time and the chain noise is there no matter what. After its been warmed up and i turn it off, then back on i will here slapping then it will stop. Its funny cause i only here the noise at idle toabout 1500 rpms then it kinda goes.... but thats only if its doing it. It does it about 60% of the time the trucks on. Usually when hot and oil pessures low....

 

You could try installing shims under the pressure relief valve spring in your oil pump to see if you can raise your oil pressure to where it needs to be.

The reason you aren't hearing chain noise when you first start the truck is because your oil is nice and thick which causes higher pressures. What weight oil are you running?

 

Yea i knew that about morning starts but would that not def rule out defective chain and guides 100%? I'm running 10w30 at the moment. And its been running that about most its life. I thought about going thicker. I've put 10W40 in it with the same result. I'd rather not tamper with the pump if i don't have to but maybe so....

 

Also seems like the truck runs better under higher oil pressure which is understandable i guess due to proper lubrication and cooling but eh wooppiieee.

 

Intermittently low oil pressure makes me think something (probably busted chain guide parts) works around at times to partially block your oil intake. Could be chunks from the existing timing guides or even prior ones if someone didn't clean out the pan.

 

mmhmm interesting when me and my stepdad replaced the chain and guides we didn't remove the pan just the head due the fact it needed a headgasket too. But the slapping seems to happen at set times. Usually always at idle(when warmed up). When cold theres is no noise at all..... not so much after noise 1500rpms. hmmm interesting but i'm not looking forward to messing with the pan especially since it does not leak a drop right now.

 

Were your old guides broken?

I'm only speculating, but maybe sitting overnight allows the plastic chunks to settle to the bottom of the pan, where they stay until the oil thins out enough after warming up the next day.

Maybe at 1500+ RPM, even with a partially blocked oil intake, you have enough pressure for the chain tensioner to eliminate the obvious rattle, but that doesn't mean your oil pressure is where it should be.

 

Keep in mind that I don't have much experience with this and am just throwing out a possibility. Your problem may lie elsewhere. Can a screwed oil pump pressure relief valve work ok when cold, but at times release way too early when warm? I don't know how they tend to fail.

 

Yea its a good thought you put in there for me, i'll def keep it in mind. Yea one of the old gudies was broke clean off and slapping the cover and rubbed a hole in that as well. Course that was once upon a time and is now fixed... but yea. Dropping the pan and cleaning it and changing the oil would eliminate this but thats not a fun job.....lol I was thinking of getting a new pump but damn they are like 90-150$....