I recently did a 5.3 swap in my 98 blazer and am having a strange issue come up. The motor sat in the weather before i got it and has a bunch of miles on it and was cruddy inside the valve covers. So i put fresh oil in it when i got it in and added some sea foam to clean up the build up. well the oil pressure was normal for a while then i noticed rocker arm tapping sound and noticed there was no oil pressure. I shut it off .. checked oil level and it looked good. cranked it back up and was fine again.
I figured the sea foam was doing its job and maybe the filter was getting clogged so i changed it out and didnt have a problem again till yesterday..a week later. yesterday i noticed the oil pressure guage was way pegged out. I thought it was a glitch with my wiring or maybe a bad sensor until i noticed it only does it when i start it up..like it is actually reading right. so now im worried ..then i ran into it losing all oil pressure again on a drive around the block ..rockers tapping and all..shut it off check oil again..looks good..and start it back up and is pegged again but the rockers arent tapping..

What could cause these two issues? Im having a random almost like a clogging and seems like a stuck pressure regulator?

 

depening on the year of the motor, not to sure on the 5.3's but the LS1 had a oil pressure relief valve problem where the valve can get caught in the sharp castings that were not debured by gm. in 2001 they started using the same LS6 pump in the LS1. i had the problem on mine recently at 92k miles.

 

ouch...im thinking im screwed on this one then..guess im just going to have to drop the pan and change the pump out..ugg..this is turning out to be the absolute worst swap ever!

 

To change the pump you will need to remove the crank pulley and timing cover, and drop the pan just a little. The pump is on the front of the crank.

 

oh wow just did a search on pics and should be alot easier than i had thought..this is my first lsx motor so most of the orientation of things is a lil new to me lol..guess im going to price a pump

 

It's easy to get to but the pulley is a pain to get on and off. You will need a way to lock the crank (I used a tool from summit), a puller, and it's best to use a tool to re-install it rather than just a longer bolt.

 

ok thanks...and the balancer cant be no worse than my lt1 balancer removal and install lol.
I am just going to pull the pump out deburr and port it in the appropriate areas..clean and possibly deburr the press. regulator and shim it for a lil extra pressure.. then clean the heck out of the clogged pick up tube...considering how expensive these pieces are for my budget i dont see no reason for a replacement part.

 

http://www.ls1howto.com/index.php?article=23

follow this guide man it will help you out. its pretty much the same for the 5.3

 

thanks man.. i actually ran across that article right before i went to drop the pan..So far so good on the oil pressure. I dont know how much crud and buildup i cleaned out of the bottom of the pan and windage tray not to mention the very clogged up pickup tube. So i will have to say that seafoam is definitely not good to run in a high mileage motor that apparently has missed a few oil changes lol