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I installed a new oil pump last night and this morning and can't pressure. Need help. Also I tried searching on here and it kept saying no results... So I'm sorry if I'm being that guy. I just need help priming the pump. If you want to read more for the details, by all means. 


The details... Have a 2013 5.3 and bought the melling 365 pump. I did the larger washer on the passenger side of the pick up tube instead of using the original place to bolt in... That's the only place I deviated from Chilton's. I'm worried the o ring isn't seated but I want that to be my last resort obviously because this job sucks. I'm honestly about 95% sure it's seated tightly. 


When I installed the pump, I poured oil into the pump and filled the filter. Put 6qts of oil in and now I pulled the fuse for the injectors and coils (I think fuse 13 and 24) and trying to starter prime it with the starter. Just go to start the truck for a few seconds then turn it off. I've done that about 5 times now and tried plugging in the fuses and starting it. It ran for about 3-5 secs before I turned it off because I didn't see pressure. 


When starter priming, it looks like it builds maybe 2psi of pressure. I'll attach a video

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  • 5 years later...

Hi: I just finished installing a reman 5.3L, installed the pickup tube as instructed, primed the pump and used the air pressure method while turning the engine slowly until i could see oil coming out of each lifter, put everything together, pulled the fuel pump and injector fuse, gave the engine exactly seven turns holding each time for 7 seconds, plugged the fuel pump and injector fuse back in, started the engine and immediately got a tapping noise, shut the engine off and repeated the priming cycle several more times without success, I'm considering pulling the engine and sending it back for a new one, it seems a reman can sometimes not be all that good, praying the next one will work better, sure hate to do all that work again.



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Lifters take a while to fully pump up in some cases. If it's not a lower end knock like a rod bearing the engine is likely just fine. If you have good oil pressure, the engine should be good to go.

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