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I have a 5.3 in my 04 silverado. Has a 148k miles on it, just switched to synthetic oil 5k miles ago and yesterday when I started it to let it run for a while since it's been on jack stands for a month.... I heard a real bad ticking from it. And my knock sensor(s) have been out for ~50k miles.... if I swap them is there a chance it will correct the ticking? Or is it too late at this point and am I looking at an engine rebuild???
 

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well switching to synthetic oil at 148k miles was a bad move in my opinion... syntheic has more cleaning agents in it. so all them miles of running conventional oil it builds up gunk or sludge in the engine. how much depends on your oil change schedule. not when you switched to synthetic it turned all that sludge a loose and more than likely there was still a little bit of conventional left in there and when mixed with synthetic it will also sludge up.. so if you take all that sludge and it starts going to the lifter ports it usually stops them up. and they done pressure up like they are supposed to and thats what you are hearing. lifters ticking more than likely. i would have recommended when you drained your old oil out that you run a engine flush with the same synthetic oil you intended using and let that run for 15 mins. drain and then fill with new oil. that way you get most of that sludge and conventional oil out of your truck before running synthetic all.. also any vehicle over 100k miles thats been running conventional oil in it. i never recommend switching anyway simply because your engine could star burning oil due to oil film being removed by the synthetic oil and your engine seals and valve cover gaskets could start leaking. but those things are hit and miss.
 

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Wow...so much misinformation!

Josh...ur lifters might have bled out and u got a tick from them. Did the ticking go away after a few mins of driving?

At 148k, I wouldn't be surprised if a lifter or two are weak.

Synthetic wil not sludge if mixed with conventional, by the way. Any sludge or big chunks woukd be caught by ur filter unless its sludge right by the heads. Easy way to check for sludge is removing a valve cover.
 

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I'm sorry I guess ASE mechanic that's seen a diesel engine lose oil pressure and burn up an engine. Due to the fact that he switched to royal purple last oil change. And when tore down found in the filter gel and sludge. You know you can read all over Google and talk to the oil manufacturers and they all say that synthetics and conventionals mix doesn't hurt. I've heard it time and time again. But I've seen gas and diesel engines start giving oil pressure problems after switching. So Josh believe whoever you want to believe. Doesn't matter to me.
 

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Well I had a shop do the oil change for me and he highly recommended it since I was having the rest of the driveline changed.
 

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And before the change I hadn't had any burning oil. I changed conventional oil ever 3k miles and I'll be changing synethic every 5k
 

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good! diesel oil doesnt have detergents like gas engine oil does, so comparing those two is not a good example. Who knows what the maintenance was on that engine he says he saw...and being ASE certified means nothing, I know guys who are and I wouldnt trust them with my vehicle. That driver mustve pushed his rig hard if he had lost oil psi and burned the motor...trucks have warning lights for everything, wouldnt put it past an idiot driver to have ignored the alarm :shrug:

Keep an eye on your oil pressure once you start pushing past 8k miles, if u intend on leaving it in there for that long. Some oil filters will not like the extra time in service and you can drop a few psi (5-10psi is what Ive seen)...happened to me when i left my wix filter in there for 10k miles...swapped it out and was fine.
 

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I'm sorry I guess ASE mechanic that's seen a diesel engine lose oil pressure and burn up an engine. Due to the fact that he switched to royal purple last oil change. And when tore down found in the filter gel and sludge. You know you can read all over Google and talk to the oil manufacturers and they all say that synthetics and conventionals mix doesn't hurt. I've heard it time and time again. But I've seen gas and diesel engines start giving oil pressure problems after switching. So Josh believe whoever you want to believe. Doesn't matter to me.
If synthetic oil and conventional oil aren't supposed to mix, then why do they offer Syn-Blend on semi synthetic?:snoopfacepalm:
 

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Everything Ed says is true.

Everything Tommy said is false.
 

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If synthetic oil and conventional oil aren't supposed to mix, then why do they offer Syn-Blend on semi synthetic?:snoopfacepalm:
Synthetic blends dont exist!

Don't the 5.3s have oil pump o ring problems?
 

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Mine ticks during cold startup.

If OP is in cold climate, could be piston slappage.
 

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Synthetic blends dont exist!



Don't the 5.3s have oil pump o ring problems?

Synthetic blends do actually exist, fyi.

Piston slap is very common with the 5.3 and as far as I know it's harmless. I usually let mine run until it goes away then drive it.
 

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Allow me to correct this post.

Synthetic blends dont exist! :troll3:

Don't the 5.3s have oil pump o ring problems?
Better??

Synthetic blends do actually exist, fyi.

Piston slap is very common with the 5.3 and as far as I know it's harmless. I usually let mine run until it goes away then drive it.
Idk about harmless, but it is common.

I ain't no expert but just going by what I've seen on the store shelves
http://www.havoline.com/docs/Havoline_Synthetic_Dep_Shield_PDS.pdf
See above correction
 

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Allow me to correct this post.







Better??







Idk about harmless, but it is common.







See above correction

Sorry, not harmless I guess, definitely wears shit out faster but there's not much we can do, as far as I know there's no permanent fix for the cold engine knock. Mine has definitely gotten a lot better since I got the truck a year ago, I can't hear it unless I drive while it's still knocking. it was really bad when I got it. Running a good regular oil helps a lot. Too late for me to go synthetic, maybe a blend but not full synthetic. I use Quaker state high mileage
 

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:facepalm: u can go to syn any time
 

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Wow you people are not very forgiving, what I meant is I don't want to switch to synthetic at 160k miles, I've had bad experience with that in the past. Sorry for posting my opinion.
 
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