loss of oil pressure and low end knock

Joined
Feb 21, 2021
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Panama city , FL
As i was headed to my in laws on Christmas day when all of a sudden I start hearing a loud knock like I had no oil . I pulled over and checked my dipstick and had oil on the stick .I got back in cranked it up and the knock was gone and oil pressure showed a little below half . I got about a mile from them and the knock started again and the oil pressure dropped. got to their house and the knock was gone again if i revved it up it would knock but then stop like it was being starved for oil . I am assuming that my oil pump is gone . I have recently done an oil change with a toyota oil filter and also put seafoam in with it not a week before ... what are the chanced something has clogged my pickup? i drained the oil back out and found no metal so i am hoping maybe an oil change will fix it but i know better ... has anyone else had this kind of issue and do i have to remove the steering bar to get my pan off?
 
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Feb 21, 2021
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Panama city , FL
it has 289k on it. and i put it in before i did the oil change to hopefully clean up some stuff inside the engine ... ran it for a week did the oil change .. then about a week later this happened
 
Joined
Nov 9, 2012
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Olathe, KS, USA
i always run 10w40 mobil 1
It's probably good your were running even that heavy to begin with.

Try a heavier oil to see if it eliminates the problem.

It is rarely the oil pump on these. Bad oil pressure typically kills the big end main bearings first.

How many miles on the truck?

Any maintenance history?
 
Joined
Feb 1, 2016
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Fort Mill, SC
I presume the idea to put in Sea Foam was to 'clean' the engine out. The problem, as I see it, if your engine actually needs this cleaning out because it has deposits from oil that has been run for so long it's essentially turned into black lacquer in the engine, then the last thing you would want to do is to have all of that stuff break free in the engine at the same time. It can clog oil passages, oil pick-up screens, etc. So the only time I've ever seen the rationale to do this 'cleaning' is just before you are going to tear an engine down for rebuild.

So, was this the first time you added Sea Foam or is this something you do before each oil change?
 
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Oregon
I have recently done an oil change with a toyota oil filter and also put seafoam in with it not a week before
Just to be clear, are you saying that you ran Seafoam in the old oil for one week before changing the oil and filter?

I've personally run Seafoam in the crankcase on a few vehicles, including my 80. Usually just for a period of idling, but a week of driving with it seemed to help a persistent stuck lifter on a Jeep 4.0. Never had a problem with it, which is not to say that it's impossible.
 
Joined
Dec 10, 2007
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What oil filter had you been running when this happened and how old was that filter? Has the coolant level in your overflow tank or radiator been dropping recently? Any overheating or clouds of sweet smelling vapor out the tailpipe?

Have you already tossed out the old oil?

If you still have the used oil you can send a sample to Blackstone labs for an Engine Oil Analysis (EOA). That will show if you have high wear metals ie: to help determine if damage was done. It will also show you the lowered viscosity due to using the Seafoam and if there was any coolant in the oil ie: from a leaking head gasket.

If you call Blackstone they will send you free oil collection bottles, if you prepay for six tests they will include free return shipping.

 
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Joined
Feb 21, 2021
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Panama city , FL
there is 289872 miles on the engine . i have only done 2 oil changes since i got the truck this was my third. and yes i ran seafoam for a week in the old oil .. then did the oil change and then this happened a week later. i usually use wix oil filters but this last time i used a toyota d3. i checked for metal in the oil and found none also didnt look to be any coolant in the oil. as far as loosing coolant it had been loosing some recently but i also had a leaking water pump which i changed when i changed the oil so i wouldnt have noticed .... but yes there has been smoke coming out the tail pipe but its been doing that since i got it and it burns and looses oil fast about a quart a month which is why i am always topping it off between the changes . i assume its worn rings. also i noticed a leak on the side plate of the engine. how hard is it to reseal that or is my best bet at this point to just pull the engine and rebuild it on a stand
 
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Feb 1, 2016
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Fort Mill, SC
You said you are loosing oil from the side plate, so I'm guessing this is an early 80 series with the 3fe that has the cover for the pushrods. That's an easy gasket to change and will help you determine how much is being burned and how much is leaking out. After you change it confirm no other leaks, like the oil pan gasket or valve cover gasket. With regards to the oil burning issue, when does it smoke? Continuously, just at startup, when you let off the gas and then give it gas again? There are many reasons why an engine would smoke and determining when it smokes will help diagnose the cause. And engine tear down should be your last resort, it's no small feat, as you must already know.
 
Joined
Feb 21, 2021
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Panama city , FL
it smokes only at startup once it warms up its fine . and yes its a 11/91 3fe . and speaking of pushrods i had one about a month ago that i had to go in and adjust them because the screw had backed itself out and with the valve cover off and engine running the pushrod was never touching the valve rocker. it started as a slight tick then got to a loud tick. dont know if that will help anything with my current problem but figured i would add that in there. so its a new valve cover gasket . i am also about to go ahead and drop the oil pan and replace that gasket and inspect the oil pump, any tips?
 
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Dec 10, 2007
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Not saying this is the cause of your problem, but Wix oil filters have a very bad reputation on this forum; a couple of people have had their engines fried due to a failed Wix filter.
 
Joined
Feb 21, 2021
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Panama city , FL
well i pulled my pan this weekend ...... found the rod bearing on cyl 5 has spun into itself and overlapped in 4 places basically interconnecting ... cyl 6 is also loose but not as bad I have not pulled the cap on it yet. I pulled the oil pump it looks good except for some scoring at the bottom plate . My plan is to order 1 std bearing set and plastigauge all 6 to see what sizes i will need. The end cap and the journal on the shaft looks good still
 

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