Low oil pressure caused by sludge in oil?

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CODE5

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Is there a possibility the amount of coolant that was in my engine previously did a number on the oil sending unit eventually making it malfunction? Wondering if I should drain the engine and add a new filter when I change the unit, I'd hate to short out another sending unit becuase of gunk in my engine...
 

g.hayduke

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Contents inside the valve cover… head clearly had a crack between cylinders 3/4. Will be unbolting the exhaust so I can drop the pan to see what is inside when I drain the oil here soon.

View attachment 391206

That looks more like contaminated oil than what I would label "sludge". Seems unlikely to clog anything. I would just change the oil again using the correct 10w30 and expect no more issues - before pulling the pan.
 

Squatch

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I have an honest question, here: Is there a reason why more of us aren't running a mechanical oil pressure gauge? My wife's XJ has had a malfunctioning sending unit for a while, now, and as this is the second one to go bad, I'm about ready to make the switch to a mechanical unit. Just seems like it would be a better way to get an accurate reading. Any reason to not do so? If I were the OP, I'd be considering the same, just for the peace of mind.
 
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I have an honest question, here: Is there a reason why more of us aren't running a mechanical oil pressure gauge? My wife's XJ has had a malfunctioning sending unit for a while, now, and as this is the second one to go bad, I'm about ready to make the switch to a mechanical unit. Just seems like it would be a better way to get an accurate reading. Any reason to not do so? If I were the OP, I'd be considering the same, just for the peace of mind.

I'm considering it - I'm going to have to order one with a hose so that I can see it in the cab... My other question, IF i install a mechanical one, how do I get the one on the dash to quit beeping at me and flashing "Check Gauges"?
 

BlueC

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I'm about ready to make the switch to a mechanical unit. Just seems like it would be a better way to get an accurate reading. Any reason to not do so?

My issue with mechanical is that little plastic line of pressurized oil, and where it runs to/by. They are fine until they're not, at which point you have pressurized oil dripping and/or spraying, most likely into the cabin, usually behind the dash onto electrical components which tend to get hot. I think it would be wise to hard-mount a mechanical gauge directly to the engine, and use electrical gauges for going into the cabin. Kind of a best of both situation. Use the in-cabin electrical as a heads-up, and under hood mechanical for verification. I'll likely take this route.
1673633060505.png


When my dads Corvette was taken apart, we figured out that the mechanical oil gauge had been leaking onto the radio, for who knows how long, which explained why the radio was getting worse with time. Had that car not been taken apart, it would have likely only been a matter of time and heat before a fire. C3 gauges are directly above the radio.
1673632927213.png
 
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Squatch

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My issue with mechanical is that little plastic line of pressurized oil

I have used copper tubing for mine. I don't care for the plastic lines, either. The only one I have ever had fail was a plastic line. Fortunately, I had it set-up with a T-fitting where I was able to simultaneously utilize the idiot light. The idiot light immediately caught my attention, and I was able to shut it down quickly, thereby minimizing the mess (though it was definitely still a mess), but more importantly, saving the engine.
 
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Squatch

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My issue with mechanical is that little plastic line of pressurized oil, and where it runs to/by. They are fine until they're not, at which point you have pressurized oil dripping and/or spraying, most likely into the cabin, usually behind the dash onto electrical components which tend to get hot. I think it would be wise to hard-mount a mechanical gauge directly to the engine, and use electrical gauges for going into the cabin. Kind of a best of both situation. Use the in-cabin electrical as a heads-up, and under hood mechanical for verification. I'll likely take this route.
View attachment 391526

When my dads Corvette was taken apart, we figured out that the mechanical oil gauge had been leaking onto the radio, for who knows how long, which explained why the radio was getting worse with time. Had that car not been taken apart, it would have likely only been a matter of time and heat before a fire. C3 gauges are directly above the radio.
View attachment 391525

Could always do it old-school...;)

car-show-42-gauges-on-car-hood-exterior.jpg
 

Gollywomper

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I'm considering it - I'm going to have to order one with a hose so that I can see it in the cab... My other question, IF i install a mechanical one, how do I get the one on the dash to quit beeping at me and flashing "Check Gauges"?

Maybe a diode between wires to make it read somewhere in the middle
 
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Rickyd

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As others have said- mechanical gauge to test pressure first. A new mopar oil sender(the only one to get) won't necessarily solve the gauge drop and beeping,the rest of the circuit and electrical connections need to be taken into account. It didn't on my 97. Freaked me out after a new stroker install. I verified great warm idle oil pressure with 2 different mechanical oil gauges.

Seafoam or other flush.then Put the correct 10w-30 and new filter in it.


I'd probably wait on dropping the pan until trying the above things.then install a high volume oil pump while I'm in there.A good flush or two with seafoam would be mandatory to me after having that crap in your oil. Your lifters and everything else will thank you
 
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hear

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As others have said- mechanical gauge to test pressure first. A new mopar oil sender(the only one to get) won't necessarily solve the gauge drop and beeping,the rest of the circuit and electrical connections need to be taken into account. It didn't on my 97. Freaked me out after a new stroker install. I verified great warm idle oil pressure with 2 different mechanical oil gauges.
my 97 had the all too familiar oil pressure to 0 + check gauges problem. I replaced the sender (did not use Mopar) but still had the problem. I was doing the RMS anyway, so I decided to replace my oil pump with a Melling. Never had the oil pressure gauge fall to 0 again. Alls well that ends well, but I should have tested the pressure with a mechanical gauge before I did all that.
 
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As others have said- mechanical gauge to test pressure first. A new mopar oil sender(the only one to get) won't necessarily solve the gauge drop and beeping,the rest of the circuit and electrical connections need to be taken into account. It didn't on my 97. Freaked me out after a new stroker install. I verified great warm idle oil pressure with 2 different mechanical oil gauges.

Seafoam or other flush.then Put the correct 10w-30 and new filter in it.


I'd probably wait on dropping the pan until trying the above things.then install a high volume oil pump while I'm in there.A good flush or two with seafoam would be mandatory to me after having that crap in your oil. Your lifters and everything else will thank you

That is the plan. I'm searching the various local stores to find a mechanical gauge since we're hours away from the weekend - the only time I really have to tinker on the ol Jeep. I've also got to solve this awful noise that started after I installed the new head gasket... 98% sure I have an exhaust leak since that manifold gave me fits to get back on... The ticking along with this oil pressure has me concerned.

 

macleanflood

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If you do install a mechanical gauge install a 1/8" street T so you can connect both the original Mopar sender and your aftermarket gauge.

I prefer an electronic gauge...comes with it's own sensor and wires.

I've been meaning to hook up a meter to my Mopar sensor and read the voltage or resistance. You'd think we could add a circuit that would be adjustable with some rheostats to bring it within range of what the computer wants to see.

-Mac
 
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24B7CD89-6A9D-45A2-A4AA-BF97F177371D.jpeg


We’re back! Installed the new oil pressure sensor and took a ride to warm up the engine. 40 psi cold — once warm goes to about 20 psi at idle. Goes up when I’m driving. Not bad right?

BF1A9325-6E50-40E5-812B-743ACBB460AA.jpeg
 
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Still got this noise I’m chasing down but glad my oil pressure is good. Next up, changing the engine cleaner oil to fresh 10w-30 and replacing the filter.


 

Squatch

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Don't confuse oil pressure with oil flow...

I had a '71 Grand Prix that had over 80 psi when running at full temperature. Turns out the 400 had spun the cam bearing that had the oil port hole in it. Nothing was getting up to the rockers, but damn, it had great oil pressure! ;)
 

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I had a '71 Grand Prix that had over 80 psi when running at full temperature. Turns out the 400 had spun the cam bearing that had the oil port hole in it. Nothing was getting up to the rockers, but damn, it had great oil pressure! ;)

That’s exactly my point.
Over in the Harley world, first-time owners always flip their wig when they come to a stop sign and see the oil pressure hovering around zero on their brand new, warmed-up V-Twin…
 
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