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Discussion Starter #1
Have a 6bt in my 74 f250

Started noticing a decent amount of oil dripping from the drivers side. It appears it is possibly coming from the pressure sending unit.

I did a search and saw a few people mention that some sending units cant handle the pressure (gas engine style units) . Not sure if this is what is happening or if I need to remove and use some sealant on the threads and reinstall? any thoughts?

My oil pressure pegs my gauge 100PSI gauge on start up and while accelerating and bounces between 50-75 psi at stops or at cruise. not sure how accurate this is and if I need to look at a different setup.
 

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Three quick thoughts:

1. Wrap a strip of paper towel around the base (threaded part) of the oil pressure sending unit. Secure it with a twist-tie or zip-tie. It the leak is at the threaded connection or base of the sender, the paper towel will oil soak.

2. Electric oil pressure senders are known to go bad. Temporarily install a 0 -100 PSI mechanical gauge to see if the oil pressure readings are the same.

3. If you verify oil pressures of over 100 PSI, I suspect a faulty pressure relief valve somewhere inside your 6bt. That is "above my pay grade".
 

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I had an factory electric oil pressure guage leak when going downhill, had a hard time figuring it out when in the mountains.

Ed in CO.
 

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I'd agree with Russ that if your true oil pressure is running 100 PSI you have a problem with the relief valve. Those are factory set at 65 PSI. There might be a spike on cold start up but you shouldn't have any continuous reading that high. There are 2 control valves on the oil filter plate. One is the oil pressure regulator which is located behind a 22mm hex plug on the front side of the filter plate. Those do get sticky sometimes. Might unscrew that plug and check to be sure that unit is moving freely. The oil pressure relief valve is located on the back side of the filter plate and can only be accessed by removing the plate. That one carries Cummins part 3936365. If you replace that you'd also need the correct filter plate gasket as well.
 

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Discussion Starter #6 (Edited)
Thanks for the reply’s! Appreciate the input. Oil is leak has increased over the past few times driving it.

I am not sure what is original in regards to the filter setup and what was changed during the swap. Here is a picture of my filter setup. Is this a stock setup?


128601
2ED5869D-56D5-4516-ACEE-E752F8106025.jpeg
76C43F8D-0A26-4F81-A07A-EF67F3739900.jpeg
 

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Appears to be the standard vertical oil filter plate normally found on 6bts. If you look to the front of that plate up top you'll see that hex plug I mentioned. Below is a diagram that shows all the parts. Wouldn't be hard to check the oil pressure regulator to be sure it isn't stuck. Just unscrew the cap, and fish out the spring and plunger. If they come out easily that probably isn't an issue. The relief valve which is part #2 would require removing the plate to get at it. That part costs around $20 give or take a little. The gasket which is part #8 is typical of the 12 valve engines unless you happen to have a STORM block. Then it would look like #13 in the second diagram.
 

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Discussion Starter #8 (Edited)
Thanks for the pics

I Pulled the hex plug and the plunger and spring came out easily and looked to be in good shape and clean, so I reinstalled.

Wondering if I should order a new pressure valve and gasket and pull the plate off? Or should I verify the oil pressure with a different gauge/sender first.
Is this correct part? 3936365
128626
 

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I believe I'd check to be sure the gauge is reading correctly. Some factory gauges and sending units aren't all that true. There is a second port on that oil filter plate where you could attach a separate gauge to get a comparative reading. That is plug #4 in the first diagram. I believe that port is threaded 1/8" NPT.
 

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Discussion Starter #10 (Edited)
I installed a pressure gauge directly to the filter plate. Its a 0-160PSI liquid filled gauge so hoping its accurate enough, but when I first start truck up my autometer gauge is reading 100PSI and my new gauge at the filter is reading 65psi. Will try to get some reading later after driving around a little bit, but initially it appears my gauge/sending unit is definitely off.

Autometer said to double check the ground wire from the gauge and to also check sending unit fitting where it attaches to block. Probably going to pull unit and use some teflon tape on threads and reinstall. He said it is very rare for the sending unit to leak/fail

this new gauge just screws in at the filter so I cant really monitor while driving but figure i can compare some hot and cold readings at idle or while someone revs motor in neutral to get a better idea what's going on

What PSI should I be seeing with this motor? Looks like maybe 65-75 cold start up is normal and should drop down to 30-50 while running warm?
 

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Your pressure readings sound perfectly normal. The new gauge is giving readings we'd normally expect. The pressure relief valve is set at 65 PSI and your cold readings aren't wondering much above that. Once warmed up you readings are also normal. Sounds like the issue is in the Autometer gauge. Although few do it, a pure mechanical gauge gives very accurate readings. Guys just don't like having an oil line inside the cab.
 
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