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Oil Pressure Sending Unit


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Apr 14, 2002
Pacific Northwet
Has anyone out there had to change out their oil pressure sending unit on an 8.1L? If so, how hard was it to remove in that tight little spot? I work with a guy that just bought an '04  2500 and his gage just crapped out (he still has pressure though).

Well I never changed mine and I just read my manual then looked at engine. It is so far under the firewall I don't see how you can reach it without moving the engine forward 

Manual did mention a tool j41712 but don't see hows that's going to help


Thanks Steelhead Chaser for showing me the Avalanche!?

I just bought an '04 2500 Avalanche and the oil pressure gauge stopped working about 1 1/2 days after I bought it.? Went to Shucks got a new sending unit but could not find where it was located on the engine.? Steelhead Chaser and I were able to locate it yesterday at work.? Today I attempted to replace it.? You need a 1-1/16" deepwell socket I also used a 12" extension with a knuckle on it.? It took me about 5 minutes to get the old one out.?

Now comes the interesting part, I tried for over an hour to get the new one in.? Very limited space to work in.? Came up with a variety of techniques to try and get the new unit started but nothing seemed to work.? Finally after impressing my Neighbors with my command of the English language my wife came out and suggested that maybe it was the wrong size.? Sure enough it was about 1/32" bigger then the stock one :E:? ? It then took me 3 tries to get the old one back in.? ?Now back to shucks to get my money back and off to the local Chevy dealership for the OEM sender!

If you like getting your hands dirty not to difficult to do (Buy the OEM).? If you don't have allot of time or patience take it to the dealership.? ?

My pleasure, Shoe. Glad to hear you like your Avalanche.
Are we sure it is oil sending unit gone bad?

Some gages do not work for the fun of it....

bad stepper motor or bad ignition swithc...

somethink to think about
Right, I was thinking the same - might not be the sender.

The reason a special tool is mentioned is that it's a special socket to remove it and install it.  Most chain auto parts stores also sell the same socket, you do need it if you don't want to risk ruining the sender :)
I thought the same thing so I tested the gage with the new sending unit.? The electrical connection on the new sending unit is fine so I hooked it up and connected it to a pneumatic fitting I had and put 50psi of pressure to it.? I turned on my engine and the oil pressure gage read 60 psi? as I bled down the air line the gage on my dash followed, added pressure it went back up, it does nothing with the old sender.?

FYI, GM's test procedure..

(The links won't work because this is an image.)



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