Oil leak behind distributor? -- 92 Sierra

[stella92350]

Hey everybody, first time poster here. I'd appreciate any help I could get with this oil leak. Here's my vehicle info:

 

1992 GMC Sierra SLE

350; 5 speed transmission (5LM60) 

 

I've never had any oil leaks till now, when I'd notice after a drive I'd park it and there'd be a little puddle after a few minutes. It smells like engine oil, and it looks like it's coming from the distributor or behind it, and running down the bell housing and eventually dripping down around the slave cylinder. 

One pic is attached and I'll post a couple more in separate posts due to the size limit. 

 

Thank you in advance for any help and I'll be standing by to answer any questions. 

[stella92350]

[stella92350]

This is just behind the distributor. 

[riverbanks]

Oil pressure sending unit

[stella92350]

Thank you! This, right? 

[riverbanks]

Yep

[stella92350]

Appreciate it. Looks like I'll have "fun" changing that out. 

[m&jtrans]

Intake manifold gasket or more likely it's the distributor gasket the most people forget about. They're a paper/cork style until later models they became an O ring seal.

Blue Mule

[m&jtrans]

If its the oil pressure sending unit (OPSU) wouldn't it register on the dash a low oil pressure on the gage or light??

 

Blue Mule

 

 

 

 

[stella92350]

Thanks, yeah it did actually start registering max oil pressure the past few days even with good oil level and all. So I was starting to wonder if the OPSU was faulty. Didn't realize till now it could leak like that, though.

[stella92350]

Okay, so I got the actual tool that was supposed to be for it, the Lisle 13250 socket that's 1 1/16" but it was too small. So I got the 1 3/16" version (Performance Tool W80591) and it's not long enough?? It's getting pretty obvious that this isn't the original engine, but is there anything else I could be missing here? The socket looks long and deep enough when I put it up next to the sensor, but it just doesn't reach. How many different varieties of oil pressure senders did GM put on their 80's-90's 350's?

 

Anyone else gone through this? The replacement sender I got definitely fits the 1 1/16 tool perfectly, so I'm assuming once I get the old one off I'll be alright installing the new one. And yes I'm trying to avoid removing the distributor if at all possible, but if I have to remove it then I will. 

 

The old one looks like the one in this pic: