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Oil pressure sending unit?

88K5Jimmy

88K5Jimmy

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Tulsa OK
88K5
stock TBI 350

What is the thing located above the oil filter that has a wire going from the top of it? Is this the oil pressure sending unit? I seem to be loosing oil pressure at idle. I have normal pressure while driving but at idle, the gauge pegs to 0 and there is also oil leaking from the thing in question. Any ideas and part numbers by chance?
 
I think it's the bell shaped piece..I think it's leaking from where it connects to the block but I have no idea. I did read on a thread that the sending unit threads into a 90 degree elbow fitting and then that fitting threads into the block.

Local part store has a cylindrical looking thing that the wire connects to on one end and a threaded end on the other...

I'm kinda stumped...maybe a pic would help.
 
I probably should have worded it differently, I just wanted to make sure there was only one wire, not two. Since you have both a pressure switch and a sending unit, parts stores often sell people the wrong one.

Since you have oil pressure oddities, the sender may be faulty, but you might also want to put a known good gauge to the engine, just to make sure you don't have a gauge or wiring issue. Mechanical would make it quick and easy for test purposes, if you have access to one. Plus, mechanical isn't going to read incorrectly if there is a wiring issue.

I've never cut one of those senders open, I assume they have a rubber diaphram that may rupture and allow oil contamination, which could lead to some leaking and bad pressure readings. I'd verify both that the leak is not a fitting issue, and actual engine oil pressure, before replacing parts.

It's always good to know that the stock oil pressure gauge works...not worth replacing if it does, but you need to know that it is reporting oil pressure as it should.
 
Yeah..the main reason I was going to replace the sender or fitting or all the above was because I have a visible oil leak coming from that area. I get about a 3" puddle after its driven from that spot. But it does have the one wire, which i went through with the parts store. So I guess we'll see what the part looks like when I get it in.
 
Well it appears that its leaking from where the oil pressure sending unit thread onto the fitting in the block, or where the fitting threads into the block, or a combination of both. It is a bell shaped thing with one wire coming from it. Anybody replaced the fitting that screws into the block as well? Dealer only...part store...?
 
Probably need a good hardware store, it's probably a brass tube, maybe with a 45 or 90* angle on it.

As much as it's said not to use it, teflon tape. It's pipe thread, so almost certainly you'd get good contact with the block even with tape on it.
 
I was kinda thinking the same thing about a hardware store for replacement fittings. I guess that will be the fun part after I get it our of the block....hopefully
 
dyeager535 said:
Probably need a good hardware store, it's probably a brass tube, maybe with a 45 or 90* angle on it.

As much as it's said not to use it, teflon tape. It's pipe thread, so almost certainly you'd get good contact with the block even with tape on it.
Click to expand...

Believe it or not, the tape didnt allow mine to ground, used two wraps. Had to pull it and put it back in, didnt try one wrap works perfect now, no leaky.
 
So it worked ok with Teflon but you had to pull the sender and put it back in so the tape got a bit more shredded?

I'm very surprised that it wouldn't allow contact with the block! Maybe it IS more effective than I thought. Every time I've pulled something wrapped in Teflon there are thread cuts, so I assumed it would always make contact.

Can you simply test for continuity to ground on the senders to the block, or do you have to check resistance?
 
dyeager535 said:
So it worked ok with Teflon but you had to pull the sender and put it back in so the tape got a bit more shredded?

I'm very surprised that it wouldn't allow contact with the block! Maybe it IS more effective than I thought. Every time I've pulled something wrapped in Teflon there are thread cuts, so I assumed it would always make contact.

Can you simply test for continuity to ground on the senders to the block, or do you have to check resistance?
Click to expand...

After an engine swap and some tape on the sender the gauge wasnt reading. I was beat and simply grounded it to the block... gauge read correctly so I pulled the tape, good to go.
I was also very surprised there wasnt contact for the ground. Shoot, the tape was from HF:dunno::haha:.
 
lemme know if this works for your oil pressure problem. I sold a k-5 to my brother with the exact same problem. It was an 88 as well
 
muddermilitia said:
lemme know if this works for your oil pressure problem. I sold a k-5 to my brother with the exact same problem. It was an 88 as well
Click to expand...

I changed the oil pressure sending unit, upper engine oil cooler line (it had been leaking prior to the sending unit issue) and changed the oil. Pressure at normal drving is around 40-45 and at idle 30. So it looks like the oil pressure sending unit was bad afterall. It was actaully really easy to change. Heck, the oil took longer to change because the threads were messed up in the filter. I'll get part numbers for the cooler line and sending unit when I get home.
 
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