Where is the leak? Oil Pressure Sending Unit Replacement

[treehan77]

Noticed a drip in the driveway last week, not much but enough to notice. Changed the oil 4000 miles ago, wasn't super low or anything, but i got up under there and its all wet now, it was dry 4000 mi ago, or I didn't notice somehow. Hopefully some of you smarter guys can tell me where the leak likely is coming from. It looks wet above the filter and oil pan, but hard to tell. I took a few shots to see if anybody could tell me whats most likely. It is a 2005 Yukon 4.8L. Also, what are the round caps things in the second to last pic, the larger one rattles when i touch it.

 

[SLCHOE]

Noticed a drip in the driveway last week, not much but enough to notice. Changed the oil 4000 miles ago, wasn't super low or anything, but i got up under there and its all wet now, it was dry 4000 mi ago, or I didn't notice somehow. Hopefully some of you smarter guys can tell me where the leak likely is coming from. It looks wet above the filter and oil pan, but hard to tell. I took a few shots to see if anybody could tell me whats most likely. It is a 2005 Yukon 4.8L. Also, what are the round caps things in the second to last pic, the larger one rattles when i touch it. View attachment 56546 View attachment 56547 View attachment 56548

1) Oil pressure sending unit leaking on top of the rear intake manifold and seeping down onto the bell-housing of the trans, etc. Pretty common issue. I bet your oil pressure gauge is acting funny too. And if it's not yet, it will be soon. Pretty easy/cheap fix. Could also be a valve cover gasket leaking in the rear area but my $$$ is on the oil pressure sending unit. Only way to know for sure is with a flashlight and a mirror at the rear of the intake (up against the firewall) and visually determine the source.

2) it's in inspection cover on the trans. It will rattle as it's just a piece of thin aluminum. Not a concern.

 

[treehan77]

Forgot to mention the oil pan gasket was replaced last July and here been about 7000 miles put on since then.

Schloe, what all is involved? Is there a DIY for this? If its easy, i might do it. How much would a dealer charge? Thanks! My oil pressure gauge seems to working fine ( i got the stepper motors done a few months ago and its worked fine since). Is this something some Lucas Stop Leak could tackle?

 

[SLCHOE]

Depends on which issue it is. The oil pressure sending unit or the valve cover gaskets. Either way, I'd say with a simple toolset on a saturday, about $100 or less and an hour for the oil pressure sending unit or 2-3 hours for the valve cover gaskets. Most shops charge $90-$100 per hour. If they let you supply your own parts, Amazon is a great place for that otherwise there will be significant markup on parts.

 

[treehan77]

thanks, i finally found a link that looks like what i need to do. has anyone else got the sending unit out with just removing the shroud like this guy, it looks like its not hard but hard to see.

http://www.tahoeyukonforum.com/threads/engine-oil-pressure-sensor.11041/

 

[SLCHOE]

Looks like this:

Gasket is part of it (the "washer"). Just need to make it snug, not too tight. Once the washer gives, it will feel like it stops turning. That is where you stop.

 

[treehan77]

sweet thanks! so basically i just remove the VORTEC cover and i wriggle in there and can get it i guess. i will report back after this is done, probably two weekends before i can get to it...

 

[SLCHOE]

Yep. You will want an oil pressure sender socket to do it easily.

http://www.amazon.com/Lisle-13250-Pressure-Switch-Socket/product-reviews/B0002SR2RY

Prepare for a few scrathes and light cuts on your hands/arms if you've never done it before. You can't really see it so you have to do it by touch more than anything.

A tip for reinstallation is to use just enough electrical tape to keep the new sender in the socket to install it (so it doesn't fall out back there) but not too much that when you try to pull off of the sender your socket stays stuck to it.

It's a lesson you have to learn really. You'll be fine. LOL

Oh and get a can of brake cleaner too. When you are done, clean all of that residual oil off from the top down. That way you know if/when you have another leak in that area.

Good luck.

 

[SLCHOE]

Honestly, that hardest part is getting the connector off as it is just a tab-lift mechanism but the way it usually sits is to where it's against the intake and you cant get a finger in there to release the tab so I personally end up using a pocket screwdriver to release the tab and the other hand to pull it free. I'd say 80% of the time the tab is facing that way.

 

[Pachanga02]

Looks like we have the same leak. Changed out the valve cover gaskets and it was good for a few days. I may have to try and get this done soon I ruined my driveway with these little spots. Hopefully this is the answer to my problem and I'll be able to get my driveway sealed afterwards.