Where is the leak? Oil Pressure Sending Unit Replacement

treehan77 · Oct 5, 2015

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 · Oct 5, 2015

treehan77 said:
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 · Oct 5, 2015

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 · Oct 5, 2015

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 · Oct 5, 2015

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 · Oct 5, 2015

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 · Oct 6, 2015

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 · Oct 6, 2015

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 · Oct 6, 2015

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 · Oct 14, 2015

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.

SLCHOE · Oct 15, 2015

Drop some kitty litter on the oil spot and let it sit for 15 minutes. Then come back and really grind it into the spots with your shoe. Sweep it up and if necessary, repeat. It will come out.

Pachanga02 · Oct 15, 2015

@SLCHOE will that work on old stains?

SLCHOE · Oct 17, 2015

Pachanga02 said:
@SLCHOE will that work on old stains?

For old stains the best stuff is actual kleen-sweep or similar products. Kitty litter may work but probably not as quick/well.

I have pulled old stains out of concrete before and the real stuff worked the best by letting it sit over top of the stain for 20 minutes and then moving it around with a pushbroom as to get fresh stuff back on top of the stain. Working it in with your foot also helps pull it out.

about20ninj45 · Oct 19, 2015

SLCHOE said:
For old stains the best stuff is actual kleen-sweep or similar products. Kitty litter may work but probably not as quick/well.

I have pulled old stains out of concrete before and the real stuff worked the best by letting it sit over top of the stain for 20 minutes and then moving it around with a pushbroom as to get fresh stuff back on top of the stain. Working it in with your foot also helps pull it out.

Does anyone a have a link to that part (oil sending unit) ? Mine is leaking as well and i want to tackle this asap. I want to get rid of the oil burning smells while im driving..ughhh

treehan77 · Oct 20, 2015

i got mine from amazon, i'm banking on delco since i really don't want to do this more than once.
Part
Also got this thread compound instead of the expensive GM stuff it says to use: Thread sealant (they have it at auto stores too for the same price basically)

SLCHOE · Oct 21, 2015

about20ninj45 said:
Does anyone a have a link to that part (oil sending unit) ? Mine is leaking as well and i want to tackle this asap. I want to get rid of the oil burning smells while im driving..ughhh

treehan77 said:
i got mine from amazon, i'm banking on delco since i really don't want to do this more than once.
Part
Also got this thread compound instead of the expensive GM stuff it says to use: Thread sealant (they have it at auto stores too for the same price basically)

Yep that's the part. You really don't need any thread sealant as the sensor comes with some pre-applied and also has a crush washer.

treehan77 · Oct 21, 2015

SLCHOE said:
Yep that's the part. You really don't need any thread sealant as the sensor comes with some pre-applied and also has a crush washer.

Interesting, the thing I read said apply some gm sealant and didn't mention the part already had it. Guess I'll get a refund for that six bucks thanks

SLCHOE · Oct 21, 2015

treehan77 said:
Interesting, the thing I read said apply some gm sealant and didn't mention the part already had it. Guess I'll get a refund for that six bucks thanks

Yeah no problem. Iif you look at the picture of the sensor, you can see the white sealant on the threads. I have installed many of these and never had any issues by not adding more GMS (GM Sealant).

treehan77 · Oct 23, 2015

Finally got some time to put the new part in. Gauge still works so....now just to see if my leak is gone. Does this old one "look" like it was leaking? It's fairly clean...

Pachanga02 · Oct 23, 2015

What part did you guys get I got mine yesterday from Autozone and the sensor they gave me has one pin and mine has 3 and although plug is the same it doesn't go in the new sensor. I went back and checked with the old part number that's on the original sensor and it brings up the same sensor they gave me. Could it be delco only?

Where is the leak? Oil Pressure Sending Unit Replacement

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