Uh oh...oil leak - photos included

[azgolfrat]

About 2 days ago I noticed a small amount of oil under the car, front/center location. I put the car up, took off the back cover, and had a look...


I think this location is where the tranny and block meet. the pictures are taken from underneath, on my back, camera angled up from the passenger side.

Anyone dealt with this before? 2015 V8 w/126K miles. Been a good car.

 

[azgolfrat]

A little more info... the leak accelerates when the car is in park and running...5-10 drops per minute. The location is just beyond the flexplate towards the front of the car. There is a plastic door that can be removed for loosening the flexplate bolts. With the door removed, I put my fingers in there while the engine IS NOT running, and there is oil present and there should not be. My best guess at this point is pretty bad failure of the rear main seal. I was able to collect the fluid and look at it very closely. Pretty sure it is motor oil and not t-fluid.
Has anyone fixed there own rear main seal? Other thoughts?
Thanks

 

[azgolfrat]

A little more info... the leak accelerates when the car is in park and running...5-10 drops per minute. The location is just beyond the flexplate towards the front of the car. There is a plastic door that can be removed for loosening the flexplate bolts. With the door removed, I put my fingers in there while the engine IS NOT running, and there is oil present and there should not be. My best guess at this point is pretty bad failure of the rear main seal. I was able to collect the fluid and look at it very closely. Pretty sure it is motor oil and not t-fluid.
Has anyone fixed there own rear main seal? Other thoughts?
Thanks

More info
So its possible the problem is a leaking oil pressure sensor. Other Hyundai / Kia models have the oil pressure sensor located in the valley between cylinder heads, underneath the intake manifold(s). I've downloaded a manual for the 2015 5.0 , but its not the best - probably translated. I read there is a "oil temperature" sensor in the valley, but I am pretty sure it is meant to read "oil Pressure sensor", but I don't know for sure.
Do any of you have insight here?
BTW - when this oil pressure sensor leaks, it creates exactly the symptoms I have seen, per a youtube video on the topic

https://i.ytimg.com/vi/GhTEaYIGC1M/maxresdefault.jpg

 

[carguy75]

I used to own a 2015 5.0 model and the oil pressure sensor is in the front of the engine next to the crank pulley. It seems that you may have an rear main leak based on the pics. However, it may be from another source like the cam cradle, upper oil pan or valve cover. Oil leaks can start from the upper part of the engine and trickle down.

 

[azgolfrat]

I used to own a 2015 5.0 model and the oil pressure sensor is in the front of the engine next to the crank pulley. It seems that you may have an rear main leak based on the pics. However, it may be from another source like the cam cradle, upper oil pan or valve cover. Oil leaks can start from the upper part of the engine and trickle down.

Thanks, especially for the information on the oil pressure sensor location.
I've seen rear main seal leaks before...in my experience they have been very slow. This one came on pretty quickly and is leaking like a sieve! However, my 1st thought was the rear main seal. Thanks again.

 

[carguy75]

Thanks, especially for the information on the oil pressure sensor location.
I've seen rear main seal leaks before...in my experience they have been very slow. This one came on pretty quickly and is leaking like a sieve! However, my 1st thought was the rear main seal. Thanks again.

No problem.

I hope that your leak is not the rear main, but if it is then the transmission do not seem that hard to unbolt and move out of the way if you have experience repairing rear main leaks.

Here the oil pressure sensor on the 5.0 engine.

 

[azgolfrat]

Thanks. Digging through the repair manual , I see there is an oil temperature sensor in the valley. It provides some type of feedback used in the variable valve timing. I can get a look at it by taking off the intake manifolds I think. Just not sure if it could cause this large of a leak.
I've done a front seal before on my Mercury Marauder, and I pulled the transmission and engine from that car, but never changed a rear seal. I saw in the 5.0 manual...it does look like getting to the rear seal can be done once the transmission is out of the way. ooof.

 

[carguy75]

Thanks. Digging through the repair manual , I see there is an oil temperature sensor in the valley. It provides some type of feedback used in the variable valve timing. I can get a look at it by taking off the intake manifolds I think. Just not sure if it could cause this large of a leak.
I've done a front seal before on my Mercury Marauder, and I pulled the transmission and engine from that car, but never changed a rear seal. I saw in the 5.0 manual...it does look like getting to the rear seal can be done once the transmission is out of the way. ooof.

I did not notice an oil temp sensor on the valley cover, but I could have over looked it. It also possible to have a valley cover oil leak as well that could run down the back of the engine. The problem with modern engines is that there are many places for leaks to happen that requires major disassembly to even inspect the engine properly.

My old 2015 5.0 valley area.

 

[azgolfrat]

Thanks! Agreed on the potential for leaks. If I get this resolved I will let you know what the leak source was.

 

[azgolfrat]

I started to take the car apart to get a look at the valley, and it seemed to me it was going to be very tough without at least having the transmission removed, if not the engine. The high fuel pressure line and a mounting nut are both in a location that really isn't accessible otherwise.
I gave up. Last night I traded the car in against a 2023 Lincoln Aviator. I will miss the Genny. It was a good car.

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