Pesky oil leak on this 1998 2.4L

Hey everyone

have this oil leak on my 98, having a hard time locating.

Valve cover is intact and sealing properly, pcv valve and grommet okay, oil pan is good, drain plug good, where do I go from here?

I posted some pics, and the final resting place of the oil. Anything helps! Thanks

 

Image 1- mounting bolt (?) where exhaust manifold meets engine. Dirtiest part and looks suspicious, could oil seep from this?

image 2- oil filter mount, pretty wet and oily, could be from above?

image 3- oil pressure switch, seems relatively dry compared to the rest

image 4- zoomed out image 1

image 5- final resting place on bottom of rms

 

Engine degreaser and oil dye.
That’s about the best way to locate it.

 

10-4 thank you mane

 

When you get the valve cover off next time find a flat surface like a piece of glass and see if you see a gap or slide a feeler gauge under it.

 

Bc no pix of front of engine

Guessing rear main seal

Like TN states
Buy shit ton of degreaser/brake cleaner
Coin Op car wash
Roll up on car ramps
Get dirty/wet while pwr washing laying on ground

Then monitor

I used that oil dye b4……works
But I had to do 3 oil changes to get all that die out….IMO was not worth it

 

I think I found it with the help of the dye. Seems to be seeping from in between the oil filter mount and the block. Thank you guys

 

@spinrod97 I am currently working in the same area on my 2000, and am trying to orient myself with your first image, the oily bolt that holds the exhaust manifold to the cylinder head. Am I correct in saying that photo is taken looking up from underneath? I have a similar oily bolt at the exhaust manifold, looking up, although your bolt is a little more oily than mine.

And you used dye to learn that the "leak" was coming from the large sealing gasket (O-ring) that fits between the oil filter bracket and the block, right, and that point is below the oily bolt at the exhaust manifold, so the leak you discovered did not put the oil on the exhaust manifold bolt, that must have occurred in the past, maybe when the valve cover gasket last failed?

My current project came about when my valve cover gasket broke in several places from age, but a worse problem was an extreme oil sludging event that I only saw when I removed the valve cover. I am now guessing for myself (now that I have it all put back together) that the oil on the bolt in the exhaust manifold in my 2000 got there when the gasket gave way, and what I see now is a residual effect, and not a primary leak, which would match your observations. So, if I could do a better degreasing, I might do away with that oily look, to some extent.

Does what I said above all sound correct to you?

Finally, that oil on your transmission case, did your newly discovered leak travel all the way to that same place? If not, you may have a rear main seal leak on top of the oil filter bracket seal leak, but if it is still active, you should be able to see the dye there as well, but unless you dribbled oil from your observed leak and watched it travel down to that spot, you would not know for sure from where the dye actually came.

 

Spot on with pretty much everything you said, pretty sure that exhaust bolt was just a build up from valve cover before repair. After oil filter bracket, valve cover gasket, oil pressure switch, the leak slowed down to the point where it hasn’t dripped once off the bottom transmission in about 2 weeks. But it is still leaking, as the buildup is coming in the same place, just very slow now. I think it’s the RMS. Gonna wait another week or two and foolishly cross my fingers that whatever is dripping down now is from the spills during the previous projects, although that probably would’ve burned off by now. Time will tell, good luck with yours!

 

@spinrod97 When I first thought of the potential for oil leaks from doing the job I did (desludging the engine without removing it) and considering all the linear feat of "seal" surfaces that had to go just right during that job (valve cover, oil pan, timing cover, front crank oil seal, rear main seal, along with the seals in the transmission, I gave myself a ZERO % chance of getting all of that done without any leaking.

So, when I had put it all back together and it started, I was not at all surprised to see that there were leaks. The first oil leak was dripping oil at about a drip per second. It came from the connection of the oil pressure gauge to the adapter needed to go from NPT to BSPT so I could get the gauge screwed into the threaded hole where the oil pressure switch originally went, so wasn't one of the seals I had to get right in the project.

There was still another major leak, but this time it was coolant leaking from around where the heater hoses go through the firewall. Both heater core nipples (or tubes) coming through the firewall were bent when someone took the original hoses off, and one person who did that was myself. I am still dealing with that leak, and will continue until it is fixed, but obtaining the parts has been a hassle.

Finally, there is a single oil leak, that drips about once every time I have the truck out, and that has only been a couple of times already. I am thinking it is the O-ring between the oil filter bracket and the block, so have ordered that gasket to see if that fixes that last leak.

Bottom line: and here I am patting myself on the shoulder ahead of facts that still might come out, but having the truck back together from all that work, it is possible that all of the sealing jobs I did in this major project might have been a success. I will let you know if I have to eat these words.

But, chasing oil leaks isn't a job I enjoy. That's for sure. And, my wife's Infiniti just started leaking. . . never ends!!