Engine Won't Stop Leaking Oil...

[pbdm4k]

About a week after I picked up the Pathfinder, I decided to give it an oil change.

 

So i drained out all the gunky stuff that just looked downright horrendous and in went a few bottles of Castrol Syntec (I know, its probably too expensive to be using on a pathfinder this old, but its the only oil I had sitting in the garage for my other cars.)

 

Unluckily for me, I couldn't fit the new filter in (clearance issues). I tried stealing the filters from my brother's 240sx, but I couldn't make it fit. So I stuck the old one back in as a for the meantime kinda deal.

 

A day later, I verified with Nissan that the 240sx filter was the same, so I drained the oil, and forced the 240 filter into the crevice and managed to screw it on. (Yes I oiled the seal first!).

 

Anyways, I poured the "old" oil back in (I used a clean bucket), and the engine still seems to be leaking engine oil. The drain plug is secured on and just last night I tightened up the filter with an oil filter wrench. This morning low and behold I still have an oil leak!

 

Any ideas where this is coming from?? Could the seal around the oil filter be damaged?

[Simon]

Could be the oil pan gasket, or the rear main seal. Those suggestions are both assuming you're seeing the oil on the oil pan. Also, it could simply be run off from taking the filter off. I know my truck "seems" to leak for a couple days after a change, but it's just the old oil running down the block, to the oil pan from the filter location.

[88pathoffroad]

It;s leftovers from the filter removal. Rinse the area with a hose and degreaser and I bet it will stop within a few days.

[pbdm4k]

I performed the oil change last Sunday I believe so it's already been over a week.

It kept slowly leaking and I can see oil collecting on the bottom of the oil pan.

 

I retighened the oil filter last night, and this morning was a new puddle of oil.

 

Should I replace the oil pan gasket?

 

Where is the rear main seal located?

 

I'm not afraid of dropping the oil pan as I've done this before on my other cars, but I have no clue what or where the rear main seal is.

[DryBear]

Another thing to check is the oil pressure sensor - thats where mine was anyway.

[88pathoffroad]

Oilpan isn't a common leak, plus you'd have to drop the front diff to change it. Rear main is between the trans and engine, so you'd have to pull the trans/t-case to get to that.

 

Common leaks are: valve covers, oil pressure switch next to the oil filter, and sometimes the rear main.

[pbdm4k]

Oilpan isn't a common leak, plus you'd have to drop the front diff to change it. Rear main is between the trans and engine, so you'd have to pull the trans/t-case to get to that.

 

Common leaks are: valve covers, oil pressure switch next to the oil filter, and sometimes the rear main.

 

Is engine oil collecting on the oil pan a particular sign for any of these?

[k9sar]

the oil pan is at the bottom so anything leaking above it will run/drip down. best suggestion is to wipe everything clean (well... not everything. pan edge, filter, under sending unit, around valve covers, wherever you see oil/gunk) and then feel around after 10 min or so of running and see where there is oil. If it's running from somewhere, you should be able to locate it.

 

Rear main seal leaking usually shows at bottom of bell housing.

Sending unit leak is usually on the pan

Filter leak is usually on the pan

valve cover leak could go just about anywhere.

[k9sar]

craziest leak I ever tracked down was a pinhole leak on the top side of my oil filter. Would only leak when engine was running and drip would run down the seal for the filter. I could have sworn it was the seal on the filter but I was under it while it was running and I spotted the droplet.

[DryBear]

One thing that could help spot where the leak is coming from is that florescent oil dye that shows up with a black light. You add it to your oil, run the engine, and use the black light to spot where the leak is coming from. Usually works well.

[M in KC]

Maybe a dumb and too late of a comment but was the old oil filter's o-ring present on the old oil filter when you removed it? They can become adhered to the filter mount location. And in your first post you said the oil was horrendous which to me would indicate the oil and filter had been on that motor for some time. If that was the case the old filter's o-ring seal could still be on the filter mount and when the new filter was screwed on it leaks. Just a thought. Additionally I have heard of oil filter that have split, cracked or in k9sar's case pin holed and subsequently caused a leak.

[lunchindabox]

Maybe a dumb and too late of a comment but was the old oil filter's o-ring present on the old oil filter when you removed it? They can become adhered to the filter mount location. .......... If that was the case the old filter's o-ring seal could still be on the filter mount and when the new filter was screwed on it leaks. Just a thought.

 

I concur. I used to change oil at Firestone and have seen the old ring stay on the mount several times. Eeasiest way is to check your old filter and make sure it is there. If you don't have the old one anymore, remove the one you put on, clean the area and put on a new one. Worse case is it cost you 20 minutes and 4 bucks. I doubt anything else is wrong. It would have to be a big coincidence to have all of a sudden started after the oil change.

[94extreme]

it's leaking because of the synth oil cleaned everything up, including old plugged up holes in gaskets.. change it back to regular dyno.

[adamzan]

it's leaking because of the synth oil cleaned everything up, including old plugged up holes in gaskets.. change it back to regular dyno.

 

Yeah, same thing happend to me, now I run 20w50 in the summer 10w40 in the winter. But i now have a spot the size of a quarter after a while of running.

 

If you can't find any obviously leaks, change the oil to a thicker viscosity of regular oil. That helped me out.

[pbdm4k]

the oil pan is at the bottom so anything leaking above it will run/drip down. best suggestion is to wipe everything clean (well... not everything. pan edge, filter, under sending unit, around valve covers, wherever you see oil/gunk) and then feel around after 10 min or so of running and see where there is oil. If it's running from somewhere, you should be able to locate it.

 

Rear main seal leaking usually shows at bottom of bell housing.

Sending unit leak is usually on the pan

Filter leak is usually on the pan

valve cover leak could go just about anywhere.

 

Well, don't think I'll have time to really get under there and look until probably the weekend again.

I'll try to give the sending unit a whirl, and maybe a filter relocation kit will come in handy so i dont have oil dripping down all over the exhaust everytime i do an oil change.

 

*crosses fingers* I hope I can find that stupid leak...

[BLouisGod]

like red said, just use thicker oil. i went from 10w30 to 10w40 and bam, no more valve cover leaks.

[adamzan]

like red said, just use thicker oil. i went from 10w30 to 10w40 and bam, no more valve cover leaks.

 

Wow i usually never get any support on that comment, even though I know its true!

[pbdm4k]

like red said, just use thicker oil. i went from 10w30 to 10w40 and bam, no more valve cover leaks.

 

I'll give it another oil change this weekend. I was using 5w30 syntec, so I guess all the detergents knocked everything loose.

The oil actually drips out black so it was like the oil was never changed.

 

On my other cars, new oil drips transparent like its supposed to.

 

One day with a new oil change on the Pathfinder and it was dripping black.

 

I'll try using some 10w40.

 

Would that castrol high mileage oil make a difference?

 

I was told to throw in a treatment of bardhal or that engine treatment stuff for the next oil change too, let everything in the engine clean itself out.

[BLouisGod]

I think whats left there needs to stay there. If you had a new car and wanted to clean and condition seals, then yeah, but on high milege cars, things are they usually holding fluids back. The high milege stuff is up to you, my pathy at 150k prolly wont notice the difference. let us know what happens.

[unccpathfinder]

in my 87 i ran reg casterol all the time..then i got the bright idea to change to the high mileage and it started leaking like a sieve

[pbdm4k]

I put in 10w30 Castrol GTX. Still looks like its leaking. However the leak is a lot slower now.

 

Should I just throw in a bottle of Stop Leak on the next oil change?

 

Would I have to use that Stop Leak stuff everytime I change the oil?

[95shakinPF]

YOU DO NOT WANT TO DO THAT!!! Have you any idea what that s*%@#t will do to the oil passages throughout the block? Trust me,like some of the others said already. Just clean your engine real good(degreaser), run it a little bit and start looking for the leak. I betcha you will find its a valve cover or sending unit causing the problem. If u start adding a bunch of crap to your engine(additives,etc.) you will regret it later, I promise!

[pbdm4k]

YOU DO NOT WANT TO DO THAT!!! Have you any idea what that s*%@#t will do to the oil passages throughout the block? Trust me,like some of the others said already. Just clean your engine real good(degreaser), run it a little bit and start looking for the leak. I betcha you will find its a valve cover or sending unit causing the problem. If u start adding a bunch of crap to your engine(additives,etc.) you will regret it later, I promise!

 

Duely noted. I'll keep the stop leak crap out of the engine. I'll leave the 10w30 for now and let it drip.

[Xmas]

Here is mine.

 

 

This morning I took off the passenger side tire and looked at the oil pressure sending unit and oil filter. No leaks around it.

Also getting under the truck and looking up and on top/around the valve covers front and rear and there is no indication of oil leaks.

 

So where do you think mine is coming from??

[95shakinPF]

If you are absolutely sure that your oil sending unit and filter are not the problem. And your 100% sure the valve covers are not the source of the leak, bad news cuz!! You've got a rear main leaking!